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Duan X, Peng X, Jia X, Tan S, Guo H, Tan J, Hu Z. CELF2 Deficiency Demonstrates Autism-Like Behaviors and Interferes with Late Development of Cortical Neurons in Mice. Mol Neurobiol 2024:10.1007/s12035-024-04250-0. [PMID: 38829512 DOI: 10.1007/s12035-024-04250-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 05/13/2024] [Indexed: 06/05/2024]
Abstract
CELF2 variants have been linked to neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD). However, the molecular mechanisms remain unclear. We generated Celf2 Nestin-Cre knockout mice.Our findings revealed that Celf2 Nestin-Cre heterozygous knockout mice exhibited social impairment and anxiety, an autism-like behavior, though no manifestations of repetitive stereotyped behavior, learning cognitive impairment, or depression were observed. Immunofluorescence assay showed an underdeveloped cerebral cortex with significantly reduced cortical thickness, albeit without abnormal cell density. Further in vitro neuronal culture demonstrated a significant reduction in dendritic spine density and affected synaptic maturation in Celf2 deficient mice, with no notable abnormalities in total neurite and axon length. RNA-seq and RIP-seq analysis of the cerebral cortex revealed differentially expressed genes post Celf2 gene knockout compared with the control group. Enrichment analysis highlighted significant enrichment in dendrite and synapse-related biological processes and pathways. Our study delineated the behavioral and neurodevelopmental phenotypes of Celf2, suggesting its potential involvement in autism through the regulation of target genes associated with dendritic spines and synapse development. Further research is needed to elucidate the specific mechanisms involved.
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Affiliation(s)
- Xinyu Duan
- Department of Pediatrics, Daping Hospital, Army Medical University, Chongqing, 400010, China
| | - Xiaoxia Peng
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Science, Central South University, Changsha, 410078, Hunan, China
| | - Xiangbin Jia
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Science, Central South University, Changsha, 410078, Hunan, China
| | - Senwei Tan
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Science, Central South University, Changsha, 410078, Hunan, China
| | - Hui Guo
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Science, Central South University, Changsha, 410078, Hunan, China
| | - Jieqiong Tan
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Science, Central South University, Changsha, 410078, Hunan, China.
- Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China.
- MOE Key Lab of Rare Pediatric Diseases, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China.
- NHC Key Laboratory of Birth Defect for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, 410078, Hunan, China.
| | - Zhangxue Hu
- Department of Pediatrics, Daping Hospital, Army Medical University, Chongqing, 400010, China.
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Guerrini R, Conti V. Epileptic encephalopathies and progressive neurodegeneration. Rev Neurol (Paris) 2024; 180:363-367. [PMID: 38582661 DOI: 10.1016/j.neurol.2024.03.004] [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: 02/28/2024] [Accepted: 03/25/2024] [Indexed: 04/08/2024]
Abstract
Developmental encephalopathies (DE), epileptic encephalopathies (EE) and developmental and epileptic encephalopathies (DEE) are overlapping neurodevelopmental disorders characterized by early-onset, often severe epileptic seizures, developmental delay, or regression and have multiple etiologies. Classical nosology in child neurology distinguished progressive and nonprogressive conditions. A progressive course with global cognitive worsening in DEE is usually attributed to severe seizures and electroencephalographic abnormalities whose deleterious effects interfere with developmental processes both in an apparently healthy brain and in an anatomically compromised one. Next generation sequencing and functional studies have helped identifying and characterizing clinical conditions, each with a broad spectrum of clinical and anatomic severity corresponding to a variable level of neurodegeneration, such that both a rapidly progressive course and considerably milder phenotypes with no obvious deterioration can be configured with mutations in the same gene. In this mini review, we present examples of genetic DEE that draw connections between neurodevelopmental and neurodegenerative disorders.
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Affiliation(s)
- R Guerrini
- Neuroscience Department, Meyer Children's Hospital IRCCS, Viale Pieraccini 24, 50139 Florence, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy.
| | - V Conti
- Neuroscience Department, Meyer Children's Hospital IRCCS, Viale Pieraccini 24, 50139 Florence, Italy
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3
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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Lorenzo DN, Edwards RJ, Slavutsky AL. Spectrins: molecular organizers and targets of neurological disorders. Nat Rev Neurosci 2023; 24:195-212. [PMID: 36697767 PMCID: PMC10598481 DOI: 10.1038/s41583-022-00674-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/26/2023]
Abstract
Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anastasia L Slavutsky
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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5
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Progressive Ataxia, Memory Impairments, and Seizure Episodes in Spna2 R1098Q Mouse Variant Affecting Alpha II Spectrin's Scaffold Stability. Brain Sci 2023; 13:brainsci13020261. [PMID: 36831804 PMCID: PMC9953789 DOI: 10.3390/brainsci13020261] [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: 01/03/2023] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
SPTAN1 spectrinopathies refer to a group of rare, inherited diseases associated with damage to non-erythrocytic α-II spectrin (α-II). They are linked to a range of mild to severe neuropathologies of the central and peripheral nervous systems, such as early infantile epileptic encephalopathy type 5, cerebellar ataxia, inherited peripheral neuropathy, and spastic paraplegia. Modeling human SPTAN1 encephalopathies in laboratory animals has been challenging partially because no haploinsufficiency-related phenotypes unfold in heterozygous Spna2 deficient mice nor stable transgenic lines of mice mimicking missense human SPTAN1 mutations have been created to date. Here, we assess the motor and memory performance of a dominant-negative murine Spna2 (SPTAN1) variant carrying a spontaneous point mutation replacing an arginine 1098 in the repeat 10th of α-II with the glutamine (R1098Q). By comparing groups of heterozygous R1098Q mice at different ages, we find evidence for progressive ataxia, and age-related deterioration of motor performance and muscle strength. We also document stress-induced, long-lasting seizure episodes of R1098Q mice and their poor performance in novel object recognition memory tests. Overall, we propose that the complexity of neuropathology-related phenotypes presented by the R1098Q mice recapitulates a number of symptoms observed in human patients carrying SPTAN1 mutations affecting α-II scaffold stability. This makes the R1098Q mice a valuable animal model for preclinical research.
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Sakata Y, Sano K, Aoki S, Saitsu H, Takanashi JI. Neurochemistry evaluated by MR spectroscopy in a patient with SPTAN1-related developmental and epileptic encephalopathy. Brain Dev 2022; 44:415-420. [PMID: 35219564 DOI: 10.1016/j.braindev.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Mutation of the SPTAN1 gene, which encodes α-fodrin (non-erythrocyte α-II spectrin), is one of the causes of developmental and epileptic encephalopathies (DEEs). SPTAN1-related DEE is radiologically characterized by cerebral atrophy, especially due to white matter volume reduction, hypomyelination, pontocerebellar hypoplasia, and a thin corpus callosum, however, no neurochemical analysis has been reported. CASE REPORT A Japanese infant female presented with severe psychomotor delay, tonic spasms, and visual impairment. Whole-exome sequencing revealed a de novo variant of the SPTAN1 gene, leading to a diagnosis of SPTAN1-related DEE. MR spectroscopy at ages 5 months, 11 months, and 1 year and 4 months revealed decreased N-acetylaspartate and choline-containing compounds, and increased glutamate or glutamine. CONCLUSION The decreased concentrations of N-acetylaspartate and choline-containing compounds may have resulted from neuroaxonal network dysfunction and hypomyelination, respectively. The increased glutamate or glutamine may have reflected a disrupted glutamate-glutamine cycle caused by dysfunction of exocytosis, in which α-fodrin plays an important role. MR spectroscopy revealed neurochemical derangement in SPTAN1-related DEE, which may be a possible pathomechanism and will be useful for its diagnosis.
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Affiliation(s)
- Yuka Sakata
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, Chiba, Japan
| | - Kentaro Sano
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, Chiba, Japan
| | - Shintaro Aoki
- Department of Biochemistry, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Jun-Ichi Takanashi
- Department of Pediatrics, Tokyo Women's Medical University Yachiyo Medical Center, Chiba, Japan.
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7
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Li S, Liu T, Li K, Bai X, Xi K, Chai X, Mi L, Li J. Spectrins and human diseases. Transl Res 2022; 243:78-88. [PMID: 34979321 DOI: 10.1016/j.trsl.2021.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/18/2022]
Abstract
Spectrin, as one of the major components of a plasma membrane-associated cytoskeleton, is a cytoskeletal protein composed of the modular structure of α and β subunits. The spectrin-based skeleton is essential for preserving the integrity and mechanical characteristics of the cell membrane. Moreover, spectrin regulates a variety of cell processes including cell apoptosis, cell adhesion, cell spreading, and cell cycle. Dysfunction of spectrins is implicated in various human diseases including hemolytic anemia, neurodegenerative diseases, ataxia, heart diseases, and cancers. Here, we briefly discuss spectrins function as well as the clinical manifestations and currently known molecular mechanisms of human diseases related to spectrins, highlighting that strategies for targeting regulation of spectrins function may provide new avenues for therapeutic intervention for these diseases.
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Affiliation(s)
- Shan Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Ting Liu
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kejing Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xinyi Bai
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kewang Xi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xiaojing Chai
- Central Laboratory, The First Hospital of Lanzhou University, Gansu, China
| | - Leyuan Mi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China; Clinical Laboratory Center, Gansu Provincial Maternity and Child Care Hospital, Gansu, China
| | - Juan Li
- Gansu Key Laboratory of Genetic Study of Hematopathy, The First Hospital of Lanzhou University, Gansu, China; Central Laboratory, The First Hospital of Lanzhou University, Gansu, China.
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8
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Cui X, Hu D, Lin P, Cao J, Lai X, Wang T, Jiang T, Gao F. Deep feature fusion based childhood epilepsy syndrome classification from electroencephalogram. Neural Netw 2022; 150:313-325. [DOI: 10.1016/j.neunet.2022.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 01/11/2022] [Accepted: 03/07/2022] [Indexed: 12/01/2022]
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9
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Van de Vondel L, De Winter J, Beijer D, Coarelli G, Wayand M, Palvadeau R, Pauly MG, Klein K, Rautenberg M, Guillot-Noël L, Deconinck T, Vural A, Ertan S, Dogu O, Uysal H, Brankovic V, Herzog R, Brice A, Durr A, Klebe S, Stock F, Bischoff AT, Rattay TW, Sobrido MJ, De Michele G, De Jonghe P, Klopstock T, Lohmann K, Zanni G, Santorelli FM, Timmerman V, Haack TB, Züchner S, Schüle R, Stevanin G, Synofzik M, Basak AN, Baets J. De Novo and Dominantly Inherited SPTAN1 Mutations Cause Spastic Paraplegia and Cerebellar Ataxia. Mov Disord 2022; 37:1175-1186. [PMID: 35150594 DOI: 10.1002/mds.28959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Pathogenic variants in SPTAN1 have been linked to a remarkably broad phenotypical spectrum. Clinical presentations include epileptic syndromes, intellectual disability, and hereditary motor neuropathy. OBJECTIVES We investigated the role of SPTAN1 variants in rare neurological disorders such as ataxia and spastic paraplegia. METHODS We screened 10,000 NGS datasets across two international consortia and one local database, indicative of the level of international collaboration currently required to identify genes causative for rare disease. We performed in silico modeling of the identified SPTAN1 variants. RESULTS We describe 22 patients from 14 families with five novel SPTAN1 variants. Of six patients with cerebellar ataxia, four carry a de novo SPTAN1 variant and two show a sporadic inheritance. In this group, one variant (p.Lys2083del) is recurrent in four patients. Two patients have novel de novo missense mutations (p.Arg1098Cys, p.Arg1624Cys) associated with cerebellar ataxia, in one patient accompanied by intellectual disability and epilepsy. We furthermore report a recurrent missense mutation (p.Arg19Trp) in 15 patients with spastic paraplegia from seven families with a dominant inheritance pattern in four and a de novo origin in one case. One further patient carrying a de novo missense mutation (p.Gln2205Pro) has a complex spastic ataxic phenotype. Through protein modeling we show that mutated amino acids are located at crucial interlinking positions, interconnecting the three-helix bundle of a spectrin repeat. CONCLUSIONS We show that SPTAN1 is a relevant candidate gene for ataxia and spastic paraplegia. We suggest that for the mutations identified in this study, disruption of the interlinking of spectrin helices could be a key feature of the pathomechanism. © 2022 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Liedewei Van de Vondel
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Jonathan De Winter
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Dr John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Giulia Coarelli
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Melanie Wayand
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - Robin Palvadeau
- Koc University, School of Medicine, Suna and Inan Kirac Foundation, Istanbul, Turkey
| | - Martje G Pauly
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany.,Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Katrin Klein
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
| | - Maren Rautenberg
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
| | - Léna Guillot-Noël
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Tine Deconinck
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem, Belgium
| | - Atay Vural
- School of Medicine, Department of Neurology, Koc University, Istanbul, Turkey
| | - Sibel Ertan
- School of Medicine, Department of Neurology, Koc University, Istanbul, Turkey
| | - Okan Dogu
- Department of Neurology, School of Medicine, Mersin University, Mersin, Turkey
| | - Hilmi Uysal
- Department of Neurology, School of Medicine, Akdeniz University, Antalya, Turkey
| | - Vesna Brankovic
- Clinic for Child Neurology and Psychiatry, University of Belgrade, Belgrade, Serbia
| | - Rebecca Herzog
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany
| | - Alexis Brice
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Alexandra Durr
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Stephan Klebe
- Department of Neurology, University Hospital Essen, Essen, Germany
| | - Friedrich Stock
- Institute of Human Genetics, University Hospital Essen, Essen, Germany
| | | | - Tim W Rattay
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - María-Jesús Sobrido
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Santiago de Compostela, Spain.,Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Peter De Jonghe
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur-Institute, LMU Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Vincent Timmerman
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany.,Centre for Rare Diseases, University of Tübingen, Tübingen, Germany
| | - Stephan Züchner
- Dr John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - Giovanni Stevanin
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France.,Paris Sciences Lettres Research University, Ecole Pratique des Hautes Etudes, Paris, France
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - A Nazli Basak
- Koc University, School of Medicine, Suna and Inan Kirac Foundation, Istanbul, Turkey
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
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10
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Shono K, Enomoto Y, Tsurusaki Y, Kumaki T, Masuno M, Kurosawa K. Further delineation of SET-related intellectual disability syndrome. Am J Med Genet A 2022; 188:1595-1599. [PMID: 35122673 DOI: 10.1002/ajmg.a.62681] [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: 06/19/2021] [Revised: 01/09/2022] [Accepted: 01/15/2022] [Indexed: 11/11/2022]
Abstract
A loss-of-function mutation of SET causes nonsyndromic intellectual disability, often associated with mild facial dysmorphic features, including plagiocephaly, facial asymmetry, broad and high forehead, a wide mouth, and a prominent mandible. We report a male individual with a 2.0 Mb deletion within 9q34.11, involving SET and SPTAN1, but not STXBP1. Among the genes with a high probability of being loss-of-function intolerant in the deletion interval, only SPTAN1 and SET had haploinsufficiency score (%HI) <10, indicating a high likelihood of haploinsufficiency. Pathogenic variants in SPTAN1 are responsible for early-onset epileptic encephalopathy by exerting a dominant-negative effect. However, whether haploinsufficiency of SPTAN1 alone also causes the severe phenotype remained unknown. SET is a regulator of cell differentiation in early human development and a component of the inhibitor of histone acetyltransferases complex. Therefore, combining the previously reported patients, our patient delineated the phenotypic spectrum of SET-related nonsyndromic intellectual disability with mild facial dysmorphism.
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Affiliation(s)
- Kenta Shono
- Division of Medical Genetics, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Yumi Enomoto
- Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Yoshinori Tsurusaki
- Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Tatsuro Kumaki
- Division of Medical Genetics, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Mitsuo Masuno
- Genetic Counseling Program, Graduate School of Health and Welfare, Kawasaki University of Medical Welfare, Kurashiki, Japan
| | - Kenji Kurosawa
- Division of Medical Genetics, Kanagawa Children's Medical Center, Yokohama, Japan
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11
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Luongo-Zink C, Ammons C, Al-Ramadhani R, Logan R, Ono K, Bhalla S, Kheder A, Marcus D, Drane D, Bearden D. Longitudinal neurodevelopmental profile of a pediatric patient with de novo SPTAN1, epilepsy, and left hippocampal sclerosis. Epilepsy Behav Rep 2022; 19:100550. [PMID: 35620303 PMCID: PMC9126767 DOI: 10.1016/j.ebr.2022.100550] [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: 12/07/2021] [Revised: 04/23/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022] Open
Abstract
We present the first longitudinal study of neuropsychological functioning in a pediatric patient with SPTAN1. To our knowledge we report the first case of SPTAN1 heterozygosity in a patient with MTLE due to HS. This case is the first to show that lisdexamfetamine dimesylate improved attention, behavior, and school performance in a patient with heterozygous SPTAN1 variant.
Pathogenic variants in SPTAN1 result in abnormal neurodevelopment but limited information is available on the spectrum of neurodevelopmental profiles associated with variations in this gene. We present novel data collected at two time points over a three-year period in a nine-year-old patient with heterozygous de novo SPTAN1 variant, drug-resistant epilepsy, and left hippocampal sclerosis. Across evaluations, our patient’s performance was highly variable, ranging from below age expectation to within age-expected range. The patient exhibited relative cognitive strengths at both time points on verbal-expressive tasks. Weaknesses were seen in her attention, executive function, psychomotor processing speed, fine motor, visual-motor integration, and social skills. Memory findings were consistent those associated with left hippocampal sclerosis. Evaluations resulted in diagnoses including attention deficit hyperactivity disorder and autism spectrum disorder.
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Affiliation(s)
- C. Luongo-Zink
- William James College, Newton, MA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - C. Ammons
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - R. Al-Ramadhani
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - R. Logan
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - K.E. Ono
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - S. Bhalla
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - A. Kheder
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - D.J. Marcus
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - D.L. Drane
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - D.J. Bearden
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
- Corresponding author at: Center for Advanced Pediatrics, Children’s Healthcare of Atlanta, 1400 Tullie Rd. NE, Ste. 430, Atlanta, GA 30329, USA.
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Skrzymowska J, Zalas M, Goszczyński TM, Miazek A. An alpha II spectrin mutant peptide with unstable scaffold structure and increased sensitivity to calpain cleavage. Biochem Biophys Res Commun 2021; 581:68-73. [PMID: 34656850 DOI: 10.1016/j.bbrc.2021.10.021] [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: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
A spontaneous missense mutation in the alpha II spectrin (αII) gene, replacing a highly conserved arginine 1098 with the glutamine (R1098Q), causes progressive neurodegeneration in heterozygous mutant mice. The molecular mechanism underlying this phenotype is unknown but the accumulation of 150kD αII breakdown products in brains of homozygous mutant embryos suggests an imbalance in the substrate level control of αII cleavage by calpains. This is further supported by in silico simulation predicting unmasked calpain target site and increased spectrin scaffold bending and flexibility of R1098Q mutant peptide. Here, using spectroscopic and in situ enzymatic techniques, we aimed at obtaining direct experimental support for the impact of R1098Q mutation on the αII stability and its propensity for calpain-mediated degradation. Thermal circular dichroism analyses performed on recombinant wildtype and R1098Q mutant αII peptides, composed of spectrin repeat 9-10 revealed that although both had very similar secondary structure contents, thermal stability curve profiles varied and the observed midpoint of the unfolding transition (Tm) was 5.5 °C lower for the R1098Q peptide. Yet, the dynamic light scattering profiles of both peptides closely overlapped, implying the same thermal propensity to aggregate. Calpain digestion of plate-bound αII peptides with and without added calmodulin revealed an enhancement of the R1098Q peptide digestion rate relative to WT control. In summary, these results support the unstable scaffold structure of the R1098Q peptide as contributing to its enhanced intrinsic sensitivity to calpain and suggest physiologic relevance of a proper calpain/spectrin balance in preventing neurodegeneration.
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Affiliation(s)
- Joanna Skrzymowska
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Michał Zalas
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Tomasz M Goszczyński
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Arkadiusz Miazek
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland.
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Marco Hernández AV, Caro A, Montoya Filardi A, Tomás Vila M, Monfort S, Beseler Soto B, Nieto-Barceló JJ, Martínez F. Extending the clinical phenotype of SPTAN1: From DEE5 to migraine, epilepsy, and subependymal heterotopias without intellectual disability. Am J Med Genet A 2021; 188:147-159. [PMID: 34590414 DOI: 10.1002/ajmg.a.62507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/08/2022]
Abstract
Mutations in SPTAN1 gene, encoding the nonerythrocyte αII-spectrin, are responsible for a severe developmental and epileptic encephalopathy (DEE5) and a wide spectrum of neurodevelopmental disorders, as epilepsy with or without intellectual disability (ID) or ID with cerebellar syndrome. A certain genotype-phenotype correlation has been proposed according to the type and location of the mutation. Herein, we report three novel cases with de novo SPTAN1 mutations, one of them associated to a mild phenotype not previously described. They range from (1) severe developmental encephalopathy with ataxia and a mild cerebellar atrophy, without epilepsy; (2) moderate intellectual disability, severe language delay, ataxia and tremor; (3) normal intelligence, chronic migraine, and generalized tonic-clonic seizures. Remarkably, all these patients showed brain MRI abnormalities, being of special interest the subependymal heterotopias detected in the latter patient. Thus we extend the SPTAN1-related phenotypic spectrum, both in its radiological and clinical involvement. Furthermore, after systematic analysis of all the patients so far reported, we noted an excess of male versus female patients (20:9, p = 0.04), more pronounced among the milder phenotypes. Consequently, some protection factor might be suspected among female carriers, which if confirmed should be considered when establishing the pathogenicity of milder genetic variants in this gene.
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Affiliation(s)
- Ana Victoria Marco Hernández
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Neuropediatrics Section, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Alfonso Caro
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | | | - Miguel Tomás Vila
- Neuropediatrics Section, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Sandra Monfort
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Beatriz Beseler Soto
- Neuropediatrics Section, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | | | - Francisco Martínez
- Genetics Unit, Hospital Universitari i Politècnic La Fe, Valencia, Spain
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SPTAN1 variants likely cause autosomal recessive complicated hereditary spastic paraplegia. J Hum Genet 2021; 67:165-168. [PMID: 34526651 DOI: 10.1038/s10038-021-00975-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/09/2022]
Abstract
Heterozygous mutations in SPTAN1 are associated with a broad phenotypical spectrum ranging from axonal neuropathy phenotypes to neurodevelopmental phenotypes with or without epilepsy. Recently, biallelic mutations in SPTAN1 were reported as a potential cause of autosomal recessive pure hereditary spastic paraplegia (HSP). However, no further HSP cases with biallelic SPTAN1 mutations have been reported. Herein, we report the clinical and genetic findings of a patient with complicated HSP likely caused by a novel homozygous SPTAN1 mutation. A patient with complicated HSP from a consanguineous family was recruited. The proband underwent detailed neurological examinations. Homozygosity mapping was performed in the proband and her healthy sister. Whole exome sequencing was performed in the proband. Our patient had early onset motor symptoms with upper motor neuron paralysis and intellectual disability, which is compatible with complicated HSP. Genetic analysis identified a rare homozygous missense mutation in SPTAN1 (c.4162A>G, p.I1388V), which was predicted to be deleterious by in silico tools. Her healthy parents and sister all carried the heterozygous mutation. Our results provided further support for the association of biallelic SPTAN1 variants with HSP and suggested that screening for the SPTAN1 gene should be considered not only in patients with pure HSP but also in patients with complicated HSP.
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15
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Tremor-like subcortical myoclonus in STXBP1 encephalopathy. Eur J Paediatr Neurol 2021; 34:62-66. [PMID: 34392114 DOI: 10.1016/j.ejpn.2021.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/26/2021] [Accepted: 06/22/2021] [Indexed: 01/28/2023]
Abstract
The phenotypic spectrum of STXBP1-related encephalopathy ranges from infantile epileptic encephalopathy to intellectual disability with nonsyndromic or absent epilepsy. Although being frequently reported, the tremor associated with STXBP1 has not been fully characterized to date. The aim of our study was to describe it. We recruited patients with intellectual disability due to STXBP1 variants, regardless of their epileptic phenotype, who had tremor at examination and who underwent neurophysiological testing including polymyographic registration of upper limbs muscles activity at rest, during posture maintenance and action. Six patients met the inclusion criteria over four years. Clinically, all had a postural and action distal tremor increased by emotions. Neurophysiological recordings showed a specific myoclonus pattern and were highly suggestive of a subcortical generator. The tremor-like observed in STXBP1 encephalopathy is due to a subcortical pseudo-rhythmic myoclonus.
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16
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Fujitani M, Otani Y, Miyajima H. Pathophysiological Roles of Abnormal Axon Initial Segments in Neurodevelopmental Disorders. Cells 2021; 10:2110. [PMID: 34440880 PMCID: PMC8392614 DOI: 10.3390/cells10082110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 11/17/2022] Open
Abstract
The 20-60 μm axon initial segment (AIS) is proximally located at the interface between the axon and cell body. AIS has characteristic molecular and structural properties regulated by the crucial protein, ankyrin-G. The AIS contains a high density of Na+ channels relative to the cell body, which allows low thresholds for the initiation of action potential (AP). Molecular and physiological studies have shown that the AIS is also a key domain for the control of neuronal excitability by homeostatic mechanisms. The AIS has high plasticity in normal developmental processes and pathological activities, such as injury, neurodegeneration, and neurodevelopmental disorders (NDDs). In the first half of this review, we provide an overview of the molecular, structural, and ion-channel characteristics of AIS, AIS regulation through axo-axonic synapses, and axo-glial interactions. In the second half, to understand the relationship between NDDs and AIS, we discuss the activity-dependent plasticity of AIS, the human mutation of AIS regulatory genes, and the pathophysiological role of an abnormal AIS in NDD model animals and patients. We propose that the AIS may provide a potentially valuable structural biomarker in response to abnormal network activity in vivo as well as a new treatment concept at the neural circuit level.
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Affiliation(s)
- Masashi Fujitani
- Department of Anatomy and Neuroscience, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-shi 693-8501, Shimane, Japan; (Y.O.); (H.M.)
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17
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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18
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Cousin MA, Creighton BA, Breau KA, Spillmann RC, Torti E, Dontu S, Tripathi S, Ajit D, Edwards RJ, Afriyie S, Bay JC, Harper KM, Beltran AA, Munoz LJ, Falcon Rodriguez L, Stankewich MC, Person RE, Si Y, Normand EA, Blevins A, May AS, Bier L, Aggarwal V, Mancini GMS, van Slegtenhorst MA, Cremer K, Becker J, Engels H, Aretz S, MacKenzie JJ, Brilstra E, van Gassen KLI, van Jaarsveld RH, Oegema R, Parsons GM, Mark P, Helbig I, McKeown SE, Stratton R, Cogne B, Isidor B, Cacheiro P, Smedley D, Firth HV, Bierhals T, Kloth K, Weiss D, Fairley C, Shieh JT, Kritzer A, Jayakar P, Kurtz-Nelson E, Bernier RA, Wang T, Eichler EE, van de Laar IMBH, McConkie-Rosell A, McDonald MT, Kemppainen J, Lanpher BC, Schultz-Rogers LE, Gunderson LB, Pichurin PN, Yoon G, Zech M, Jech R, Winkelmann J, Beltran AS, Zimmermann MT, Temple B, Moy SS, Klee EW, Tan QKG, Lorenzo DN. Pathogenic SPTBN1 variants cause an autosomal dominant neurodevelopmental syndrome. Nat Genet 2021; 53:1006-1021. [PMID: 34211179 PMCID: PMC8273149 DOI: 10.1038/s41588-021-00886-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 05/14/2021] [Indexed: 12/22/2022]
Abstract
SPTBN1 encodes βII-spectrin, the ubiquitously expressed β-spectrin that forms micrometer-scale networks associated with plasma membranes. Mice deficient in neuronal βII-spectrin have defects in cortical organization, developmental delay and behavioral deficiencies. These phenotypes, while less severe, are observed in haploinsufficient animals, suggesting that individuals carrying heterozygous SPTBN1 variants may also show measurable compromise of neural development and function. Here we identify heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures; behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features. We show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics. Our studies define SPTBN1 variants as the genetic basis of a neurodevelopmental syndrome, expand the set of spectrinopathies affecting the brain and underscore the critical role of βII-spectrin in the central nervous system.
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Affiliation(s)
- Margot A Cousin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA.
| | - Blake A Creighton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Keith A Breau
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rebecca C Spillmann
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | | | - Sruthi Dontu
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Swarnendu Tripathi
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Deepa Ajit
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Simone Afriyie
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Julia C Bay
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kathryn M Harper
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alvaro A Beltran
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lorena J Munoz
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Liset Falcon Rodriguez
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Yue Si
- GeneDx, Gaithersburg, MD, USA
| | | | | | - Alison S May
- Department of Neurology, Columbia University, New York, NY, USA
| | - Louise Bier
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Vimla Aggarwal
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
- Laboratory of Personalized Genomic Medicine, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | | | - Kirsten Cremer
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Jessica Becker
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Hartmut Engels
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | | | - Eva Brilstra
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Paul Mark
- Spectrum Health Medical Genetics, Grand Rapids, MI, USA
| | - Ingo Helbig
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Sarah E McKeown
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert Stratton
- Genetics, Driscoll Children's Hospital, Corpus Christi, TX, USA
| | - Benjamin Cogne
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Pilar Cacheiro
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Damian Smedley
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Helen V Firth
- Department of Clinical Genetics, Cambridge University Hospitals, Cambridge, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Kloth
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Deike Weiss
- Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cecilia Fairley
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Joseph T Shieh
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Amy Kritzer
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | | | - Evangeline Kurtz-Nelson
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Tianyun Wang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Allyn McConkie-Rosell
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Marie T McDonald
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Jennifer Kemppainen
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Brendan C Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Laura E Schultz-Rogers
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Lauren B Gunderson
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Pavel N Pichurin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Grace Yoon
- Divisions of Clinical/Metabolic Genetics and Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
| | - Robert Jech
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany
- Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Adriana S Beltran
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael T Zimmermann
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brenda Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sheryl S Moy
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Queenie K-G Tan
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Damaris N Lorenzo
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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19
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Rosenfeld JA, Xiao R, Bekheirnia MR, Kanani F, Parker MJ, Koenig MK, van Haeringen A, Ruivenkamp C, Rosmaninho-Salgado J, Almeida PM, Sá J, Basto JP, Palen E, Oetjens KF, Burrage LC, Xia F, Liu P, Eng CM, Yang Y, Posey JE, Lee BH. Heterozygous variants in SPTBN1 cause intellectual disability and autism. Am J Med Genet A 2021; 185:2037-2045. [PMID: 33847457 PMCID: PMC11182376 DOI: 10.1002/ajmg.a.62201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 02/26/2021] [Accepted: 03/24/2021] [Indexed: 11/09/2022]
Abstract
Spectrins are common components of cytoskeletons, binding to cytoskeletal elements and the plasma membrane, allowing proper localization of essential membrane proteins, signal transduction, and cellular scaffolding. Spectrins are assembled from α and β subunits, encoded by SPTA1 and SPTAN1 (α) and SPTB, SPTBN1, SPTBN2, SPTBN4, and SPTBN5 (β). Pathogenic variants in various spectrin genes are associated with erythroid cell disorders (SPTA1, SPTB) and neurologic disorders (SPTAN1, SPTBN2, and SPTBN4), but no phenotypes have been definitively associated with variants in SPTBN1 or SPTBN5. Through exome sequencing and case matching, we identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities). Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset. Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis. Our findings support the essential roles of SPTBN1 in human neurodevelopment and expand the knowledge of human spectrinopathy disorders.
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Affiliation(s)
- Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Rui Xiao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Mir Reza Bekheirnia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Renal Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Farah Kanani
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Michael J. Parker
- The Wellcome Centre for Ethics and Humanities/Ethox Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Mary K. Koenig
- Department of Pediatrics, University of Texas Health Science Center, Houston, Texas, 77030, USA
| | - Arie van Haeringen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Joana Rosmaninho-Salgado
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Pedro M. Almeida
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joaquim Sá
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Jorge Pinto Basto
- Molecular Diagnostics and Clinical Genomics, CGC Genetics, Porto, Portugal
| | - Emily Palen
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Kathryn F. Oetjens
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Texas Children’s Hospital, Houston, Texas, 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Christine M. Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | | | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Brendan H. Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
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20
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Dong HL, Chen L, Wu ZY. A novel de novo SPTAN1 nonsense variant causes hereditary motor neuropathy in a Chinese family. Brain 2021; 144:e11. [PMID: 33578420 DOI: 10.1093/brain/awaa357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- Hai-Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Lei Chen
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
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21
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Miazek A, Zalas M, Skrzymowska J, Bogin BA, Grzymajło K, Goszczynski TM, Levine ZA, Morrow JS, Stankewich MC. Age-dependent ataxia and neurodegeneration caused by an αII spectrin mutation with impaired regulation of its calpain sensitivity. Sci Rep 2021; 11:7312. [PMID: 33790315 PMCID: PMC8012654 DOI: 10.1038/s41598-021-86470-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 03/15/2021] [Indexed: 12/15/2022] Open
Abstract
The neuronal membrane-associated periodic spectrin skeleton (MPS) contributes to neuronal development, remodeling, and organization. Post-translational modifications impinge on spectrin, the major component of the MPS, but their role remains poorly understood. One modification targeting spectrin is cleavage by calpains, a family of calcium-activated proteases. Spectrin cleavage is regulated by activated calpain, but also by the calcium-dependent binding of calmodulin (CaM) to spectrin. The physiologic significance of this balance between calpain activation and substrate-level regulation of spectrin cleavage is unknown. We report a strain of C57BL/6J mice harboring a single αII spectrin point mutation (Sptan1 c.3293G > A:p.R1098Q) with reduced CaM affinity and intrinsically enhanced sensitivity to calpain proteolysis. Homozygotes are embryonic lethal. Newborn heterozygotes of either gender appear normal, but soon develop a progressive ataxia characterized biochemically by accelerated calpain-mediated spectrin cleavage and morphologically by disruption of axonal and dendritic integrity and global neurodegeneration. Molecular modeling predicts unconstrained exposure of the mutant spectrin's calpain-cleavage site. These results reveal the critical importance of substrate-level regulation of spectrin cleavage for the maintenance of neuronal integrity. Given that excessive activation of calpain proteases is a common feature of neurodegenerative disease and traumatic encephalopathy, we propose that damage to the spectrin MPS may contribute to the neuropathology of many disorders.
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Affiliation(s)
- Arkadiusz Miazek
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland
- Department of Biochemistry and Molecular Biology, Wroclaw University of Environmental and Life Sciences, Norwida 31, 50-375, Wrocław, Poland
| | - Michał Zalas
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland
| | - Joanna Skrzymowska
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland
| | - Bryan A Bogin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Krzysztof Grzymajło
- Department of Biochemistry and Molecular Biology, Wroclaw University of Environmental and Life Sciences, Norwida 31, 50-375, Wrocław, Poland
| | - Tomasz M Goszczynski
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wrocław, Poland
| | - Zachary A Levine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, LH108, New Haven, CT, 06520, USA
| | - Jon S Morrow
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, LH108, New Haven, CT, 06520, USA.
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA.
| | - Michael C Stankewich
- Department of Pathology, Yale University School of Medicine, 310 Cedar Street, LH108, New Haven, CT, 06520, USA.
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22
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Morrow JS, Stankewich MC. The Spread of Spectrin in Ataxia and Neurodegenerative Disease. JOURNAL OF EXPERIMENTAL NEUROLOGY 2021; 2:131-139. [PMID: 34528024 PMCID: PMC8439443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Experimental and hereditary defects in the ubiquitous scaffolding proteins of the spectrin gene family cause an array of neuropathologies. Most recognized are ataxias caused by missense, deletions, or truncations in the SPTBN2 gene that encodes beta III spectrin. Such mutations disrupt the organization of post-synaptic receptors, their active transport through the secretory pathway, and the organization and dynamics of the actin-based neuronal skeleton. Similar mutations in SPTAN1 that encodes alpha II spectrin cause severe and usually lethal neurodevelopmental defects including one form of early infantile epileptic encephalopathy type 5 (West syndrome). Defects in these and other spectrins are implicated in degenerative and psychiatric conditions. In recent published work, we describe in mice a novel variant of alpha II spectrin that results in a progressive ataxia with widespread neurodegenerative change. The action of this variant is distinct, in that rather than disrupting a constitutive ligand-binding function of spectrin, the mutation alters its response to calcium and calmodulin-regulated signaling pathways including its response to calpain activation. As such, it represents a novel spectrinopathy that targets a key regulatory pathway where calcium and tyrosine kinase signals converge. Here we briefly discuss the various roles of spectrin in neuronal processes and calcium activated regulatory inputs that control its participation in neuronal growth, organization, and remodeling. We hypothesize that damage to the neuronal spectrin scaffold may be a common final pathway in many neurodegenerative disorders. Targeting the pathways that regulate spectrin function may thus offer novel avenues for therapeutic intervention.
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Affiliation(s)
- Jon S. Morrow
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA,Molecular & Cellular Developmental Biology, Yale University, New Haven, CT 06520, USA,Correspondence should be addressed to Jon S. Morrow; , Michael Stankewich;
| | - Michael C. Stankewich
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA,Correspondence should be addressed to Jon S. Morrow; , Michael Stankewich;
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23
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Ylikallio E, Ritari N, Sainio M, Toppila J, Kivirikko S, Tyynismaa H, Auranen M, Isohanni P. De novo SPTAN1 mutation in axonal sensorimotor neuropathy and developmental disorder. Brain 2020; 143:e104. [DOI: 10.1093/brain/awaa344] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Niina Ritari
- Neuropsychology, New Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Markus Sainio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jussi Toppila
- Department of Clinical Neurophysiology, Medical Imaging Center, Helsinki University Central Hospital, Helsinki Finland
| | - Sirpa Kivirikko
- Department of Clinical Genetics, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Department of Medical and Clinical Genetics, University of Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, University of Helsinki, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Mari Auranen
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Pirjo Isohanni
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Neurology, New Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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24
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Akamine S, Okuzono S, Yamamoto H, Setoyama D, Sagata N, Ohgidani M, Kato TA, Ishitani T, Kato H, Masuda K, Matsushita Y, Ono H, Ishizaki Y, Sanefuji M, Saitsu H, Matsumoto N, Kang D, Kanba S, Nakabeppu Y, Sakai Y, Ohga S. GNAO1 organizes the cytoskeletal remodeling and firing of developing neurons. FASEB J 2020; 34:16601-16621. [PMID: 33107105 DOI: 10.1096/fj.202001113r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/03/2020] [Accepted: 10/13/2020] [Indexed: 01/03/2023]
Abstract
Developmental and epileptic encephalopathy (DEE) represents a group of neurodevelopmental disorders characterized by infantile-onset intractable seizures and unfavorable prognosis of psychomotor development. To date, hundreds of genes have been linked to the onset of DEE. GNAO1 is a DEE-associated gene encoding the alpha-O1 subunit of guanine nucleotide-binding protein (GαO ). Despite the increasing number of reported children with GNAO1 encephalopathy, the molecular mechanisms underlying their neurodevelopmental phenotypes remain elusive. We herein present that co-immunoprecipitation and mass spectrometry analyses identified another DEE-associated protein, SPTAN1, as an interacting partner of GαO . Silencing of endogenous Gnao1 attenuated the neurite outgrowth and calcium-dependent signaling. Inactivation of GNAO1 in human-induced pluripotent stem cells gave rise to anomalous brain organoids that only weakly expressed SPTAN1 and Ankyrin-G. Furthermore, GNAO1-deficient organoids failed to conduct synchronized firing to adjacent neurons. These data indicate that GαO and other DEE-associated proteins organize the cytoskeletal remodeling and functional polarity of neurons in the developing brain.
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Affiliation(s)
- Satoshi Akamine
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Sayaka Okuzono
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Yamamoto
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Daiki Setoyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Noriaki Sagata
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masahiro Ohgidani
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takahiro A Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tohru Ishitani
- Division of Integrated Signaling Systems, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.,Department of Homeostatic Regulation, Division of Cellular and Molecular Biology. Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Hiroki Kato
- Division of Oral Biological Sciences, Department of Molecular Cell Biology and Oral Anatomy, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Keiji Masuda
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yuki Matsushita
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroaki Ono
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshito Ishizaki
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masafumi Sanefuji
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigenobu Kanba
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Yasunari Sakai
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shouichi Ohga
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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25
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A three-year follow-up study evaluating clinical utility of exome sequencing and diagnostic potential of reanalysis. NPJ Genom Med 2020; 5:37. [PMID: 32963807 PMCID: PMC7484757 DOI: 10.1038/s41525-020-00144-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/14/2020] [Indexed: 01/05/2023] Open
Abstract
Exome sequencing (ES) has become one of the important diagnostic tools in clinical genetics with a reported diagnostic rate of 25–58%. Many studies have illustrated the diagnostic and immediate clinical impact of ES. However, up to 75% of individuals remain undiagnosed and there is scarce evidence supporting clinical utility beyond a follow-up period of >1 year. This is a 3-year follow-up analysis to our previous publication by Mak et al. (NPJ Genom. Med. 3:19, 2018), to evaluate the long-term clinical utility of ES and the diagnostic potential of exome reanalysis. The diagnostic yield of the initial study was 41% (43/104). Exome reanalysis in 46 undiagnosed individuals has achieved 12 new diagnoses. The additional yield compared with the initial analysis was at least 12% (increased from 41% to at least 53%). After a median follow-up period of 3.4 years, change in clinical management was observed in 72.2% of the individuals (26/36), leading to positive change in clinical outcome in four individuals (11%). There was a minimum healthcare cost saving of HKD$152,078 (USD$19,497; €17,282) annually for these four individuals. There were a total of six pregnancies from five families within the period. Prenatal diagnosis was performed in four pregnancies; one fetus was affected and resulted in termination. None of the parents underwent preimplantation genetic diagnosis. This 3-year follow-up study demonstrated the long-term clinical utility of ES at individual, familial and health system level, and the promising diagnostic potential of subsequent reanalysis. This highlights the benefits of implementing ES and regular reanalysis in the clinical setting.
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26
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Abstract
Fodrin and its erythroid cell-specific isoform spectrin are actin-associated fibrous proteins that play crucial roles in the maintenance of structural integrity in mammalian cells, which is necessary for proper cell function. Normal cell morphology is altered in diseases such as various cancers and certain neuronal disorders. Fodrin and spectrin are two-chain (αβ) molecules that are encoded by paralogous genes and share many features but also demonstrate certain differences. Fodrin (in humans, typically a heterodimer of the products of the SPTAN1 and SPTBN1 genes) is expressed in nearly all cell types and is especially abundant in neuronal tissues, whereas spectrin (in humans, a heterodimer of the products of the SPTA1 and SPTB1 genes) is expressed almost exclusively in erythrocytes. To fulfill a role in such a variety of different cell types, it was anticipated that fodrin would need to be a more versatile scaffold than spectrin. Indeed, as summarized here, domains unique to fodrin and its regulation by Ca2+, calmodulin, and a variety of posttranslational modifications (PTMs) endow fodrin with additional specific functions. However, how fodrin structural variations and misregulated PTMs may contribute to the etiology of various cancers and neurodegenerative diseases needs to be further investigated.
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27
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Beijer D, Deconinck T, De Bleecker JL, Dotti MT, Malandrini A, Urtizberea JA, Zulaica M, López de Munain A, Asselbergh B, De Jonghe P, Baets J. Nonsense mutations in alpha-II spectrin in three families with juvenile onset hereditary motor neuropathy. Brain 2020; 142:2605-2616. [PMID: 31332438 DOI: 10.1093/brain/awz216] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/25/2019] [Accepted: 05/28/2019] [Indexed: 01/09/2023] Open
Abstract
Distal hereditary motor neuropathies are a rare subgroup of inherited peripheral neuropathies hallmarked by a length-dependent axonal degeneration of lower motor neurons without significant involvement of sensory neurons. We identified patients with heterozygous nonsense mutations in the αII-spectrin gene, SPTAN1, in three separate dominant hereditary motor neuropathy families via next-generation sequencing. Variable penetrance was noted for these mutations in two of three families, and phenotype severity differs greatly between patients. The mutant mRNA containing nonsense mutations is broken down by nonsense-mediated decay and leads to reduced protein levels in patient cells. Previously, dominant-negative αII-spectrin gene mutations were described as causal in a spectrum of epilepsy phenotypes.
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Affiliation(s)
- Danique Beijer
- Neurogenetics Group, Center for Molecular Neurology, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | - Tine Deconinck
- Neurogenetics Group, Center for Molecular Neurology, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | | | - Maria Teresa Dotti
- Department of Medicine, Surgery and Neuroscience, University of Siena, Italy
| | | | | | - Miren Zulaica
- Neuroscience Area, Institute Biodonostia, Hospital Universitario Donostia, San Sebastian, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Madrid, Spain
| | - Adolfo López de Munain
- Neuroscience Area, Institute Biodonostia, Hospital Universitario Donostia, San Sebastian, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Madrid, Spain
| | - Bob Asselbergh
- VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Antwerp, Belgium
| | - Peter De Jonghe
- Neurogenetics Group, Center for Molecular Neurology, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
| | - Jonathan Baets
- Neurogenetics Group, Center for Molecular Neurology, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
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28
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Lorenzo DN. Cargo hold and delivery: Ankyrins, spectrins, and their functional patterning of neurons. Cytoskeleton (Hoboken) 2020; 77:129-148. [PMID: 32034889 DOI: 10.1002/cm.21602] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 01/12/2023]
Abstract
The highly polarized, typically very long, and nonmitotic nature of neurons present them with unique challenges in the maintenance of their homeostasis. This architectural complexity serves a rich and tightly controlled set of functions that enables their fast communication with neighboring cells and endows them with exquisite plasticity. The submembrane neuronal cytoskeleton occupies a pivotal position in orchestrating the structural patterning that determines local and long-range subcellular specialization, membrane dynamics, and a wide range of signaling events. At its center is the partnership between ankyrins and spectrins, which self-assemble with both remarkable long-range regularity and micro- and nanoscale specificity to precisely position and stabilize cell adhesion molecules, membrane transporters, ion channels, and other cytoskeletal proteins. To accomplish these generally conserved, but often functionally divergent and spatially diverse, roles these partners use a combinatorial program of a couple of dozens interacting family members, whose code is not fully unraveled. In a departure from their scaffolding roles, ankyrins and spectrins also enable the delivery of material to the plasma membrane by facilitating intracellular transport. Thus, it is unsurprising that deficits in ankyrins and spectrins underlie several neurodevelopmental, neurodegenerative, and psychiatric disorders. Here, I summarize key aspects of the biology of spectrins and ankyrins in the mammalian neuron and provide a snapshot of the latest advances in decoding their roles in the nervous system.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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29
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Häusler MG, Begemann M, Lidov HG, Kurth I, Darras BT, Elbracht M. A novel homozygous splice-site mutation in the SPTBN4 gene causes axonal neuropathy without intellectual disability. Eur J Med Genet 2019; 63:103826. [PMID: 31857255 DOI: 10.1016/j.ejmg.2019.103826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 11/14/2019] [Accepted: 12/14/2019] [Indexed: 10/25/2022]
Abstract
Mutations in spectrin beta non-erythrocytic 4 (SPTBN4) have been linked to congenital hypotonia, intellectual disability and motor neuropathy. Here we report on two siblings with a homozygous splice-site mutation in the SPTBN4 gene, lacking previously reported features of the disorder such as seizures, feeding difficulties, respiratory difficulties or profound intellectual disability. Our findings indicate that muscular hypotonia, myopathic facies with ptosis and axonal neuropathy can be the core clinical features in the SPTBN4 disorder and suggest that SPTBN4 mutation analysis should be considered in infants with marked axonal neuropathy.
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Affiliation(s)
- Martin G Häusler
- Division of Neuropediatrics and Social Pediatrics, Medical Faculty, RWTH Aachen University, Aachen, Germany.
| | - Matthias Begemann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Hart G Lidov
- Department of Pathology, Boston Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Miriam Elbracht
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
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30
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Lambert MW. The functional importance of lamins, actin, myosin, spectrin and the LINC complex in DNA repair. Exp Biol Med (Maywood) 2019; 244:1382-1406. [PMID: 31581813 DOI: 10.1177/1535370219876651] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Three major proteins in the nucleoskeleton, lamins, actin, and spectrin, play essential roles in maintenance of nuclear architecture and the integrity of the nuclear envelope, in mechanotransduction and mechanical coupling between the nucleoskeleton and cytoskeleton, and in nuclear functions such as regulation of gene expression, transcription and DNA replication. Less well known, but critically important, are the role these proteins play in DNA repair. The A-type and B-type lamins, nuclear actin and myosin, spectrin and the LINC (linker of nucleoskeleton and cytoskeleton) complex each function in repair of DNA damage utilizing various repair pathways. The lamins play a role in repair of DNA double-strand breaks (DSBs) by nonhomologous end joining (NHEJ) or homologous recombination (HR). Actin is involved in repair of DNA DSBs and interacts with myosin in facilitating relocalization of these DSBs in heterochromatin for HR repair. Nonerythroid alpha spectrin (αSpII) plays a critical role in repair of DNA interstrand cross-links (ICLs) where it acts as a scaffold in recruitment of repair proteins to sites of damage and is important in the initial damage recognition and incision steps of the repair process. The LINC complex contributes to the repair of DNA DSBs and ICLs. This review will address the important functions of these proteins in the DNA repair process, their mechanism of action, and the profound impact a defect or deficiency in these proteins has on cellular function. The critical roles of these proteins in DNA repair will be further emphasized by discussing the human disorders and the pathophysiological changes that result from or are related to deficiencies in these proteins. The demonstrated function for each of these proteins in the DNA repair process clearly indicates that there is another level of complexity that must be considered when mechanistically examining factors crucial for DNA repair.Impact statementProteins in the nucleoskeleton, lamins, actin, myosin, and spectrin, have been shown to play critical roles in DNA repair. Deficiencies in these proteins are associated with a number of disorders. This review highlights the role these proteins and their association with the LINC complex play in DNA repair processes, their mechanism of action and the impacts deficiencies in these proteins have on DNA repair and on disorders associated with a deficiency in these proteins. It will clarify how these proteins, which interact with “classic DNA repair proteins” (e.g., RAD51, XPF), represent another level of complexity in the DNA repair process, which must be taken into consideration when carrying out mechanistic studies on proteins involved in DNA repair and in developing models for DNA repair pathways. This knowledge is essential for determining how deficiencies in these proteins relate to disorders resulting from loss of functional activity of these proteins.
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Affiliation(s)
- Muriel W Lambert
- Department of Pathology, Immunology and Laboratory Medicine, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
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Leveille E, Estiar MA, Krohn L, Spiegelman D, Dionne-Laporte A, Dupré N, Trempe JF, Rouleau GA, Gan-Or Z. SPTAN1 variants as a potential cause for autosomal recessive hereditary spastic paraplegia. J Hum Genet 2019; 64:1145-1151. [DOI: 10.1038/s10038-019-0669-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/12/2019] [Accepted: 08/30/2019] [Indexed: 02/07/2023]
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Hamada N, Ogaya S, Nakashima M, Nishijo T, Sugawara Y, Iwamoto I, Ito H, Maki Y, Shirai K, Baba S, Maruyama K, Saitsu H, Kato M, Matsumoto N, Momiyama T, Nagata KI. De novo PHACTR1 mutations in West syndrome and their pathophysiological effects. Brain 2019; 141:3098-3114. [PMID: 30256902 DOI: 10.1093/brain/awy246] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
Trio-based whole exome sequencing identified two de novo heterozygous missense mutations [c.1449T > C/p.(Leu500Pro) and c.1436A > T/p.(Asn479Ile)] in PHACTR1, encoding a molecule critical for the regulation of protein phosphatase 1 (PP1) and the actin cytoskeleton, in unrelated Japanese individuals with West syndrome (infantile spasms with intellectual disability). We then examined the role of Phactr1 in the development of mouse cerebral cortex and the pathophysiological significance of these two mutations and others [c.1561C > T/p.(Arg521Cys) and c.1553T > A/p.(Ile518Asn)], which had been reported in undiagnosed patients with intellectual disability. Immunoprecipitation analyses revealed that actin-binding activity of PHACTR1 was impaired by the p.Leu500Pro, p.Asn479Ile and p.Ile518Asn mutations while the p.Arg521Cys mutation exhibited impaired binding to PP1. Acute knockdown of mouse Phactr1 using in utero electroporation caused defects in cortical neuron migration during corticogenesis, which were rescued by an RNAi-resistant PHACTR1 but not by the four mutants. Experiments using knockdown combined with expression mutants, aimed to mimic the effects of the heterozygous mutations under conditions of haploinsufficiency, suggested a dominant negative effect of the mutant allele. As for dendritic development in vivo, only the p.Arg521Cys mutant was determined to have dominant negative effects, because the three other mutants appeared to be degraded with these experimental conditions. Electrophysiological analyses revealed abnormal synaptic properties in Phactr1-deficient excitatory cortical neurons. Our data show that the PHACTR1 mutations may cause morphological and functional defects in cortical neurons during brain development, which is likely to be related to the pathophysiology of West syndrome and other neurodevelopmental disorders.
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Affiliation(s)
- Nanako Hamada
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan.,Research Fellow of Japan Society for the Promotion of Science, Japan
| | - Shunsuke Ogaya
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan
| | - Takuma Nishijo
- Department of Pharmacology, Jikei University School of Medicine, 3-19-18 Nishishimbashi, Minato-ku, Tokyo, Japan
| | - Yuji Sugawara
- Department of Pediatrics, Soka Municipal Hospital, 2-21-1 Soka, Soka, Saitama, Japan
| | - Ikuko Iwamoto
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Hidenori Ito
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Yuki Maki
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Kentaro Shirai
- Department of Pediatrics, Tsuchiura Kyodo Hospital, 4-1-1 Ootsuno, Tsuchiura, Ibaraki, Japan
| | - Shimpei Baba
- Department of Child Neurology, Comprehensive Epilepsy Center, Seirei-Hamamatsu General Hospital, 2-12-12 Sumiyoshi, Naka-ku, Hamamatsu, Shizuoka, Japan
| | - Koichi Maruyama
- Department of Pediatric Neurology, Central Hospital, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan
| | - Toshihiko Momiyama
- Department of Pharmacology, Jikei University School of Medicine, 3-19-18 Nishishimbashi, Minato-ku, Tokyo, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan.,Department of Neurochemistry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, Japan
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Machnicka B, Grochowalska R, Bogusławska DM, Sikorski AF. The role of spectrin in cell adhesion and cell-cell contact. Exp Biol Med (Maywood) 2019; 244:1303-1312. [PMID: 31226892 DOI: 10.1177/1535370219859003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Spectrins are proteins that are responsible for many aspects of cell function and adaptation to changing environments. Primarily the spectrin-based membrane skeleton maintains cell membrane integrity and its mechanical properties, together with the cytoskeletal network a support cell shape. The occurrence of a variety of spectrin isoforms in diverse cellular environments indicates that it is a multifunctional protein involved in numerous physiological pathways. Participation of spectrin in cell–cell and cell–extracellular matrix adhesion and formation of dynamic plasma membrane protrusions and associated signaling events is a subject of interest for researchers in the fields of cell biology and molecular medicine. In this mini-review, we focus on data concerning the role of spectrins in cell surface activities such as adhesion, cell–cell contact, and invadosome formation. We discuss data on different adhesion proteins that directly or indirectly interact with spectrin repeats. New findings support the involvement of spectrin in cell adhesion and spreading, formation of lamellipodia, and also the participation in morphogenetic processes, such as eye development, oogenesis, and angiogenesis. Here, we review the role of spectrin in cell adhesion and cell–cell contact.Impact statementThis article reviews properties of spectrins as a group of proteins involved in cell surface activities such as, adhesion and cell–cell contact, and their contribution to morphogenesis. We show a new area of research and discuss the involvement of spectrin in regulation of cell–cell contact leading to immunological synapse formation and in shaping synapse architecture during myoblast fusion. Data indicate involvement of spectrins in adhesion and cell–cell or cell–extracellular matrix interactions and therefore in signaling pathways. There is evidence of spectrin’s contribution to the processes of morphogenesis which are connected to its interactions with adhesion molecules, membrane proteins (and perhaps lipids), and actin. Our aim was to highlight the essential role of spectrin in cell–cell contact and cell adhesion.
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Affiliation(s)
- Beata Machnicka
- Department of Biochemistry and Bioinformatics, Faculty of Biological Sciences, University of Zielona Góra, Zielona Góra 65-516, Poland
| | - Renata Grochowalska
- Department of Biochemistry and Bioinformatics, Faculty of Biological Sciences, University of Zielona Góra, Zielona Góra 65-516, Poland
| | - Dżamila M Bogusławska
- Department of Biochemistry and Bioinformatics, Faculty of Biological Sciences, University of Zielona Góra, Zielona Góra 65-516, Poland
| | - Aleksander F Sikorski
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław 50-383, Poland
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Liu CH, Rasband MN. Axonal Spectrins: Nanoscale Organization, Functional Domains and Spectrinopathies. Front Cell Neurosci 2019; 13:234. [PMID: 31191255 PMCID: PMC6546920 DOI: 10.3389/fncel.2019.00234] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
Spectrin cytoskeletons are found in all metazoan cells, and their physical interactions between actin and ankyrins establish a meshwork that provides cellular structural integrity. With advanced super-resolution microscopy, the intricate spatial organization and associated functional properties of these cytoskeletons can now be analyzed with unprecedented clarity. Long neuronal processes like peripheral sensory and motor axons may be subject to intense mechanical forces including bending, stretching, and torsion. The spectrin-based cytoskeleton is essential to protect axons against these mechanical stresses. Additionally, spectrins are critical for the assembly and maintenance of axonal excitable domains including the axon initial segment and the nodes of Ranvier (NoR). These sites facilitate rapid and efficient action potential initiation and propagation in the nervous system. Recent studies revealed that pathogenic spectrin variants and diseases that protealyze and breakdown spectrins are associated with congenital neurological disorders and nervous system injury. Here, we review recent studies of spectrins in the nervous system and focus on their functions in axonal health and disease.
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Affiliation(s)
- Cheng-Hsin Liu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Matthew Neil Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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The Role of Nonerythroid Spectrin αII in Cancer. JOURNAL OF ONCOLOGY 2019; 2019:7079604. [PMID: 31186638 PMCID: PMC6521328 DOI: 10.1155/2019/7079604] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 12/18/2022]
Abstract
Nonerythroid spectrin αII (SPTAN1) is an important cytoskeletal protein that ensures vital cellular properties including polarity and cell stabilization. In addition, it is involved in cell adhesion, cell-cell contact, and apoptosis. The detection of altered expression of SPTAN1 in tumors indicates that SPTAN1 might be involved in the development and progression of cancer. SPTAN1 has been described in cancer and therapy response and proposed as a potential marker protein for neoplasia, tumor aggressiveness, and therapeutic efficiency. On one hand, the existing data suggest that overexpression of SPTAN1 in tumor cells reflects neoplastic and tumor promoting activity. On the other hand, nuclear SPTAN1 can have tumor suppressing effects by enabling DNA repair through interaction with DNA repair proteins. Moreover, SPTAN1 cleavage products occur during apoptosis and could serve as markers for the efficacy of cancer therapy. Due to SPTAN1's multifaceted functions and its role in adhesion and migration, SPTAN1 can influence tumor growth and progression in both positive and negative directions depending on its specific regulation. This review summarizes the current knowledge on SPTAN1 in cancer and depicts several mechanisms by which SPTAN1 could impact tumor development and aggressiveness.
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Møller RS, Hammer TB, Rubboli G, Lemke JR, Johannesen KM. From next-generation sequencing to targeted treatment of non-acquired epilepsies. Expert Rev Mol Diagn 2019; 19:217-228. [DOI: 10.1080/14737159.2019.1573144] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Rikke S. Møller
- Department of Epilepsy Genetics and Precision Medicine, The Danish Epilepsy Centre, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Trine B. Hammer
- Department of Epilepsy Genetics and Precision Medicine, The Danish Epilepsy Centre, Dianalund, Denmark
| | - Guido Rubboli
- Department of Epilepsy Genetics and Precision Medicine, The Danish Epilepsy Centre, Dianalund, Denmark
- Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Johannes R. Lemke
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Leipzig, Germany
| | - Katrine M. Johannesen
- Department of Epilepsy Genetics and Precision Medicine, The Danish Epilepsy Centre, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
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37
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Lambert MW. Spectrin and its interacting partners in nuclear structure and function. Exp Biol Med (Maywood) 2019; 243:507-524. [PMID: 29557213 DOI: 10.1177/1535370218763563] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nonerythroid αII-spectrin is a structural protein whose roles in the nucleus have just begun to be explored. αII-spectrin is an important component of the nucleoskelelton and has both structural and non-structural functions. Its best known role is in repair of DNA ICLs both in genomic and telomeric DNA. αII-spectrin aids in the recruitment of repair proteins to sites of damage and a proposed mechanism of action is presented. It interacts with a number of different groups of proteins in the nucleus, indicating it has roles in additional cellular functions. αII-spectrin, in its structural role, associates/co-purifies with proteins important in maintaining the architecture and mechanical properties of the nucleus such as lamin, emerin, actin, protein 4.1, nuclear myosin, and SUN proteins. It is important for the resilience and elasticity of the nucleus. Thus, αII-spectrin's role in cellular functions is complex due to its structural as well as non-structural roles and understanding the consequences of a loss or deficiency of αII-spectrin in the nucleus is a significant challenge. In the bone marrow failure disorder, Fanconi anemia, there is a deficiency in αII-spectrin and, among other characteristics, there is defective DNA repair, chromosome instability, and congenital abnormalities. One may speculate that a deficiency in αII-spectrin plays an important role not only in the DNA repair defect but also in the congenital anomalies observed in Fanconi anemia , particularly since αII-spectrin has been shown to be important in embryonic development in a mouse model. The dual roles of αII-spectrin in the nucleus in both structural and non-structural functions make this an extremely important protein which needs to be investigated further. Such investigations should help unravel the complexities of αII-spectrin's interactions with other nuclear proteins and enhance our understanding of the pathogenesis of disorders, such as Fanconi anemia , in which there is a deficiency in αII-spectrin. Impact statement The nucleoskeleton is critical for maintaining the architecture and functional integrity of the nucleus. Nonerythroid α-spectrin (αIISp) is an essential nucleoskeletal protein; however, its interactions with other structural and non-structural nuclear proteins and its functional importance in the nucleus have only begun to be explored. This review addresses these issues. It describes αIISp's association with DNA repair proteins and at least one proposed mechanism of action for its role in DNA repair. Specific interactions of αIISp with other nucleoskeletal proteins as well as its important role in the biomechanical properties of the nucleus are reviewed. The consequences of loss of αIISp, in disorders such as Fanconi anemia, are examined, providing insights into the profound impact of this loss on critical processes known to be abnormal in FA, such as development, carcinogenesis, cancer progression and cellular functions dependent upon αIISp's interactions with other nucleoskeletal proteins.
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Affiliation(s)
- Muriel W Lambert
- Department of Pathology and Laboratory Medicine, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ 07103, USA
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Gartner V, Markello TC, Macnamara E, De Biase A, Thurm A, Joseph L, Beggs A, Schmahmann JD, Berry GT, Anselm I, Boslet E, Tifft CJ, Gahl WA, Lee PR. Novel variants in SPTAN1 without epilepsy: An expansion of the phenotype. Am J Med Genet A 2018; 176:2768-2776. [PMID: 30548380 PMCID: PMC11157598 DOI: 10.1002/ajmg.a.40628] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/19/2018] [Accepted: 08/13/2018] [Indexed: 11/11/2022]
Abstract
We describe two unrelated children with de novo variants in the non-erythrocytic alpha-II-spectrin (SPTAN1) gene who have hypoplastic brain structures, intellectual disability, and both fine and gross motor impairments. Using agnostic exome sequencing, we identified a nonsense variant creating a premature stop codon in exon 21 of SPTAN1, and in a second patient we identified an intronic substitution in SPTAN1 prior to exon 50 creating a new donor acceptor site. Neither of these variants has been described previously. Although some of these patients' features are consistent with the known SPTAN1 encephalopathy phenotype, these two children do not have epilepsy, in contrast to reports about nearly every other patient with heterozygous SPTAN1 variants and in all patients with a variant near the C-terminal coding region. Moreover, both children have abnormal thyroid function, which has not been previously reported in association with SPTAN1 variant. We present a detailed discussion of the clinical manifestations of these two unique SPTAN1 variants and provide evidence that both variants result in reduced mRNA expression despite different locations within the gene and clinical phenotypes. These findings expand the motor, cognitive, and behavioral spectrum of the SPTAN1-associated phenotype and invite speculation about underlying pathophysiologies.
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Affiliation(s)
- Valerie Gartner
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | - Thomas C. Markello
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | - Ellen Macnamara
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | | | - Audrey Thurm
- Neurodevelopmental and Behavioral Phenotyping Service, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Lisa Joseph
- Neurodevelopmental and Behavioral Phenotyping Service, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Alan Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jeremy D. Schmahmann
- Ataxia Unit, Cognitive Behavioral Neurology Unit, Laboratory for Neuroanatomy and Cerebellar Neurobiology, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Gerard T. Berry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Irina Anselm
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Emma Boslet
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | - Cynthia J. Tifft
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | - William A. Gahl
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
| | - Paul R. Lee
- Office of the Clinical Director, NHGRI, and NIH Undiagnosed Diseases Program, Office of the Director, National Institutes of Health, Bethesda, Maryland
- Division of Neurology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland
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Bindu PS, Nagappa M, Chiplunkar S, Govindaraj P, Mathuranath PS, Sinha S, Taly AB. Clinical Reasoning: West syndrome, pontocerebellar hypoplasia, and hypomyelination in a 6-month-old boy. Neurology 2018; 91:e1652-e1656. [PMID: 30348860 DOI: 10.1212/wnl.0000000000006381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Parayil Sankaran Bindu
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India.
| | - Madhu Nagappa
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Shwetha Chiplunkar
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Periyasamy Govindaraj
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Pavagada S Mathuranath
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Sanjib Sinha
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Arun B Taly
- From the Department of Neurology (P.S.B., M.N., P.G., P.S.M., S.S., A.B.T.) and Neuromuscular Lab-Neurobiology Research Center (P.S.B., M.N., S.C., P.G., A.B.T.), National Institute of Mental Health and Neurosciences, Bangalore, India
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Mariano V, Domínguez-Iturza N, Neukomm LJ, Bagni C. Maintenance mechanisms of circuit-integrated axons. Curr Opin Neurobiol 2018; 53:162-173. [PMID: 30241058 DOI: 10.1016/j.conb.2018.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
Adult, circuit-integrated neurons must be maintained and supported for the life span of their host. The attenuation of either maintenance or plasticity leads to impaired circuit function and ultimately to neurodegenerative disorders. Over the last few years, significant discoveries of molecular mechanisms were made that mediate the formation and maintenance of axons. Here, we highlight intrinsic and extrinsic mechanisms that ensure the health and survival of axons. We also briefly discuss examples of mutations associated with impaired axonal maintenance identified in specific neurological conditions. A better understanding of these mechanisms will therefore help to define targets for therapeutic interventions.
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Affiliation(s)
- Vittoria Mariano
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Neurosciences KU Leuven, VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Nuria Domínguez-Iturza
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Neurosciences KU Leuven, VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Lukas J Neukomm
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland.
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy.
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Sriroopreddy R, Sajeed R, P R, C S. Differentially expressed gene (DEG) based protein-protein interaction (PPI) network identifies a spectrum of gene interactome, transcriptome and correlated miRNA in nondisjunction Down syndrome. Int J Biol Macromol 2018; 122:1080-1089. [PMID: 30218739 DOI: 10.1016/j.ijbiomac.2018.09.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
Abstract
Down syndrome, a genetic disorder of known attribution reveals several types of brain abnormalities resulting in mental retardation, inadequacy in speech and memory. In this study, we have presented a consolidative network approach to comprehend the intricacy of the associated genes of Down syndrome. In this analysis, the differentially expressed genes (DEG's) were identified and the central networks were constructed as upregulated and downregulated. Subsequently, GNB5, CDC42, SPTAN1, GNG2, GNAZ, PRKACB, SST, CD44, FGF2, PHLPP1, APP, and FYN were identified as the candidate hub genes by using topological parameters. Later, Fpclass a PPI tool identified WASP gene, a co-expression interacting partner with highest network topology. Moreover, an enhanced enrichment pathway namely Opioid signaling was obtained using ClueGo, depicting the roles of the hub genes in signaling and neuronal mechanisms. The transcriptional regulatory factors and the common miRNA connected to them were identified by using MatInspector and miRTarbase. Later, a regulatory network constructed showed that PLAG, T2FB, CREB, NEUR, and GATA were the most commonly connected transcriptional factors and hsa-miR-122-5p was the most prominent miRNA. In a nutshell, these hub genes and the enriched pathway could help understand at a molecular level and eventually used as therapeutic targets for Down syndrome.
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Affiliation(s)
- Ramireddy Sriroopreddy
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Rakshanda Sajeed
- Department of Analytics, School of Computer Science and Engineering, Vellore Institute of Technology, Vellore 632014, India
| | - Raghuraman P
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Sudandiradoss C
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology, Vellore 632014, India.
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42
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Jabbari K, Bobbili DR, Lal D, Reinthaler EM, Schubert J, Wolking S, Sinha V, Motameny S, Thiele H, Kawalia A, Altmüller J, Toliat MR, Kraaij R, van Rooij J, Uitterlinden AG, Ikram MA, Zara F, Lehesjoki AE, Krause R, Zimprich F, Sander T, Neubauer BA, May P, Lerche H, Nürnberg P. Rare gene deletions in genetic generalized and Rolandic epilepsies. PLoS One 2018; 13:e0202022. [PMID: 30148849 PMCID: PMC6110470 DOI: 10.1371/journal.pone.0202022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Genetic Generalized Epilepsy (GGE) and benign epilepsy with centro-temporal spikes or Rolandic Epilepsy (RE) are common forms of genetic epilepsies. Rare copy number variants have been recognized as important risk factors in brain disorders. We performed a systematic survey of rare deletions affecting protein-coding genes derived from exome data of patients with common forms of genetic epilepsies. We analysed exomes from 390 European patients (196 GGE and 194 RE) and 572 population controls to identify low-frequency genic deletions. We found that 75 (32 GGE and 43 RE) patients out of 390, i.e. ~19%, carried rare genic deletions. In particular, large deletions (>400 kb) represent a higher burden in both GGE and RE syndromes as compared to controls. The detected low-frequency deletions (1) share genes with brain-expressed exons that are under negative selection, (2) overlap with known autism and epilepsy-associated candidate genes, (3) are enriched for CNV intolerant genes recorded by the Exome Aggregation Consortium (ExAC) and (4) coincide with likely disruptive de novo mutations from the NPdenovo database. Employing several knowledge databases, we discuss the most prominent epilepsy candidate genes and their protein-protein networks for GGE and RE.
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Affiliation(s)
- Kamel Jabbari
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Cologne Biocenter, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Dheeraj R. Bobbili
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Eva M. Reinthaler
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Julian Schubert
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stefan Wolking
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Vishal Sinha
- Institute for Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - Susanne Motameny
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Amit Kawalia
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Institute of Human Genetics, University of Cologne, Cologne, Germany
| | | | - Robert Kraaij
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Jeroen van Rooij
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands
| | | | - M. Arfan Ikram
- Departments of Epidemiology, Neurology, and Radiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience, Institute G. Gaslini, Genova, Italy
| | - Anna-Elina Lehesjoki
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Neuroscience Center and Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Thomas Sander
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Bernd A. Neubauer
- Department of Neuropediatrics, Medical Faculty University Giessen, Giessen, Germany
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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43
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Rapaccini V, Esposito S, Strinati F, Allegretti M, Manfroi E, Miconi F, Pitzianti M, Prontera P, Principi N, Pasini A. A Child with a c.6923_6928dup (p.Arg2308_Met2309dup) SPTAN1 Mutation Associated with a Severe Early Infantile Epileptic Encephalopathy. Int J Mol Sci 2018; 19:ijms19071976. [PMID: 29986434 PMCID: PMC6073498 DOI: 10.3390/ijms19071976] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/02/2018] [Accepted: 07/03/2018] [Indexed: 12/25/2022] Open
Abstract
Early infantile epileptic encephalopathies (EIEEs) are a group of neurological disorders characterized by early-onset refractory seizures, severe electroencephalographic abnormalities, and developmental delay or intellectual disability. Recently, genetic studies have indicated that a significant portion of previously cryptogenic EIEEs are single-gene disorders. SPTAN1 is among the genes whose mutations are associated with EIEE development (OMIM# 613477). Here, a case of the c.6923_6928dup (p.Arg2308_Met2309dup) SPTAN1 mutation associated with a severe EIEE is reported. This case shows that mutations in the α20 repeat in the C-terminal of αII spectrin can be associated with EIEE. Duplication seems essential to cause EIEE. This causation is not demonstrated for amino acid deletions in the same spectrin residues. Reportedly, children with p.(Asp2303_Leu2305del) and p.(Gln2304_Gly2306del) deletions have childhood-onset epilepsy and no or marginal magnetic resonance imaging abnormalities, suggesting that not only the location but also the type of mutation plays a role in conditioning nervous system damage. Further studies are needed for a better understanding of the phenotype/genotype correlation in SPTAN1-related encephalopathies.
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Affiliation(s)
- Valentina Rapaccini
- Department of Systems Medicine, Unit of Child Neurology and Psychiatry, "Tor Vergata" University of Rome, 00133 Rome, Italy.
- Unità Sanitaria Locale (USL) Umbria 2, Viale VIII Marzo, 05100 Terni, Italy.
| | - Susanna Esposito
- Paediatric Clinic, Department of Surgical and Biomedical Sciences, Università degli Studi di Perugia, Piazza Menghini 1, 06132 Perugia, Italy.
| | - Francesco Strinati
- Unità Sanitaria Locale (USL) Umbria 2, Viale VIII Marzo, 05100 Terni, Italy.
| | | | | | - Francesco Miconi
- Paediatric Clinic, Department of Surgical and Biomedical Sciences, Università degli Studi di Perugia, Piazza Menghini 1, 06132 Perugia, Italy.
| | - Mariabernarda Pitzianti
- Department of Systems Medicine, Unit of Child Neurology and Psychiatry, "Tor Vergata" University of Rome, 00133 Rome, Italy.
- Unità Sanitaria Locale (USL) Umbria 2, Viale VIII Marzo, 05100 Terni, Italy.
| | - Paolo Prontera
- Medical Genetics Unit, S. Maria della Misericordia Hospital, 06132 Perugia, Italy.
| | | | - Augusto Pasini
- Department of Systems Medicine, Unit of Child Neurology and Psychiatry, "Tor Vergata" University of Rome, 00133 Rome, Italy.
- Unità Sanitaria Locale (USL) Umbria 2, Viale VIII Marzo, 05100 Terni, Italy.
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44
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Evaluating the pathogenic potential of genes with de novo variants in epileptic encephalopathies. Genet Med 2018; 21:17-27. [PMID: 29895856 PMCID: PMC6752304 DOI: 10.1038/s41436-018-0011-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/20/2018] [Indexed: 01/08/2023] Open
Abstract
Epileptic encephalopathies comprise a group of catastrophic epilepsies with heterogeneous genetic etiology. Although next-generation sequencing techniques can reveal a number of de novo variants in epileptic encephalopathies, evaluating the pathogenicity of these variants can be challenging. Determining the pathogenic potential of genes in epileptic encephalopathies is critical before evaluating the pathogenicity of variants identified in an individual. We reviewed de novo variants in epileptic encephalopathies, including their genotypes and functional consequences. We then evaluated the pathogenic potential of genes, with the following additional considerations: (1) recurrence of variants in unrelated cases, (2) information of previously defined phenotypes, and (3) data from genetic experimental studies. Genes related to epileptic encephalopathy revealed pathogenicity with distinct functional alterations, i.e., either a gain of function or loss of function in the majority; however, several genes warranted further study to confirm their pathogenic potential. Whether a gene was associated with distinct phenotype, the genotype (or functional alteration)-–phenotype correlation, and quantitative correlation between genetic impairment and phenotype severity were suggested to be specific evidence in determining the pathogenic role of genes. Data from epileptic encephalopathy-related genes would be helpful in outlining guidelines for evaluating the pathogenic potential of genes in other genetic disorders.
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45
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Wang CC, Ortiz-González XR, Yum SW, Gill SM, White A, Kelter E, Seaver LH, Lee S, Wiley G, Gaffney PM, Wierenga KJ, Rasband MN. βIV Spectrinopathies Cause Profound Intellectual Disability, Congenital Hypotonia, and Motor Axonal Neuropathy. Am J Hum Genet 2018; 102:1158-1168. [PMID: 29861105 PMCID: PMC5992132 DOI: 10.1016/j.ajhg.2018.04.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/24/2018] [Indexed: 12/31/2022] Open
Abstract
βIV spectrin links ankyrinG (AnkG) and clustered ion channels at axon initial segments (AISs) and nodes of Ranvier to the axonal cytoskeleton. Here, we report bi-allelic pathogenic SPTBN4 variants (three homozygous and two compound heterozygous) that cause a severe neurological syndrome that includes congenital hypotonia, intellectual disability, and motor axonal and auditory neuropathy. We introduced these variants into βIV spectrin, expressed these in neurons, and found that 5/7 were loss-of-function variants disrupting AIS localization or abolishing phosphoinositide binding. Nerve biopsies from an individual with a loss-of-function variant had reduced nodal Na+ channels and no nodal KCNQ2 K+ channels. Modeling the disease in mice revealed that although ankyrinR (AnkR) and βI spectrin can cluster Na+ channels and partially compensate for the loss of AnkG and βIV spectrin at nodes of Ranvier, AnkR and βI spectrin cannot cluster KCNQ2- and KCNQ3-subunit-containing K+ channels. Our findings define a class of spectrinopathies and reveal the molecular pathologies causing nervous-system dysfunction.
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Affiliation(s)
- Chih-Chuan Wang
- Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xilma R Ortiz-González
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sabrina W Yum
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sara M Gill
- Department of Audiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Amy White
- Department of Audiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Erin Kelter
- Women and Children's Hospital of Buffalo, Buffalo, NY 14203, USA
| | - Laurie H Seaver
- Spectrum Health Medical Genetics, MSU College of Human Medicine, Department of Pediatrics and Human Development, Grand Rapids, MI 49503, USA
| | - Sansan Lee
- Hawai'i Community Genetics, Honolulu, HI 96814, USA
| | - Graham Wiley
- Division of Genomics and Data Sciences, Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Patrick M Gaffney
- Division of Genomics and Data Sciences, Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Klaas J Wierenga
- Department of Pediatrics, Oklahoma University Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Matthew N Rasband
- Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA.
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46
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Huang CYM, Rasband MN. Axon initial segments: structure, function, and disease. Ann N Y Acad Sci 2018; 1420:46-61. [PMID: 29749636 DOI: 10.1111/nyas.13718] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/13/2018] [Accepted: 03/17/2018] [Indexed: 11/28/2022]
Abstract
The axon initial segment (AIS) is located at the proximal axon and is the site of action potential initiation. This reflects the high density of ion channels found at the AIS. Adaptive changes to the location and length of the AIS can fine-tune the excitability of neurons and modulate plasticity in response to activity. The AIS plays an important role in maintaining neuronal polarity by regulating the trafficking and distribution of proteins that function in somatodendritic or axonal compartments of the neuron. In this review, we provide an overview of the AIS cytoarchitecture, mechanism of assembly, and recent studies revealing mechanisms of differential transport at the AIS that maintain axon and dendrite identities. We further discuss how genetic mutations in AIS components (i.e., ankyrins, ion channels, and spectrins) and injuries may cause neurological disorders.
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Affiliation(s)
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas
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47
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Helbig I, Heinzen EL, Mefford HC. Genetic literacy series: Primer part 2-Paradigm shifts in epilepsy genetics. Epilepsia 2018; 59:1138-1147. [PMID: 29741288 DOI: 10.1111/epi.14193] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2018] [Indexed: 01/05/2023]
Abstract
This is the second of a 2-part primer on the genetics of the epilepsies within the Genetic Literacy Series of the Genetics Commission of the International League Against Epilepsy. In Part 1, we covered types of genetic variation, inheritance patterns, and their relationship to disease. In Part 2, we apply these basic principles to the case of a young boy with epileptic encephalopathy and ask 3 important questions: (1) Is the gene in question an established genetic etiology for epilepsy? (2) Is the variant in this particular gene pathogenic by established variant interpretation criteria? (3) Is the variant considered causative in the clinical context? These questions are considered and then answered for the clinical case in question.
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Affiliation(s)
- Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Erin L Heinzen
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
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48
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Abstract
Infantile spasms are a devastating epileptic encephalopathy characterized by early life spasms and later seizures. Clinical outcomes of infantile spasms are poor and therapeutic options are limited with significant adverse effects. Therefore, new strategies to treat infantile spasms are of the utmost importance. Animals models of infantile spasms are a critical component of developing new therapies. Here, we review current chronic animal models of infantile spasms and consider future advances that may help improve patient care, as well as our scientific understanding of this debilitating disease.
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49
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Akita T, Aoto K, Kato M, Shiina M, Mutoh H, Nakashima M, Kuki I, Okazaki S, Magara S, Shiihara T, Yokochi K, Aiba K, Tohyama J, Ohba C, Miyatake S, Miyake N, Ogata K, Fukuda A, Matsumoto N, Saitsu H. De novo variants in CAMK2A and CAMK2B cause neurodevelopmental disorders. Ann Clin Transl Neurol 2018; 5:280-296. [PMID: 29560374 PMCID: PMC5846454 DOI: 10.1002/acn3.528] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022] Open
Abstract
Objective α (CAMK2A) and β (CAMK2B) isoforms of Calcium/calmodulin‐dependent protein kinase II (CaMKII) play a pivotal role in neuronal plasticity and in learning and memory processes in the brain. Here, we explore the possible involvement of α‐ and β‐CaMKII variants in neurodevelopmental disorders. Methods Whole‐exome sequencing was performed for 976 individuals with intellectual disability, developmental delay, and epilepsy. The effect of CAMK2A and CAMK2B variants on CaMKII structure and firing of neurons was evaluated by computational structural analysis, immunoblotting, and electrophysiological analysis. Results We identified a total of five de novo CAMK2A and CAMK2B variants in three and two individuals, respectively. Seizures were common to three individuals with CAMK2A variants. Using a minigene splicing assay, we demonstrated that a splice site variant caused skipping of exon 11 leading to an in‐frame deletion of the regulatory segment of CaMKIIα. By structural analysis, four missense variants are predicted to impair the interaction between the kinase domain and the regulatory segment responsible for the autoinhibition of its kinase activity. The Thr286/Thr287 phosphorylation as a result of release from autoinhibition was increased in three mutants when the mutants were stably expressed in Neuro‐2a neuroblastoma cells. Expression of a CaMKIIα mutant in primary hippocampal neurons significantly increased A‐type K+ currents, which facilitated spike repolarization of single action potentials. Interpretation Our data highlight the importance of CaMKIIα and CaMKIIβ and their autoinhibitory regulation in human brain function, and suggest the enhancement of A‐type K+ currents as a possible pathophysiological basis.
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Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Kazushi Aoto
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuhiro Kato
- Department of Pediatrics Showa University School of Medicine 1-5-8 Hatanodai, Shinagawa-ku Tokyo 142-8666 Japan
| | - Masaaki Shiina
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hiroki Mutoh
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuko Nakashima
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan.,Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Ichiro Kuki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shin Okazaki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shinichi Magara
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Takashi Shiihara
- Department of Neurology Gunma Children's Medical Center 779 Shimohakoda, Hokkitsu-machi Shibukawa Gunma 377-8577 Japan
| | - Kenji Yokochi
- Department of Pediatric Neurology Seirei-Mikatahara General Hospital 3453 Mikatahara-cho, Kita-ku Hamamatsu 433-8558 Japan.,Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Kaori Aiba
- Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Jun Tohyama
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Chihiro Ohba
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Satoko Miyatake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Noriko Miyake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Kazuhiro Ogata
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Atsuo Fukuda
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Naomichi Matsumoto
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hirotomo Saitsu
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
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50
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Wang Y, Ji T, Nelson AD, Glanowska K, Murphy GG, Jenkins PM, Parent JM. Critical roles of αII spectrin in brain development and epileptic encephalopathy. J Clin Invest 2018; 128:760-773. [PMID: 29337302 DOI: 10.1172/jci95743] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/28/2017] [Indexed: 12/26/2022] Open
Abstract
The nonerythrocytic α-spectrin-1 (SPTAN1) gene encodes the cytoskeletal protein αII spectrin. Mutations in SPTAN1 cause early infantile epileptic encephalopathy type 5 (EIEE5); however, the role of αII spectrin in neurodevelopment and EIEE5 pathogenesis is unknown. Prior work suggests that αII spectrin is absent in the axon initial segment (AIS) and contributes to a diffusion barrier in the distal axon. Here, we have shown that αII spectrin is expressed ubiquitously in rodent and human somatodendritic and axonal domains. CRISPR-mediated deletion of Sptan1 in embryonic rat forebrain by in utero electroporation caused altered dendritic and axonal development, loss of the AIS, and decreased inhibitory innervation. Overexpression of human EIEE5 mutant SPTAN1 in embryonic rat forebrain and mouse hippocampal neurons led to similar developmental defects that were also observed in EIEE5 patient-derived neurons. Additionally, patient-derived neurons displayed aggregation of spectrin complexes. Taken together, these findings implicate αII spectrin in critical aspects of dendritic and axonal development and synaptogenesis, and support a dominant-negative mechanism of SPTAN1 mutations in EIEE5.
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Affiliation(s)
| | | | | | | | - Geoffrey G Murphy
- Molecular and Behavioral Neuroscience Institute.,Department of Molecular and Integrative Physiology, and
| | - Paul M Jenkins
- Department of Pharmacology.,Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, USA
| | - Jack M Parent
- Department of Neurology.,Ann Arbor VA Healthcare System, Ann Arbor, Michigan, USA
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