Hyojung Yoon, Amanda Ringland, James J Anderson, Sahibjot Sran, Soad Elziny, Cindy Huynh, Noriyuki Shinagawa, Samantha Badertscher, Rachel R Corrigan, Lauren Mashburn-Warren, Foued Amari, Min Chen, Vincenzo Coppola, Peter B Crino, Tracy A Bedrosian
{"title":"Mouse models of Slc35a2 brain mosaicism reveal mechanisms of mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy.","authors":"Hyojung Yoon, Amanda Ringland, James J Anderson, Sahibjot Sran, Soad Elziny, Cindy Huynh, Noriyuki Shinagawa, Samantha Badertscher, Rachel R Corrigan, Lauren Mashburn-Warren, Foued Amari, Min Chen, Vincenzo Coppola, Peter B Crino, Tracy A Bedrosian","doi":"10.1111/epi.18166","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>Brain somatic variants in SLC35A2 were recently identified as a genetic marker for mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). The role of SLC35A2 in cortical development and the contributions of abnormal neurons and oligodendrocytes to seizure activity in MOGHE remain largely unexplored.</p><p><strong>Methods: </strong>Here, we generated a novel Slc35a2 floxed allele, which we used to develop two Slc35a2 conditional knockout mouse lines targeting (1) the Emx1 dorsal telencephalic lineage (excitatory neurons and glia) and (2) the Olig2 lineage (oligodendrocytes). We examined brain structure, behavior, and seizure activity.</p><p><strong>Results: </strong>Knockout of Slc35a2 from the Emx1 lineage, which targets both cortical neurons and oligodendrocytes, resulted in early lethality and caused abnormal cortical development, increased oligodendroglial cell density, early onset seizures, and developmental delays akin to what is observed in patients with MOGHE. By tracing neuronal development with 5-Ethynyl-2'-deoxyuridine (EdU) birthdating experiments, we found that Slc35a2 deficiency disrupts corticogenesis by delaying radial migration of neurons from the subventricular zone. To discern the contributions of oligodendrocytes to these phenotypes, we knocked out Slc35a2 from the Olig2 lineage. This recapitulated the increased oligodendroglial cell density and resulted in abnormal electroencephalographic activity, but without a clear seizure phenotype, suggesting Slc35a2 deficiency in neurons is required for epileptogenesis.</p><p><strong>Significance: </strong>This study presents two novel Slc35a2 conditional knockout mouse models and characterizes the effects on brain development, behavior, and epileptogenesis. Together, these results demonstrate a direct causal role for SLC35A2 in MOGHE-like phenotypes, including a critical role in neuronal migration during brain development, and identify neurons as key contributors to SLC35A2-related epileptogenesis.</p>","PeriodicalId":11768,"journal":{"name":"Epilepsia","volume":null,"pages":null},"PeriodicalIF":6.6000,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Epilepsia","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1111/epi.18166","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CLINICAL NEUROLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Objective: Brain somatic variants in SLC35A2 were recently identified as a genetic marker for mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). The role of SLC35A2 in cortical development and the contributions of abnormal neurons and oligodendrocytes to seizure activity in MOGHE remain largely unexplored.
Methods: Here, we generated a novel Slc35a2 floxed allele, which we used to develop two Slc35a2 conditional knockout mouse lines targeting (1) the Emx1 dorsal telencephalic lineage (excitatory neurons and glia) and (2) the Olig2 lineage (oligodendrocytes). We examined brain structure, behavior, and seizure activity.
Results: Knockout of Slc35a2 from the Emx1 lineage, which targets both cortical neurons and oligodendrocytes, resulted in early lethality and caused abnormal cortical development, increased oligodendroglial cell density, early onset seizures, and developmental delays akin to what is observed in patients with MOGHE. By tracing neuronal development with 5-Ethynyl-2'-deoxyuridine (EdU) birthdating experiments, we found that Slc35a2 deficiency disrupts corticogenesis by delaying radial migration of neurons from the subventricular zone. To discern the contributions of oligodendrocytes to these phenotypes, we knocked out Slc35a2 from the Olig2 lineage. This recapitulated the increased oligodendroglial cell density and resulted in abnormal electroencephalographic activity, but without a clear seizure phenotype, suggesting Slc35a2 deficiency in neurons is required for epileptogenesis.
Significance: This study presents two novel Slc35a2 conditional knockout mouse models and characterizes the effects on brain development, behavior, and epileptogenesis. Together, these results demonstrate a direct causal role for SLC35A2 in MOGHE-like phenotypes, including a critical role in neuronal migration during brain development, and identify neurons as key contributors to SLC35A2-related epileptogenesis.
期刊介绍:
Epilepsia is the leading, authoritative source for innovative clinical and basic science research for all aspects of epilepsy and seizures. In addition, Epilepsia publishes critical reviews, opinion pieces, and guidelines that foster understanding and aim to improve the diagnosis and treatment of people with seizures and epilepsy.