1
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Narvaiz DA, Blandin KJ, Sullens DG, Womble PD, Pilcher JB, O'Neill G, Wiley TA, Kwok EM, Chilukuri SV, Lugo JN. NS-Pten knockout mice exhibit sex and hippocampal subregion-specific increases in microglia/macrophage density. Epilepsy Res 2024; 206:107440. [PMID: 39213710 DOI: 10.1016/j.eplepsyres.2024.107440] [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: 05/22/2024] [Revised: 08/09/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024]
Abstract
Seizures induce hippocampal subregion dependent enhancements in microglia/macrophage phagocytosis and cytokine release that may contribute to the development of epilepsy. As a model of hyperactive mTOR induced epilepsy, neuronal subset specific phosphatase and tensin homolog (NS-Pten) knockout (KO) mice exhibit hyperactive mTOR signaling in the hippocampus, seizures that progress with age, and enhanced hippocampal microglia/macrophage activation. However, it is unknown where microglia/macrophages are most active within the hippocampus of NS-Pten KO mice. We quantified the density of IBA1 positive microglia/macrophages in the CA1, CA2/3, and dentate gyrus of NS-Pten KO and wildtype (WT) male and female mice at 4, 10, and 15 weeks of age. NS-Pten KO mice exhibited an overall increase in the number of IBA1 positive microglia/macrophages in each subregion and in the entire hippocampus. After accounting for differences in size, the whole hippocampus of NS-Pten KO mice still exhibited an increased density of IBA1 positive microglia/macrophages. Subregion analyses showed that this increase was restricted to the dentate gyrus of both male and female NS-Pten KO mice and to the CA1 of male NS-Pten KO mice. These data suggest enhanced microglia/macrophage activity may occur in the NS-Pten KO mice in a hippocampal subregion and sex-dependent manner. Future work should seek to determine whether these region-specific increases in microgliosis play a role in the progression of epilepsy in this model.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Joaquin N Lugo
- Department of Psychology and Neuroscience, USA; Department of Biology, USA; Institute of Biomedical Studies, USA; Baylor University, Baylor Center for Developmental Disabilities, Baylor University, Waco, TX 76798, USA.
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2
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Xu Y, Lu R, Li H, Feng W, Zhao R. A spectrum of AKT3 activating mutations cause focal malformations of cortical development (FMCDs) in cortical organoids. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167232. [PMID: 38759814 DOI: 10.1016/j.bbadis.2024.167232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/18/2024] [Accepted: 05/09/2024] [Indexed: 05/19/2024]
Abstract
Focal malformations of cortical development (FMCDs) are brain disorders mainly caused by hyperactive mTOR signaling due to both inactivating and activating mutations of genes in the PI3K-AKT-mTOR pathway. Among them, mosaic and somatic activating mutations of the mTOR pathway activators are more frequently linked to severe form of FMCDs. A human stem cell-based FMCDs model to study these activating mutations is still lacking. Herein, we genetically engineer human embryonic stem cell lines carrying these activating mutations to generate cortical organoids. Mosaic and somatic expression of AKT3 activating mutations in cortical organoids mimicking the disease presentation with overproliferation and the formation of dysmorphic neurons. In parallel comparison of various AKT3 activating mutations reveals that stronger mutation is associated with more severe neuronal migratory and overgrowth defects. Together, we have established a feasible human stem cell-based model for FMCDs that could help to better understand pathogenic mechanism and develop novel therapeutic strategy.
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Affiliation(s)
- Ying Xu
- Institute of Pediatrics, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Rongrong Lu
- Department of Neurosurgery, Children's Hospital of Fudan University, Fudan University, Shanghai 201102, China
| | - Hao Li
- Department of Neurosurgery, Children's Hospital of Fudan University, Fudan University, Shanghai 201102, China; Department of Neurosurgery, Xiamen Children's Hospital, Children's Hospital of Fudan University at Xiamen, Xiamen 361006, China
| | - Weijun Feng
- Institute of Pediatrics, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China; Fujian Key Laboratory of Neonatal Diseases, Xiamen Key Laboratory of Neonatal Diseases, Xiamen Children's Hospital, Children's Hospital of Fudan University at Xiamen, Xiamen 361006, China.
| | - Rui Zhao
- Department of Neurosurgery, Shanghai Children's Hospital, Shanghai 200333, China.
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3
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Yamada S, Mizukoshi T, Sato A, Sakakibara SI. Purinosomes and Purine Metabolism in Mammalian Neural Development: A Review. Acta Histochem Cytochem 2024; 57:89-100. [PMID: 38988694 PMCID: PMC11231565 DOI: 10.1267/ahc.24-00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Accepted: 05/19/2024] [Indexed: 07/12/2024] Open
Abstract
Neural stem/progenitor cells (NSPCs) in specific brain regions require precisely regulated metabolite production during critical development periods. Purines-vital components of DNA, RNA, and energy carriers like ATP and GTP-are crucial metabolites in brain development. Purine levels are tightly controlled through two pathways: de novo synthesis and salvage synthesis. Enzymes driving de novo pathway are assembled into a large multienzyme complex termed the "purinosome." Here, we review purine metabolism and purinosomes as spatiotemporal regulators of neural development. Notably, around postnatal day 0 (P0) during mouse cortical development, purine synthesis transitions from the de novo pathway to the salvage pathway. Inhibiting the de novo pathway affects mTORC1 pathway and leads to specific forebrain malformations. In this review, we also explore the importance of protein-protein interactions of a newly identified NSPC protein-NACHT and WD repeat domain-containing 1 (Nwd1)-in purinosome formation. Reduced Nwd1 expression disrupts purinosome formation, impacting NSPC proliferation and neuronal migration, resulting in periventricular heterotopia. Nwd1 interacts directly with phosphoribosylaminoimidazole-succinocarboxamide synthetase (PAICS), an enzyme involved in de novo purine synthesis. We anticipate this review will be valuable for researchers investigating neural development, purine metabolism, and protein-protein interactions.
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Affiliation(s)
- Seiya Yamada
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Saitama, Japan
- Neuroscience Center, HiLIFE-Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Tomoya Mizukoshi
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Saitama, Japan
| | - Ayaka Sato
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Saitama, Japan
| | - Shin-Ichi Sakakibara
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Saitama, Japan
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4
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Mizukoshi T, Yamada S, Sakakibara SI. Spatiotemporal Regulation of De Novo and Salvage Purine Synthesis during Brain Development. eNeuro 2023; 10:ENEURO.0159-23.2023. [PMID: 37770184 PMCID: PMC10566546 DOI: 10.1523/eneuro.0159-23.2023] [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: 05/15/2023] [Revised: 09/08/2023] [Accepted: 09/20/2023] [Indexed: 10/03/2023] Open
Abstract
The levels of purines, essential molecules to sustain eukaryotic cell homeostasis, are regulated by the coordination of the de novo and salvage synthesis pathways. In the embryonic central nervous system (CNS), the de novo pathway is considered crucial to meet the requirements for the active proliferation of neural stem/progenitor cells (NSPCs). However, how these two pathways are balanced or separately used during CNS development remains poorly understood. In this study, we showed a dynamic shift in pathway utilization, with greater reliance on the de novo pathway during embryonic stages and on the salvage pathway in postnatal-adult mouse brain. The pharmacological effects of various purine synthesis inhibitors in vitro and the expression profile of purine synthesis enzymes indicated that NSPCs in the embryonic cerebrum mainly use the de novo pathway. Simultaneously, NSPCs in the cerebellum require both the de novo and the salvage pathways. In vivo administration of de novo inhibitors resulted in severe hypoplasia of the forebrain cortical region, indicating a gradient of purine demand along the anteroposterior axis of the embryonic brain, with cortical areas of the dorsal forebrain having higher purine requirements than ventral or posterior areas such as the striatum and thalamus. This histologic defect of the neocortex was accompanied by strong downregulation of the mechanistic target of rapamycin complex 1 (mTORC1)/ribosomal protein S6 kinase (S6K)/S6 signaling cascade, a crucial pathway for cell metabolism, growth, and survival. These findings indicate the importance of the spatiotemporal regulation of both purine pathways for mTORC1 signaling and proper brain development.
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Affiliation(s)
- Tomoya Mizukoshi
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Seiya Yamada
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Shin-Ichi Sakakibara
- Laboratory for Molecular Neurobiology, Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
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5
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Shao Y, Ge Q, Yang J, Wang M, Zhou Y, Guo JX, Zhu M, Shi J, Hu Y, Shen L, Chen Z, Li XM, Zhu JM, Zhang J, Duan S, Chen J. Pathological Networks Involving Dysmorphic Neurons in Type II Focal Cortical Dysplasia. Neurosci Bull 2022; 38:1007-1024. [PMID: 35235180 PMCID: PMC9468210 DOI: 10.1007/s12264-022-00828-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/24/2021] [Indexed: 10/19/2022] Open
Abstract
Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy. Dysmorphic neurons are the major histopathological feature of type II FCD, but their role in seizure genesis in FCD is unclear. Here we performed whole-cell patch-clamp recording and morphological reconstruction of cortical principal neurons in postsurgical brain tissue from drug-resistant epilepsy patients. Quantitative analyses revealed distinct morphological and electrophysiological characteristics of the upper layer dysmorphic neurons in type II FCD, including an enlarged soma, aberrant dendritic arbors, increased current injection for rheobase action potential firing, and reduced action potential firing frequency. Intriguingly, the upper layer dysmorphic neurons received decreased glutamatergic and increased GABAergic synaptic inputs that were coupled with upregulation of the Na+-K+-Cl- cotransporter. In addition, we found a depolarizing shift of the GABA reversal potential in the CamKII-cre::PTENflox/flox mouse model of drug-resistant epilepsy, suggesting that enhanced GABAergic inputs might depolarize dysmorphic neurons. Thus, imbalance of synaptic excitation and inhibition of dysmorphic neurons may contribute to seizure genesis in type II FCD.
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Affiliation(s)
- Yijie Shao
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Qianqian Ge
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachao Yang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Mi Wang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yu Zhou
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jin-Xin Guo
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Mengyue Zhu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachen Shi
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yiqi Hu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Li Shen
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
- Department of Orthopedic Surgery, School of Medicine, the Second Affiliated Hospital, Zhejiang University, Hangzhou, 310009, China
- Hangzhou Innovation Center, Zhejiang University, Hangzhou, 310058, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, School of Basic Medical Sciences, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310058, China
| | - Xiao-Ming Li
- Center for Neuroscience and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Center for Brain Science and Brain-Inspired Intelligence, Joint Institute for Genetics and Genome Medicine between, Guangdong Hong Kong Macao Greater Bay Area, Zhejiang University and the University of Toronto, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jun-Ming Zhu
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jianmin Zhang
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
| | - Shumin Duan
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Jiadong Chen
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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6
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Schrötter S, Yuskaitis CJ, MacArthur MR, Mitchell SJ, Hosios AM, Osipovich M, Torrence ME, Mitchell JR, Hoxhaj G, Sahin M, Manning BD. The non-essential TSC complex component TBC1D7 restricts tissue mTORC1 signaling and brain and neuron growth. Cell Rep 2022; 39:110824. [PMID: 35584673 PMCID: PMC9175135 DOI: 10.1016/j.celrep.2022.110824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/21/2022] [Accepted: 04/23/2022] [Indexed: 11/16/2022] Open
Abstract
The tuberous sclerosis complex (TSC) 1 and 2 proteins associate with TBC1D7 to form the TSC complex, which is an essential suppressor of mTOR complex 1 (mTORC1), a ubiquitous driver of cell and tissue growth. Loss-of-function mutations in TSC1 or TSC2, but not TBC1D7, give rise to TSC, a pleiotropic disorder with aberrant activation of mTORC1 in various tissues. Here, we characterize mice with genetic deletion of Tbc1d7, which are viable with normal growth and development. Consistent with partial loss of function of the TSC complex, Tbc1d7 knockout (KO) mice display variable increases in tissue mTORC1 signaling with increased muscle fiber size but with strength and motor defects. Their most pronounced phenotype is brain overgrowth due to thickening of the cerebral cortex, with enhanced neuron-intrinsic mTORC1 signaling and growth. Thus, TBC1D7 is required for full TSC complex function in tissues, and the brain is particularly sensitive to its growth-suppressing activities.
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Affiliation(s)
- Sandra Schrötter
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Christopher J Yuskaitis
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael R MacArthur
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Sarah J Mitchell
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Aaron M Hosios
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Maria Osipovich
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Margaret E Torrence
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - James R Mitchell
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Gerta Hoxhaj
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Mustafa Sahin
- Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brendan D Manning
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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7
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Azoxystrobin Impairs Neuronal Migration and Induces ROS Dependent Apoptosis in Cortical Neurons. Int J Mol Sci 2021; 22:ijms222212495. [PMID: 34830376 PMCID: PMC8622671 DOI: 10.3390/ijms222212495] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/17/2022] Open
Abstract
Fungicides often cause genotoxic stress and neurodevelopmental disorders such as autism (ASD). Fungicide-azoxystrobin (AZOX) showed acute and chronic toxicity to various organisms, and remained a concern for ill effects in developing neurons. We evaluated the neurotoxicity of AZOX in developing mouse brains, and observed prenatal exposure to AZOX reduced neuronal viability, neurite outgrowth, and cortical migration process in developing brains. The 50% inhibitory concentration (IC50) of AZOX for acute (24 h) and chronic (7 days) exposures were 30 and 10 μM, respectively. Loss in viability was due to the accumulation of reactive oxygen species (ROS), and inhibited neurite outgrowth was due to the deactivation of mTORC1 kinase activity. Pretreatment with ROS scavenger- N-acetylcysteine (NAC) reserved the viability loss and forced activation of mTORC1 kinase revived the neurite outgrowth in AZOX treated neurons. Intra-amniotic injection of AZOX coupled with in utero electroporation of GFP-labelled plasmid in E15.5 mouse was performed and 20 mg/kg AZOX inhibited radial neuronal migration. Moreover, the accumulation of mitochondria was significantly reduced in AZOX treated primary neurons, indicative of mitochondrial deactivation and induction of apoptosis, which was quantified by Bcl2/Bax ratio and caspase 3 cleavage assay. This study elucidated the neurotoxicity of AZOX and explained the possible cure from it.
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8
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Reichard J, Zimmer-Bensch G. The Epigenome in Neurodevelopmental Disorders. Front Neurosci 2021; 15:776809. [PMID: 34803599 PMCID: PMC8595945 DOI: 10.3389/fnins.2021.776809] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/26/2022] Open
Abstract
Neurodevelopmental diseases (NDDs), such as autism spectrum disorders, epilepsy, and schizophrenia, are characterized by diverse facets of neurological and psychiatric symptoms, differing in etiology, onset and severity. Such symptoms include mental delay, cognitive and language impairments, or restrictions to adaptive and social behavior. Nevertheless, all have in common that critical milestones of brain development are disrupted, leading to functional deficits of the central nervous system and clinical manifestation in child- or adulthood. To approach how the different development-associated neuropathologies can occur and which risk factors or critical processes are involved in provoking higher susceptibility for such diseases, a detailed understanding of the mechanisms underlying proper brain formation is required. NDDs rely on deficits in neuronal identity, proportion or function, whereby a defective development of the cerebral cortex, the seat of higher cognitive functions, is implicated in numerous disorders. Such deficits can be provoked by genetic and environmental factors during corticogenesis. Thereby, epigenetic mechanisms can act as an interface between external stimuli and the genome, since they are known to be responsive to external stimuli also in cortical neurons. In line with that, DNA methylation, histone modifications/variants, ATP-dependent chromatin remodeling, as well as regulatory non-coding RNAs regulate diverse aspects of neuronal development, and alterations in epigenomic marks have been associated with NDDs of varying phenotypes. Here, we provide an overview of essential steps of mammalian corticogenesis, and discuss the role of epigenetic mechanisms assumed to contribute to pathophysiological aspects of NDDs, when being disrupted.
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Affiliation(s)
- Julia Reichard
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Geraldine Zimmer-Bensch
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
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9
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Szczałuba K, Rydzanicz M, Walczak A, Kosińska J, Koppolu A, Biernacka A, Iwanicka-Pronicka K, Grajkowska W, Jurkiewicz E, Kowalczyk P, Płoski R. Brain Tissue Low-Level Mosaicism for MTOR Mutation Causes Smith-Kingsmore Phenotype with Recurrent Hypoglycemia-A Novel Phenotype and a Further Proof for Testing of an Affected Tissue. Diagnostics (Basel) 2021; 11:diagnostics11071269. [PMID: 34359351 PMCID: PMC8303645 DOI: 10.3390/diagnostics11071269] [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: 06/06/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022] Open
Abstract
De novo somatic variants in genes encoding components of the PI3K-AKT3-mTOR pathway, including MTOR, have been linked to hemimegalencephaly or focal cortical dysplasia. Similarly to other malformations of cortical development, this condition presents with developmental delay and intractable epilepsy, often necessitating surgical treatment. We describe a first patient with the Smith-Kingsmore syndrome phenotype with recurrent hypoglycemia caused by low-level mosaic MTOR mutation restricted to the brain. We provide discussion on different aspects of somatic mosaicism. Deep exome sequencing combined with a variant search in multiple tissues and careful phenotyping may constitute a key to the diagnosis of the causes of rare brain anomalies.
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Affiliation(s)
- Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
- Correspondence: (K.S.); (R.P.); Tel.: +48-22-5720-695 (K.S. & R.P.); Fax: +48-22-5720-696 (K.S. & R.P.)
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
| | - Anna Walczak
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
| | - Joanna Kosińska
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
| | - Agnieszka Koppolu
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
| | - Anna Biernacka
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
| | | | - Wiesława Grajkowska
- Department of Pathology, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Elżbieta Jurkiewicz
- Department of Diagnostic Imaging, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Paweł Kowalczyk
- Department of Neurosurgery, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, Pawinskiego 3c Str., 02-106 Warsaw, Poland; (M.R.); (A.W.); (J.K.); (A.K.); (A.B.)
- Correspondence: (K.S.); (R.P.); Tel.: +48-22-5720-695 (K.S. & R.P.); Fax: +48-22-5720-696 (K.S. & R.P.)
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10
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Nguyen LH, Bordey A. Corrigendum: Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:715363. [PMID: 34295225 PMCID: PMC8290855 DOI: 10.3389/fnana.2021.715363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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11
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Nguyen LH, Bordey A. Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:664695. [PMID: 33897381 PMCID: PMC8064518 DOI: 10.3389/fnana.2021.664695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
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Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
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Specchio N, Pepi C, De Palma L, Trivisano M, Vigevano F, Curatolo P. Neuroimaging and genetic characteristics of malformation of cortical development due to mTOR pathway dysregulation: clues for the epileptogenic lesions and indications for epilepsy surgery. Expert Rev Neurother 2021; 21:1333-1345. [PMID: 33754929 DOI: 10.1080/14737175.2021.1906651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Malformation of cortical development (MCD) is strongly associated with drug-resistant epilepsies for which surgery to remove epileptogenic lesions is common. Two notable technological advances in this field are identification of the underlying genetic cause and techniques in neuroimaging. These now question how presurgical evaluation ought to be approached for 'mTORpathies.'Area covered: From review of published primary and secondary articles, the authors summarize evidence to consider focal cortical dysplasia (FCD), tuber sclerosis complex (TSC), and hemimegalencephaly (HME) collectively as MCD mTORpathies. The authors also consider the unique features of these related conditions with particular focus on the practicalities of using neuroimaging techniques currently available to define surgical targets and predict post-surgical outcome. Ultimately, the authors consider the surgical dilemmas faced for each condition.Expert opinion: Considering FCD, TSC, and HME collectively as mTORpathies has some merit; however, a unified approach to presurgical evaluation would seem unachievable. Nevertheless, the authors believe combining genetic-centered classification and morphologic findings using advanced imaging techniques will eventually form the basis of a paradigm when considering candidacy for early surgery.
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Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Chiara Pepi
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Luca De Palma
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Federico Vigevano
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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Pelorosso C, Watrin F, Conti V, Buhler E, Gelot A, Yang X, Mei D, McEvoy-Venneri J, Manent JB, Cetica V, Ball LL, Buccoliero AM, Vinck A, Barba C, Gleeson JG, Guerrini R, Represa A. Somatic double-hit in MTOR and RPS6 in hemimegalencephaly with intractable epilepsy. Hum Mol Genet 2019; 28:3755-3765. [PMID: 31411685 PMCID: PMC6935386 DOI: 10.1093/hmg/ddz194] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 01/19/2023] Open
Abstract
Single germline or somatic activating mutations of mammalian target of rapamycin (mTOR) pathway genes are emerging as a major cause of type II focal cortical dysplasia (FCD), hemimegalencephaly (HME) and tuberous sclerosis complex (TSC). A double-hit mechanism, based on a primary germline mutation in one allele and a secondary somatic hit affecting the other allele of the same gene in a small number of cells, has been documented in some patients with TSC or FCD. In a patient with HME, severe intellectual disability, intractable seizures and hypochromic skin patches, we identified the ribosomal protein S6 (RPS6) p.R232H variant, present as somatic mosaicism at ~15.1% in dysplastic brain tissue and ~11% in blood, and the MTOR p.S2215F variant, detected as ~8.8% mosaicism in brain tissue, but not in blood. Overexpressing the two variants independently in animal models, we demonstrated that MTOR p.S2215F caused neuronal migration delay and cytomegaly, while RPS6 p.R232H prompted increased cell proliferation. Double mutants exhibited a more severe phenotype, with increased proliferation and migration defects at embryonic stage and, at postnatal stage, cytomegalic cells exhibiting eccentric nuclei and binucleation, which are typical features of balloon cells. These findings suggest a synergistic effect of the two variants. This study indicates that, in addition to single activating mutations and double-hit inactivating mutations in mTOR pathway genes, severe forms of cortical dysplasia can also result from activating mutations affecting different genes in this pathway. RPS6 is a potential novel disease-related gene.
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Affiliation(s)
- Cristiana Pelorosso
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Françoise Watrin
- INMED, Aix-Marseille University, INSERM UMR1249, Marseille 13009, France
| | - Valerio Conti
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Emmanuelle Buhler
- INMED, Aix-Marseille University, INSERM UMR1249, Marseille 13009, France
| | - Antoinette Gelot
- Service d'Anatomie Pathologique, Hôpital Trousseau, Hôpitaux Universitaires de l'Est Parisien, Université Pierre et Marie Curie, Paris 75012, France
| | - Xiaoxu Yang
- Department of Neuroscience, Howard Hughes Medical Institute, Rady Children’s Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Davide Mei
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Jennifer McEvoy-Venneri
- Department of Neuroscience, Howard Hughes Medical Institute, Rady Children’s Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | | | - Valentina Cetica
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Laurel L Ball
- Department of Neuroscience, Howard Hughes Medical Institute, Rady Children’s Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Anna Maria Buccoliero
- Pathology Unit, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Antonin Vinck
- INMED, Aix-Marseille University, INSERM UMR1249, Marseille 13009, France
| | - Carmen Barba
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
| | - Joseph G Gleeson
- Department of Neuroscience, Howard Hughes Medical Institute, Rady Children’s Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Renzo Guerrini
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children’s Hospital A. Meyer, University of Florence, Florence 50139, Italy
- IRCCS Fondazione Stella Maris, Pisa 56126, Italy
| | - Alfonso Represa
- INMED, Aix-Marseille University, INSERM UMR1249, Marseille 13009, France
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