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Cuhadar U, Calzado-Reyes L, Pascual-Caro C, Aberra AS, Ritzau-Jost A, Aggarwal A, Ibata K, Podgorski K, Yuzaki M, Geis C, Hallerman S, Hoppa MB, de Juan-Sanz J. Activity-driven synaptic translocation of LGI1 controls excitatory neurotransmission. Cell Rep 2024; 43:114186. [PMID: 38700985 PMCID: PMC11156761 DOI: 10.1016/j.celrep.2024.114186] [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: 06/28/2022] [Revised: 12/14/2023] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
The fine control of synaptic function requires robust trans-synaptic molecular interactions. However, it remains poorly understood how trans-synaptic bridges change to reflect the functional states of the synapse. Here, we develop optical tools to visualize in firing synapses the molecular behavior of two trans-synaptic proteins, LGI1 and ADAM23, and find that neuronal activity acutely rearranges their abundance at the synaptic cleft. Surprisingly, synaptic LGI1 is primarily not secreted, as described elsewhere, but exo- and endocytosed through its interaction with ADAM23. Activity-driven translocation of LGI1 facilitates the formation of trans-synaptic connections proportionally to the history of activity of the synapse, adjusting excitatory transmission to synaptic firing rates. Accordingly, we find that patient-derived autoantibodies against LGI1 reduce its surface fraction and cause increased glutamate release. Our findings suggest that LGI1 abundance at the synaptic cleft can be acutely remodeled and serves as a critical control point for synaptic function.
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Affiliation(s)
- Ulku Cuhadar
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Lorenzo Calzado-Reyes
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Carlos Pascual-Caro
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Aman S Aberra
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Andreas Ritzau-Jost
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Abhi Aggarwal
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Keiji Ibata
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | | | - Michisuke Yuzaki
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | - Christian Geis
- Department of Neurology, Section Translational Neuroimmunology, Jena University Hospital, 07747 Jena, Germany
| | - Stefan Hallerman
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Michael B Hoppa
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Jaime de Juan-Sanz
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France.
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2
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Sachs S, Reinhard S, Eilts J, Sauer M, Werner C. Visualizing the trans-synaptic arrangement of synaptic proteins by expansion microscopy. Front Cell Neurosci 2024; 18:1328726. [PMID: 38486709 PMCID: PMC10937466 DOI: 10.3389/fncel.2024.1328726] [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: 10/27/2023] [Accepted: 02/13/2024] [Indexed: 03/17/2024] Open
Abstract
High fidelity synaptic neurotransmission in the millisecond range is provided by a defined structural arrangement of synaptic proteins. At the presynapse multi-epitope scaffolding proteins are organized spatially at release sites to guarantee optimal binding of neurotransmitters at receptor clusters. The organization of pre- and postsynaptic proteins in trans-synaptic nanocolumns would thus intuitively support efficient information transfer at the synapse. Visualization of these protein-dense regions as well as the minute size of protein-packed synaptic clefts remains, however, challenging. To enable efficient labeling of these protein complexes, we developed post-gelation immunolabeling expansion microscopy combined with Airyscan super-resolution microscopy. Using ~8-fold expanded samples, Airyscan enables multicolor fluorescence imaging with 20-40 nm spatial resolution. Post-immunolabeling of decrowded (expanded) samples provides increased labeling efficiency and allows the visualization of trans-synaptic nanocolumns. Our approach is ideally suited to investigate the pathological impact on nanocolumn arrangement e.g., in limbic encephalitis with autoantibodies targeting trans-synaptic leucine-rich glioma inactivated 1 protein (LGI1).
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Affiliation(s)
| | | | | | | | - Christian Werner
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
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3
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Wang S, Wang J, Li B, Hu N, Jin Y, Han S, Shang X. Case Report: Paroxysmal weakness of unilateral limb as an initial symptom in anti-LGI1 encephalitis: a report of five cases. Front Immunol 2023; 14:1191823. [PMID: 37304289 PMCID: PMC10248421 DOI: 10.3389/fimmu.2023.1191823] [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: 03/22/2023] [Accepted: 05/09/2023] [Indexed: 06/13/2023] Open
Abstract
Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is the second most common kind of autoimmune encephalitis following anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. Anti-LGI1 encephalitis is characterized by cognitive impairment or rapid progressive dementia, psychiatric disorders, epileptic seizures, faciobrachial dystonic seizures (FBDS), and refractory hyponatremia. Recently, we found an atypical manifestation of anti-LGI1 encephalitis, in which paroxysmal limb weakness was the initial symptom. In this report, we describe five cases of anti-LGI1 encephalitis with paroxysmal limb weakness. Patients had similar presentations, where a sudden weakness involving a unilateral limb was observed, which lasted several seconds and occurred dozens of times each day, with the anti-LGI1 antibody being positive in both serum and cerebrospinal fluid (CSF). FBDS occurred after a mean of 12 days following paroxysmal limb weakness in three of five patients (Cases 1, 4, and 5). All patients were given high-dose steroid therapy, which had a good effect on their condition. Based on this report, we suggest that paroxysmal unilateral weakness may be a kind of epilepsy and be connected to FBDS. As an unusual neurological presentation, paroxysmal weakness can be included in the clinical manifestations of anti-LGI1 encephalitis, helping to raise awareness of the recognition of anti-LGI1 encephalitis in patients with this symptom and leading to early diagnosis and early treatment, which would contribute to improved clinical outcomes.
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Sell J, Rahmati V, Kempfer M, Irani SR, Ritzau-Jost A, Hallermann S, Geis C. Comparative Effects of Domain-Specific Human Monoclonal Antibodies Against LGI1 on Neuronal Excitability. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2023; 10:e200096. [PMID: 37028941 PMCID: PMC10099296 DOI: 10.1212/nxi.0000000000200096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 01/04/2023] [Indexed: 04/09/2023]
Abstract
BACKGROUND AND OBJECTIVES Autoantibodies to leucine-rich glioma inactivated protein 1 (LGI1) cause an autoimmune limbic encephalitis with frequent focal seizures and anterograde memory dysfunction. LGI1 is a neuronal secreted linker protein with 2 functional domains: the leucine-rich repeat (LRR) and epitempin (EPTP) regions. LGI1 autoantibodies are known to interfere with presynaptic function and neuronal excitability; however, their epitope-specific mechanisms are incompletely understood. METHODS We used patient-derived monoclonal autoantibodies (mAbs), which target either LRR or EPTP domains of LGI1 to investigate long-term antibody-induced alteration of neuronal function. LRR- and EPTP-specific effects were evaluated by patch-clamp recordings in cultured hippocampal neurons and compared with biophysical neuron modeling. Kv1.1 channel clustering at the axon initial segment (AIS) was quantified by immunocytochemistry and structured illumination microscopy techniques. RESULTS Both EPTP and LRR domain-specific mAbs decreased the latency of first somatic action potential firing. However, only the LRR-specific mAbs increased the number of action potential firing together with enhanced initial instantaneous frequency and promoted spike-frequency adaptation, which were less pronounced after the EPTP mAb. This also led to an effective reduction in the slope of ramp-like depolarization in the subthreshold response, suggesting Kv1 channel dysfunction. A biophysical model of a hippocampal neuron corroborated experimental results and suggests that an isolated reduction of the conductance of Kv1-mediated K+ currents largely accounts for the antibody-induced alterations in the initial firing phase and spike-frequency adaptation. Furthermore, Kv1.1 channel density was spatially redistributed from the distal toward the proximal site of AIS under LRR mAb treatment and, to a lesser extant, under EPTP mAb. DISCUSSION These findings indicate an epitope-specific pathophysiology of LGI1 autoantibodies. The pronounced neuronal hyperexcitability and SFA together with dropped slope of ramp-like depolarization after LRR-targeted interference suggest disruption of LGI1-dependent clustering of K+ channel complexes. Moreover, considering the effective triggering of action potentials at the distal AIS, the altered spatial distribution of Kv1.1 channel density may contribute to these effects through impairing neuronal control of action potential initiation and synaptic integration.
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Affiliation(s)
- Josefine Sell
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Vahid Rahmati
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Marin Kempfer
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Sarosh R Irani
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Andreas Ritzau-Jost
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Stefan Hallermann
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany
| | - Christian Geis
- From the Section Translational Neuroimmunology (J.S., V.R., M.K., C.G.), Department of Neurology, Jena University Hospital, Germany; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, UK; Department of Neurology (S.R.I.), Oxford University Hospitals, UK; and Carl-Ludwig-Institute of Physiology (A.R.-J., S.H.), Faculty of Medicine, Leipzig University, Germany.
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5
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Zhou L, Wang K, Xu Y, Dong BB, Wu DC, Wang ZX, Wang XT, Cai XY, Yang JT, Zheng R, Chen W, Shen Y, Wei JS. A patient-derived mutation of epilepsy-linked LGI1 increases seizure susceptibility through regulating K v1.1. Cell Biosci 2023; 13:34. [PMID: 36804022 PMCID: PMC9940402 DOI: 10.1186/s13578-023-00983-y] [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: 12/30/2022] [Accepted: 02/04/2023] [Indexed: 02/22/2023] Open
Abstract
BACKGROUND Autosomal dominant lateral temporal epilepsy (ADLTE) is an inherited syndrome caused by mutations in the leucine-rich glioma inactivated 1 (LGI1) gene. It is known that functional LGI1 is secreted by excitatory neurons, GABAergic interneurons, and astrocytes, and regulates AMPA-type glutamate receptor-mediated synaptic transmission by binding ADAM22 and ADAM23. However, > 40 LGI1 mutations have been reported in familial ADLTE patients, more than half of which are secretion-defective. How these secretion-defective LGI1 mutations lead to epilepsy is unknown. RESULTS We identified a novel secretion-defective LGI1 mutation from a Chinese ADLTE family, LGI1-W183R. We specifically expressed mutant LGI1W183R in excitatory neurons lacking natural LGI1, and found that this mutation downregulated Kv1.1 activity, led to neuronal hyperexcitability and irregular spiking, and increased epilepsy susceptibility in mice. Further analysis revealed that restoring Kv1.1 in excitatory neurons rescued the defect of spiking capacity, improved epilepsy susceptibility, and prolonged the life-span of mice. CONCLUSIONS These results describe a role of secretion-defective LGI1 in maintaining neuronal excitability and reveal a new mechanism in the pathology of LGI1 mutation-related epilepsy.
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Affiliation(s)
- Lin Zhou
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Kang Wang
- grid.452661.20000 0004 1803 6319Department of Neurology, First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310003 China
| | - Yuxiang Xu
- grid.256922.80000 0000 9139 560XSchool of Life Sciences, Henan University, Kaifeng, 475004 China
| | - Bin-Bin Dong
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Deng-Chang Wu
- grid.452661.20000 0004 1803 6319Department of Neurology, First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310003 China
| | - Zhao-Xiang Wang
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Xin-Tai Wang
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Xin-Yu Cai
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Jin-Tao Yang
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Rui Zheng
- grid.13402.340000 0004 1759 700XDepartment of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020 China
| | - Wei Chen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020, China.
| | - Ying Shen
- Department of Physiology and Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310020, China.
| | - Jian-She Wei
- School of Life Sciences, Henan University, Kaifeng, 475004, China.
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6
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Liu J, Hu D, Zhang Z, Tang F, Yan Y, Ma Y. Autosomal dominant lateral temporal epilepsy in a family exhibiting a rare heterozygous mutation and deletion in the leucine-rich glioma inactivated 1 gene. Neurosci Lett 2022; 782:136698. [PMID: 35643238 DOI: 10.1016/j.neulet.2022.136698] [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: 02/13/2022] [Revised: 05/08/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022]
Abstract
Autosomal dominant lateral temporal epilepsy (ADLTE) is an inherited syndrome caused by mutations in the leucine-rich glioma inactivated 1 (LGI1) gene. In a family with six ADLTE patients spanning four generations, our linkage and exome sequencing investigations revealed a rare frameshift heterozygous mutation in LGI1 (c.1494del(p.Phe498LeufsTer15)). Gene cloning methods were used to create plasmids with wild-type and mutant LGI1 alleles. Through transfection of HEK293 cells and primary neurons, they were utilized to assess the subcellular location of wild-type and mutant LGI1. Moreover, the plasmid-transfected primary neurons were analyzed for neuronal complexity and density of dendritic spines. According to our results. the mutation decreased LGI1 secretion in transfected HEK293 cells. In primary neurons, mutant LGI1 affected neuronal polarity and complexity. Our findings have broadened the phenotypic spectrum of LGI1 mutations and provided evidence regarding the pathogenicity of this mutation. In addition, we discovered new information about the role of LGI1 in the development of temporal lobe epilepsy, along with a possible link between neuronal polarity disorder and ADLTE.
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Affiliation(s)
- Jie Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Danmei Hu
- Department of Neurology, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Taiyuan 030032, China
| | - Zhijuan Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Fenglin Tang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Yin Yan
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Yuanlin Ma
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China.
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7
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Baudin P, Cousyn L, Navarro V. The LGI1 protein: molecular structure, physiological functions and disruption-related seizures. Cell Mol Life Sci 2021; 79:16. [PMID: 34967933 PMCID: PMC11072701 DOI: 10.1007/s00018-021-04088-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 01/16/2023]
Abstract
Leucine-rich, glioma inactivated 1 (LGI1) is a secreted glycoprotein, mainly expressed in the brain, and involved in central nervous system development and physiology. Mutations of LGI1 have been linked to autosomal dominant lateral temporal lobe epilepsy (ADLTE). Recently auto-antibodies against LGI1 have been described as the basis for an autoimmune encephalitis, associated with specific motor and limbic epileptic seizures. It is the second most common cause of autoimmune encephalitis. This review presents details on the molecular structure, expression and physiological functions of LGI1, and examines how their disruption underlies human pathologies. Knock-down of LGI1 in rodents reveals that this protein is necessary for normal brain development. In mature brains, LGI1 is associated with Kv1 channels and AMPA receptors, via domain-specific interaction with membrane anchoring proteins and contributes to regulation of the expression and function of these channels. Loss of function, due to mutations or autoantibodies, of this key protein in the control of neuronal activity is a common feature in the genesis of epileptic seizures in ADLTE and anti-LGI1 autoimmune encephalitis.
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Affiliation(s)
- Paul Baudin
- Sorbonne Université, Paris Brain Institute - Institut du Cerveau, ICM, INSERM, CNRS, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Louis Cousyn
- Sorbonne Université, Paris Brain Institute - Institut du Cerveau, ICM, INSERM, CNRS, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
- AP-HP, Epilepsy Unit, Pitié-Salpêtrière Hospital, DMU Neurosciences, Paris, France
| | - Vincent Navarro
- Sorbonne Université, Paris Brain Institute - Institut du Cerveau, ICM, INSERM, CNRS, AP-HP, Pitié-Salpêtrière Hospital, Paris, France.
- AP-HP, Epilepsy Unit, Pitié-Salpêtrière Hospital, DMU Neurosciences, Paris, France.
- AP-HP, Center of Reference for Rare Epilepsies, Pitié-Salpêtrière Hospital, 47-83 Boulevard de l'Hôpital, 75013, Paris, France.
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8
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Hu P, Wu D, Zang YY, Wang Y, Zhou YP, Qiao F, Teng XY, Chen J, Li QQ, Sun JH, Liu T, Feng HY, Zhou QG, Shi YS, Xu Z. A novel LGI1 mutation causing autosomal dominant lateral temporal lobe epilepsy confirmed by a precise knock-in mouse model. CNS Neurosci Ther 2021; 28:237-246. [PMID: 34767694 PMCID: PMC8739050 DOI: 10.1111/cns.13761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 12/30/2022] Open
Abstract
AIMS This study aimed to explore the pathomechanism of a mutation on the leucine-rich glioma inactivated 1 gene (LGI1) identified in a family having autosomal dominant lateral temporal lobe epilepsy (ADLTE), using a precise knock-in mouse model. METHODS AND RESULTS A novel LGI1 mutation, c.152A>G; p. Asp51Gly, was identified by whole exome sequencing in a Chinese family with ADLTE. The pathomechanism of the mutation was explored by generating Lgi1D51G knock-in mice that precisely phenocopied the epileptic symptoms of human patients. The Lgi1D51G / D51G mice showed spontaneous recurrent generalized seizures and premature death. The Lgi1D51G /+ mice had partial epilepsy, with half of them displaying epileptiform discharges on electroencephalography. They also showed enhanced sensitivity to the convulsant agent pentylenetetrazole. Mechanistically, the secretion of Lgi1 was impaired in the brain of the D51G knock-in mice and the protein level was drastically reduced. Moreover, the antiepileptic drugs, carbamazepine, oxcarbazepine, and sodium valproate, could prolong the survival time of Lgi1D51G / D51G mice, and oxcarbazepine appeared to be the most effective. CONCLUSIONS We identified a novel epilepsy-causing mutation of LGI1 in humans. The Lgi1D51G /+ mouse model, precisely phenocopying epileptic symptoms of human patients, could be a useful tool in future studies on the pathogenesis and potential therapies for epilepsy.
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Affiliation(s)
- Ping Hu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health care Hospital, Nanjing, China
| | - Dan Wu
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Yan-Yu Zang
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Yan Wang
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health care Hospital, Nanjing, China
| | - Ya-Ping Zhou
- School of Pharmacy, Nanjing Medical University, Nanjing, China
| | - Fengchang Qiao
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health care Hospital, Nanjing, China
| | - Xiao-Yu Teng
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Jiang Chen
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Qing-Qing Li
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Jia-Hui Sun
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - TingTing Liu
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Hao-Yang Feng
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health care Hospital, Nanjing, China
| | - Qi-Gang Zhou
- School of Pharmacy, Nanjing Medical University, Nanjing, China
| | - Yun Stone Shi
- Minister of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Department of Neurology, Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, National Resource for Mutant Mice, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China.,Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing, China.,Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Zhengfeng Xu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health care Hospital, Nanjing, China
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9
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Fels E, Muñiz-Castrillo S, Vogrig A, Joubert B, Honnorat J, Pascual O. Role of LGI1 protein in synaptic transmission: From physiology to pathology. Neurobiol Dis 2021; 160:105537. [PMID: 34695575 DOI: 10.1016/j.nbd.2021.105537] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 01/17/2023] Open
Abstract
Leucine-Rich Glioma Inactivated protein 1 (LGI1) is a secreted neuronal protein highly expressed in the central nervous system and high amount are found in the hippocampus. An alteration of its function has been described in few families of patients with autosomal dominant temporal lobe epilepsy (ADLTE) or with autoimmune limbic encephalitis (LE), both characterized by epileptic seizures. Studies have shown that LGI1 plays an essential role during development, but also in neuronal excitability through an action on voltage-gated potassium Kv1.1 channels, and in synaptic transmission by regulating the surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPA-R). Over the last decade, a growing number of studies investigating LGI1 functions have been published. They aimed to improve the understanding of LGI1 function in the regulation of neuronal networks using different animal and cellular models. LGI1 appears to be a major actor of synaptic regulation by modulating trans-synaptically pre- and post-synaptic proteins. In this review, we will focus on LGI1 binding partners, "A Disintegrin And Metalloprotease (ADAM) 22 and 23", the complex they form at the synapse, and will discuss the effects of LGI1 on neuronal excitability and synaptic transmission in physiological and pathological conditions. Finally, we will highlight new insights regarding N-terminal Leucine-Rich Repeat (LRR) domain and C-terminal Epitempin repeat (EPTP) domain and their potentially distinct role in LGI1 function.
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Affiliation(s)
- Elodie Fels
- Synaptopathies and Auto-antibodies (SynatAc) Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Universités de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France
| | - Sergio Muñiz-Castrillo
- Synaptopathies and Auto-antibodies (SynatAc) Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Universités de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France; French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Alberto Vogrig
- Synaptopathies and Auto-antibodies (SynatAc) Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Universités de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France; French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Bastien Joubert
- Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France; French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Jérôme Honnorat
- Synaptopathies and Auto-antibodies (SynatAc) Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Universités de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France; French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677 Bron Cedex, France.
| | - Olivier Pascual
- Synaptopathies and Auto-antibodies (SynatAc) Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Universités de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Université Claude Bernard Lyon 1, Universités de Lyon, Lyon, France.
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10
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Matsushima N, Takatsuka S, Miyashita H, Kretsinger RH. Leucine Rich Repeat Proteins: Sequences, Mutations, Structures and Diseases. Protein Pept Lett 2019; 26:108-131. [PMID: 30526451 DOI: 10.2174/0929866526666181208170027] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022]
Abstract
Mutations in the genes encoding Leucine Rich Repeat (LRR) containing proteins are associated with over sixty human diseases; these include high myopia, mitochondrial encephalomyopathy, and Crohn's disease. These mutations occur frequently within the LRR domains and within the regions that shield the hydrophobic core of the LRR domain. The amino acid sequences of fifty-five LRR proteins have been published. They include Nod-Like Receptors (NLRs) such as NLRP1, NLRP3, NLRP14, and Nod-2, Small Leucine Rich Repeat Proteoglycans (SLRPs) such as keratocan, lumican, fibromodulin, PRELP, biglycan, and nyctalopin, and F-box/LRR-repeat proteins such as FBXL2, FBXL4, and FBXL12. For example, 363 missense mutations have been identified. Replacement of arginine, proline, or cysteine by another amino acid, or the reverse, is frequently observed. The diverse effects of the mutations are discussed based on the known structures of LRR proteins. These mutations influence protein folding, aggregation, oligomerization, stability, protein-ligand interactions, disulfide bond formation, and glycosylation. Most of the mutations cause loss of function and a few, gain of function.
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Affiliation(s)
- Norio Matsushima
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan.,Institute of Tandem Repeats, Noboribetsu 059-0464, Japan
| | - Shintaro Takatsuka
- Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroki Miyashita
- Institute of Tandem Repeats, Noboribetsu 059-0464, Japan.,Hokubu Rinsho Co., Ltd, Sapporo 060-0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, United States
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11
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Lefevre E, Gooch H, Josh P, Alexander S, Eyles DW, Burne TH. Functional and molecular changes in the nucleus accumbens of MK-801-sensitized rats. Behav Pharmacol 2019; 30:383-395. [DOI: 10.1097/fbp.0000000000000447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Liu F, Du C, Tian X, Ma Y, Zhao B, Yan Y, Lin Z, Lin P, Zhou R, Wang X. A novel LGI1 missense mutation causes dysfunction in cortical neuronal migration and seizures. Brain Res 2019; 1721:146332. [PMID: 31301272 DOI: 10.1016/j.brainres.2019.146332] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/23/2019] [Accepted: 07/09/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND To explore the causative genes and pathogenesis of autosomal dominant partial epilepsy with auditory features in a large Chinese family that includes 7 patients over four generations. METHODS We used targeted exome sequencing and Sanger sequencing to validate the mutation. Zebrafish were used to explore the epileptic behavior caused by the mutation. Primary cortical neuronal culturing and in utero electroporation were used to observe the influences of the mutation on neuronal polarity and migration. RESULTS We report the identification of a novel missense mutation, c.128C > G (p. Pro43Arg), in exon 1 of LGI1. The heterozygous missense mutation, which cosegregated with the syndrome, was absent in 300 unrelated and matched-ancestor controls. The mutation inhibited the secretion of LGI1 and could not rescue the hyperactivity caused by lgi1a knockdown in zebrafish. In vitro, mutant LGI1 interrupts normal cell polarity. In agreement with these findings, dysfunctional cortical neuron migration was observed using in utero electroporation technology, which is reminiscent of the subtle structural changes in the lateral temporal region observed in the proband of this family. CONCLUSION Our findings enrich the spectrum of LGI1 mutations and support the pathogenicity of the mutation. Furthermore, additional information regarding the role of LGI1 in the development of temporal lobe epilepsy was elucidated, and a potential relationship was established between cortical neuronal migration dysfunction and autosomal dominant partial epilepsy with auditory features.
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Affiliation(s)
- Feng Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Chao Du
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Xin Tian
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Yuanlin Ma
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Bei Zhao
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Yin Yan
- Department of Neurology, The Ninth People's Hospital of Chongqing, Chongqing 400016, China
| | - Zijun Lin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Peijia Lin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Ruijiao Zhou
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing 400016, China.
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13
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Inactivation of Lgi1 in murine neuronal precursor cells leads to dysregulation of axon guidance pathways. Genomics 2019; 112:1167-1172. [PMID: 31276752 DOI: 10.1016/j.ygeno.2019.07.001] [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: 01/09/2019] [Revised: 05/22/2019] [Accepted: 07/01/2019] [Indexed: 11/20/2022]
Abstract
LGI1 mutations predispose to a rare epilepsy syndrome and when inactivated in mice leads to early onset seizures and premature death. Histopathology of the mature brain soon after birth shows cortical dysplasia in Lgi1 null mice with hypercellularity in the outer cortical layers. Here we show extensive gene expression changes in neuronal precursor cells from Lgi1 null mice compared with wild type mice. The most significantly dysregulated pathway involves canonical axon guidance signaling with multiple networks involved in cell movement, adhesion and invasion related to actin cytoskeleton reorganization. The Lgi1 null NPCs show increased cell motility in vitro compared with normal counterparts. Dysregulation of genes critical to cell movement/migration and critical transcription factors involved in early neuronal development is a prominent feature. These studies provide a critical mechanistic link to the observation of increased cellularity in the outer layers of the developing cortex in Lgi1 null mice.
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14
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Geis C, Planagumà J, Carreño M, Graus F, Dalmau J. Autoimmune seizures and epilepsy. J Clin Invest 2019; 129:926-940. [PMID: 30714986 DOI: 10.1172/jci125178] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The rapid expansion in the number of encephalitis disorders associated with autoantibodies against neuronal proteins has led to an incremental increase in use of the term "autoimmune epilepsy," yet has occurred with limited attention to the physiopathology of each disease and genuine propensity to develop epilepsy. Indeed, most autoimmune encephalitides present with seizures, but the probability of evolving to epilepsy is relatively small. The risk of epilepsy is higher for disorders in which the antigens are intracellular (often T cell-mediated) compared with disorders in which the antigens are on the cell surface (antibody-mediated). Most autoantibodies against neuronal surface antigens show robust effects on the target proteins, resulting in hyperexcitability and impairment of synaptic function and plasticity. Here, we trace the evolution of the concept of autoimmune epilepsy and examine common inflammatory pathways that might lead to epilepsy. Then, we focus on several antibody-mediated encephalitis disorders that associate with seizures and review the synaptic alterations caused by patients' antibodies, with emphasis on those that have been modeled in animals (e.g., antibodies against NMDA, AMPA receptors, LGI1 protein) or in cultured neurons (e.g., antibodies against the GABAb receptor).
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Affiliation(s)
- Christian Geis
- Department of Neurology, Jena University Hospital, Jena, Germany
| | - Jesus Planagumà
- Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and
| | - Mar Carreño
- Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Francesc Graus
- Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and.,Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Josep Dalmau
- Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and.,Hospital Clinic, University of Barcelona, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain.,Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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15
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Petit-Pedrol M, Sell J, Planagumà J, Mannara F, Radosevic M, Haselmann H, Ceanga M, Sabater L, Spatola M, Soto D, Gasull X, Dalmau J, Geis C. LGI1 antibodies alter Kv1.1 and AMPA receptors changing synaptic excitability, plasticity and memory. Brain 2018; 141:3144-3159. [PMID: 30346486 PMCID: PMC6202570 DOI: 10.1093/brain/awy253] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 08/23/2018] [Accepted: 08/28/2018] [Indexed: 12/23/2022] Open
Abstract
Leucine-rich glioma-inactivated 1 (LGI1) is a secreted neuronal protein that forms a trans-synaptic complex that includes the presynaptic disintegrin and metalloproteinase domain-containing protein 23 (ADAM23), which interacts with voltage-gated potassium channels Kv1.1, and the postsynaptic ADAM22, which interacts with AMPA receptors. Human autoantibodies against LGI1 associate with a form of autoimmune limbic encephalitis characterized by severe but treatable memory impairment and frequent faciobrachial dystonic seizures. Although there is evidence that this disease is immune-mediated, the underlying LGI1 antibody-mediated mechanisms are unknown. Here, we used patient-derived immunoglobulin G (IgG) antibodies to determine the main epitope regions of LGI1 and whether the antibodies disrupt the interaction of LGI1 with ADAM23 and ADAM22. In addition, we assessed the effects of patient-derived antibodies on Kv1.1, AMPA receptors, and memory in a mouse model based on cerebroventricular transfer of patient-derived IgG. We found that IgG from all patients (n = 25), but not from healthy participants (n = 20), prevented the binding of LGI1 to ADAM23 and ADAM22. Using full-length LGI1, LGI3, and LGI1 constructs containing the LRR1 domain (EPTP1-deleted) or EPTP1 domain (LRR3-EPTP1), IgG from all patients reacted with epitope regions contained in the LRR1 and EPTP1 domains. Confocal analysis of hippocampal slices of mice infused with pooled IgG from eight patients, but not pooled IgG from controls, showed a decrease of total and synaptic levels of Kv1.1 and AMPA receptors. The effects on Kv1.1 preceded those involving the AMPA receptors. In acute slice preparations of hippocampus, patch-clamp analysis from dentate gyrus granule cells and CA1 pyramidal neurons showed neuronal hyperexcitability with increased glutamatergic transmission, higher presynaptic release probability, and reduced synaptic failure rate upon minimal stimulation, all likely caused by the decreased expression of Kv1.1. Analysis of synaptic plasticity by recording field potentials in the CA1 region of the hippocampus showed a severe impairment of long-term potentiation. This defect in synaptic plasticity was independent from Kv1 blockade and was possibly mediated by ineffective recruitment of postsynaptic AMPA receptors. In parallel with these findings, mice infused with patient-derived IgG showed severe memory deficits in the novel object recognition test that progressively improved after stopping the infusion of patient-derived IgG. Different from genetic models of LGI1 deficiency, we did not observe aberrant dendritic sprouting or defective synaptic pruning as potential cause of the symptoms. Overall, these findings demonstrate that patient-derived IgG disrupt presynaptic and postsynaptic LGI1 signalling, causing neuronal hyperexcitability, decreased plasticity, and reversible memory deficits.
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Affiliation(s)
- Mar Petit-Pedrol
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Josefine Sell
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Jesús Planagumà
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Francesco Mannara
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Marija Radosevic
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Holger Haselmann
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Mihai Ceanga
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Lidia Sabater
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Marianna Spatola
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- University of Lausanne (UNIL), Lausanne, Switzerland
| | - David Soto
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- Laboratori de Neurofisiologia, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Josep Dalmau
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- Department of Neurology, University of Pennsylvania, Philadelphia, USA
- Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Valencia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Christian Geis
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
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16
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Xie YJ, Zhou L, Wang Y, Jiang NW, Cao S, Shao CY, Wang XT, Li XY, Shen Y, Zhou L. Leucine-Rich Glioma Inactivated 1 Promotes Oligodendrocyte Differentiation and Myelination via TSC-mTOR Signaling. Front Mol Neurosci 2018; 11:231. [PMID: 30034322 PMCID: PMC6043672 DOI: 10.3389/fnmol.2018.00231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
Leucine-rich glioma inactivated 1 (Lgi1), a putative tumor suppressor, is tightly associated with autosomal dominant lateral temporal lobe epilepsy (ADLTE). It has been shown that Lgi1 regulates the myelination of Schwann cells in the peripheral nervous system (PNS). However, the function and underlying mechanisms for Lgi1 regulation of oligodendrocyte differentiation and myelination in the central nervous system (CNS) remain elusive. In addition, whether Lgi1 is required for myelin maintenance is unknown. Here, we show that Lgi1 is necessary and sufficient for the differentiation of oligodendrocyte precursor cells and is also required for the maintenance of myelinated fibers. The hypomyelination in Lgi1-/- mice attributes to the inhibition of the biosynthesis of lipids and proteins in oligodendrocytes (OLs). Moreover, we found that Lgi1 deficiency leads to a decrease in expression of tuberous sclerosis complex 1 (TSC1) and activates mammalian target of rapamycin signaling. Together, the present work establishes that Lgi1 is a regulator of oligodendrocyte development and myelination in CNS.
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Affiliation(s)
- Ya-Jun Xie
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Lin Zhou
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Yin Wang
- Laboratory of Craniocerebral Diseases of Ningxia Hui Autonomous Region, Ningxia Medical UniversityYinchuan, China
| | - Nan-Wei Jiang
- Ningbo Key Laboratory of Behavioral Neuroscience, Department of Physiology and Pharmacology, Ningbo University School of MedicineNingbo, China
| | - Shenglong Cao
- Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou, China
| | - Chong-Yu Shao
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Xin-Tai Wang
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Xiang-Yao Li
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Ying Shen
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
| | - Liang Zhou
- Key Laboratory of Medical Neurobiology of Ministry of Health, Department of Neurobiology, Zhejiang University School of MedicineHangzhou, China
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17
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Gadoth A, Pittock SJ, Dubey D, McKeon A, Britton JW, Schmeling JE, Smith A, Kotsenas AL, Watson RE, Lachance DH, Flanagan EP, Lennon VA, Klein CJ. Expanded phenotypes and outcomes among 256 LGI1/CASPR2-IgG-positive patients. Ann Neurol 2017. [PMID: 28628235 DOI: 10.1002/ana.24979] [Citation(s) in RCA: 208] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To describe an expanded phenotypic spectrum and longitudinal outcome in 256 LGI1-IgG-seropositive and/or CASPR2-IgG-seropositive patients. METHODS Patients were identified through service neural autoantibody evaluation. Ninety-five had longitudinal follow-up (7-456 months; median = 35). RESULTS Among 3,910 patients tested, 196 were LGI1-IgG positive, 51 were CASPR2-IgG positive, and 9 were dual positive. Cerebrospinal fluid testing was less sensitive than serum testing, detecting only 24 of 38 (63%) LGI1-IgG-positive and 5 of 6 (83%) CASPR2-IgG-positive patients. LGI1-IgG-positive specimens had higher voltage-gated potassium channel-IgG immunoprecipitation values (0.33nmol/l, range = 0.02-5.14) than CASPR2-IgG-positive specimens (0.10nmol/l, range = 0.00-0.45, p < 0.001). Of patients presenting with pain or peripheral nervous system (PNS) manifestations, 39% were LGI1-IgG seropositive (7% had solely neuropathy or pain). Multivariate analysis identified age as the only significant predictor of central nervous system (CNS) versus PNS involvement (>50 years; odds ratio = 15, p < 0.001). Paroxysmal dizziness spells (PDS), a unique LGI1-IgG accompaniment (14% of patients), frequently delayed the diagnosis. T2-mesiotemporal hyperintensity was more common in LGI1-IgG-positive (41%) than in CASPR2-IgG-positive patients (p = 0.033). T1-bright basal ganglia were confined to LGI1-IgG-positive patients with faciobrachial-dystonic seizures (9 of 39, 31%). Cancer was found in 44% of LGI1-IgG/CASPR2-IgG dual seropositive patients (one-third thymoma). Response to initial immunotherapy was favorable in 97%; mean modified Rankin score was 3 (range = 1-5) at onset and 1.74 (range = 0-6) at last follow-up, with 9% having severe refractory disability, 20% being asymptomatic, 28% receiving immunotherapy, and 58% receiving antiepileptic medication. INTERPRETATION Older age is a strong predictor of CNS involvement in patients seropositive for CASPR2-IgG or LGI1-IgG. Pain, peripheral manifestations, and stereotypic paroxysmal dizziness spells are common with LGI1-IgG. Response to initial immunotherapy is often favorable, but some patients remain severely disabled, requiring long-term immunotherapy and/or antiepileptic medications. Ann Neurol 2017;82:79-92.
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Affiliation(s)
- Avi Gadoth
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Sean J Pittock
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Divyanshu Dubey
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Andrew McKeon
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Jeff W Britton
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - John E Schmeling
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Aurelia Smith
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | | | | | - Daniel H Lachance
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Eoin P Flanagan
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Vanda A Lennon
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
| | - Christopher J Klein
- Neuroimmunology Laboratory, Department of Neurology, Mayo Clinic, Rochester, MN
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18
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Fang Z, Yang Y, Chen X, Zhang W, Xie Y, Chen Y, Liu Z, Yuan W. Advances in Autoimmune Epilepsy Associated with Antibodies, Their Potential Pathogenic Molecular Mechanisms, and Current Recommended Immunotherapies. Front Immunol 2017; 8:395. [PMID: 28487693 PMCID: PMC5403900 DOI: 10.3389/fimmu.2017.00395] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 03/21/2017] [Indexed: 01/17/2023] Open
Abstract
In this comprehensive article, we present an overview of some most common autoimmune antibodies believed to be potentially pathogenic for autoimmune epilepsies and elaborate their pathogenic mode of action in molecular levels based on the existing knowledge. Findings of the studies of immunemodulatory treatments for epilepsy are also discussed, and guidelines for immunotherapy are sorted out. We aim to summarize the emerging understanding of different pathogenic mechanisms of autoantibodies and clinical immunotherapy regimens to open up therapeutic possibilities for future optimum therapy. We conclude that early diagnosis of autoimmune epilepsy is of great significance, as early immune treatments have useful disease-modifying effects on some epilepsies and can facilitate the recovery.
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Affiliation(s)
- Zhiwei Fang
- Department of Neurology, Xinhua Hospital Affiliated to the Medical School of Shanghai Jiao Tong University, Shanghai, China.,School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Yunqi Yang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Zhiyuan College, Shanghai Jiao Tong University, Shanghai, China
| | - Xuan Chen
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Weiwang Zhang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Yangmei Xie
- Department of Neurology, Jinshan Hospital, Fudan University, Shanghai, China
| | - Yinghui Chen
- Department of Neurology, Jinshan Hospital, Fudan University, Shanghai, China
| | - Zhenguo Liu
- Department of Neurology, Xinhua Hospital Affiliated to the Medical School of Shanghai Jiao Tong University, Shanghai, China
| | - Weien Yuan
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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Dazzo E, Leonardi E, Belluzzi E, Malacrida S, Vitiello L, Greggio E, Tosatto SCE, Nobile C. Secretion-Positive LGI1 Mutations Linked to Lateral Temporal Epilepsy Impair Binding to ADAM22 and ADAM23 Receptors. PLoS Genet 2016; 12:e1006376. [PMID: 27760137 PMCID: PMC5070869 DOI: 10.1371/journal.pgen.1006376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/20/2016] [Indexed: 01/17/2023] Open
Abstract
Autosomal dominant lateral temporal epilepsy (ADTLE) is a focal epilepsy syndrome caused by mutations in the LGI1 gene, which encodes a secreted protein. Most ADLTE-causing mutations inhibit LGI1 protein secretion, and only a few secretion-positive missense mutations have been reported. Here we describe the effects of four disease-causing nonsynonymous LGI1 mutations, T380A, R407C, S473L, and R474Q, on protein secretion and extracellular interactions. Expression of LGI1 mutant proteins in cultured cells shows that these mutations do not inhibit protein secretion. This finding likely results from the lack of effects of these mutations on LGI1 protein folding, as suggested by 3D protein modelling. In addition, immunofluorescence and co-immunoprecipitation experiments reveal that all four mutations significantly impair interaction of LGI1 with the ADAM22 and ADAM23 receptors on the cell surface. These results support the existence of a second mechanism, alternative to inhibition of protein secretion, by which ADLTE-causing LGI1 mutations exert their loss-of-function effect extracellularly, and suggest that interactions of LGI1 with both ADAM22 and ADAM23 play an important role in the molecular mechanisms leading to ADLTE. Temporal lobe epilepsy is the most common form of focal epilepsy. It is frequently associated with structural brain abnormalities, but genetic forms caused by mutations in major genes have also been described. Autosomal dominant lateral temporal epilepsy (ADLTE) is a familial condition characterized by focal seizures with prominent auditory symptoms. ADLTE-causing mutations are found in the LGI1 gene in about 30% of affected families. LGI1 encodes a protein, LGI1, that is secreted by neurons. Most LGI1 mutations suppress protein secretion, thereby preventing protein function in the extracellular environment. In this paper, we examine the effects of four LGI1 mutations and show that they do not inhibit secretion of the LGI1 protein but impair its interaction with the neuronal receptors ADAM22 and ADAM23. In agreement with these findings, a three- dimensional model of the protein predicts that these mutations have no impact on LGI1 structure but instead may affect amino acids that are critical for interactions with ADAM receptors. Our results provide novel evidence for an extracellular mechanism through which mutant LGI1 proteins cause ADLTE and strengthen the importance of LGI1-ADAM22/23 protein complex in the mechanisms underlying ADLTE.
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Affiliation(s)
- Emanuela Dazzo
- CNR-Neuroscience Institute, Section of Padua, Padova, Italy
| | - Emanuela Leonardi
- Department of Woman and Child’s Health, University of Padua, Padova, Italy
| | - Elisa Belluzzi
- Department of Biology, University of Padua, Padova, Italy
| | - Sandro Malacrida
- Department of Biomedical Sciences, University of Padua, Padova, Italy
| | | | - Elisa Greggio
- Department of Biology, University of Padua, Padova, Italy
| | - Silvio C. E. Tosatto
- CNR-Neuroscience Institute, Section of Padua, Padova, Italy
- Department of Biomedical Sciences, University of Padua, Padova, Italy
| | - Carlo Nobile
- CNR-Neuroscience Institute, Section of Padua, Padova, Italy
- Department of Biomedical Sciences, University of Padua, Padova, Italy
- * E-mail:
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Boillot M, Baulac S. Genetic models of focal epilepsies. J Neurosci Methods 2016; 260:132-43. [DOI: 10.1016/j.jneumeth.2015.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/06/2023]
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Yokoi N, Fukata Y, Kase D, Miyazaki T, Jaegle M, Ohkawa T, Takahashi N, Iwanari H, Mochizuki Y, Hamakubo T, Imoto K, Meijer D, Watanabe M, Fukata M. Chemical corrector treatment ameliorates increased seizure susceptibility in a mouse model of familial epilepsy. Nat Med 2014; 21:19-26. [PMID: 25485908 DOI: 10.1038/nm.3759] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/23/2014] [Indexed: 12/12/2022]
Abstract
Epilepsy is one of the most common and intractable brain disorders. Mutations in the human gene LGI1, encoding a neuronal secreted protein, cause autosomal dominant lateral temporal lobe epilepsy (ADLTE). However, the pathogenic mechanisms of LGI1 mutations remain unclear. We classified 22 reported LGI1 missense mutations as either secretion defective or secretion competent, and we generated and analyzed two mouse models of ADLTE encoding mutant proteins representative of the two groups. The secretion-defective LGI1(E383A) protein was recognized by the ER quality-control machinery and prematurely degraded, whereas the secretable LGI1(S473L) protein abnormally dimerized and was selectively defective in binding to one of its receptors, ADAM22. Both mutations caused a loss of function, compromising intracellular trafficking or ligand activity of LGI1 and converging on reduced synaptic LGI1-ADAM22 interaction. A chemical corrector, 4-phenylbutyrate (4PBA), restored LGI1(E383A) folding and binding to ADAM22 and ameliorated the increased seizure susceptibility of the LGI1(E383A) model mice. This study establishes LGI1-related epilepsy as a conformational disease and suggests new therapeutic options for human epilepsy.
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Affiliation(s)
- Norihiko Yokoi
- 1] Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan. [2] Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Yuko Fukata
- 1] Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan. [2] Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Daisuke Kase
- Division of Neural Signaling, Department of Information Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan
| | - Taisuke Miyazaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Martine Jaegle
- Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Toshika Ohkawa
- 1] Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan. [2] Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Naoki Takahashi
- Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan
| | - Hiroko Iwanari
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Yasuhiro Mochizuki
- 1] Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan. [2] Komaba Open Lab, PeptiDream Incorporation, Tokyo, Japan
| | - Takao Hamakubo
- Department of Quantitative Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Keiji Imoto
- 1] Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan. [2] Division of Neural Signaling, Department of Information Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan
| | - Dies Meijer
- 1] Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands. [2] Centre for Neuroregeneration, University of Edinburgh, Edinburgh, UK
| | - Masahiko Watanabe
- 1] Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan. [2] Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo, Japan
| | - Masaki Fukata
- 1] Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Japan. [2] Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
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Silva J, Sharma S, Cowell JK. Homozygous Deletion of the LGI1 Gene in Mice Leads to Developmental Abnormalities Resulting in Cortical Dysplasia. Brain Pathol 2014; 25:587-97. [PMID: 25346110 DOI: 10.1111/bpa.12225] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 10/21/2014] [Indexed: 01/02/2023] Open
Abstract
LGI1 mutations lead to an autosomal dominant form of epilepsy. Lgi1 mutant null mice develop seizures and show abnormal neuronal excitability. A fine structure analysis of the cortex in these mice demonstrated a subtle cortical dysplasia, preferentially affecting layers II-IV, associated with increased Foxp2 and Cux1-expressing neurons leading to blurring of the cortical layers. The hypercellularity observed in the null cortex resulted from an admixture of highly branched mature pyramidal neurons with short and poorly aligned axons as revealed by Golgi staining and immature small neurons with branched disoriented dendrites with reduced spine density and undersized, morphologically altered and round-headed spines. In vitro, hippocampal neurons revealed poor neurite outgrowth in null mice as well as reduced synapse formation. Electron microscopy demonstrated reduced spine-localized asymmetric (axospinous) synapses with postsynaptic densities and vesicle-loaded synapses in the mutant null cortex. The overall pathology in the null mice suggested cortical dyslamination most likely because of mislocalization of late-born neurons, with an admixture of those carrying suboptimally developed axons and dendrites with reduced functional synapses with normal neurons. Our study suggests that LGI1 has a role in regulating cortical development, which is increasingly becoming recognized as one of the causes of idiopathic epilepsy.
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Affiliation(s)
- Jeane Silva
- Cancer Center, Georgia Regents University, Augusta, GA
| | - Suash Sharma
- Cancer Center, Georgia Regents University, Augusta, GA.,Department of Pathology, Georgia Regents University, Augusta, GA
| | - John K Cowell
- Cancer Center, Georgia Regents University, Augusta, GA.,Department of Pathology, Georgia Regents University, Augusta, GA
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Boillot M, Huneau C, Marsan E, Lehongre K, Navarro V, Ishida S, Dufresnois B, Ozkaynak E, Garrigue J, Miles R, Martin B, Leguern E, Anderson MP, Baulac S. Glutamatergic neuron-targeted loss of LGI1 epilepsy gene results in seizures. ACTA ACUST UNITED AC 2014; 137:2984-96. [PMID: 25234641 DOI: 10.1093/brain/awu259] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Leucin-rich, glioma inactivated 1 (LGI1) is a secreted protein linked to human seizures of both genetic and autoimmune aetiology. Mutations in the LGI1 gene are responsible for autosomal dominant temporal lobe epilepsy with auditory features, whereas LGI1 autoantibodies are involved in limbic encephalitis, an acquired epileptic disorder associated with cognitive impairment. We and others previously reported that Lgi1-deficient mice have early-onset spontaneous seizures leading to premature death at 2-3 weeks of age. Yet, where and when Lgi1 deficiency causes epilepsy remains unknown. To address these questions, we generated Lgi1 conditional knockout (cKO) mice using a set of universal Cre-driver mouse lines. Selective deletion of Lgi1 was achieved in glutamatergic pyramidal neurons during embryonic (Emx1-Lgi1cKO) or late postnatal (CaMKIIα-Lgi1cKO) developmental stages, or in gamma amino butyric acidergic (GABAergic) parvalbumin interneurons (PV-Lgi1cKO). Emx1-Lgi1cKO mice displayed early-onset and lethal seizures, whereas CaMKIIα-Lgi1cKO mice presented late-onset occasional seizures associated with variable reduced lifespan. In contrast, neither spontaneous seizures nor increased seizure susceptibility to convulsant were observed when Lgi1 was deleted in parvalbumin interneurons. Together, these data showed that LGI1 depletion restricted to pyramidal cells is sufficient to generate seizures, whereas seizure thresholds were unchanged after depletion in gamma amino butyric acidergic parvalbumin interneurons. We suggest that LGI1 secreted from excitatory neurons, but not parvalbumin inhibitory neurons, makes a major contribution to the pathogenesis of LGI1-related epilepsies. Our data further indicate that LGI1 is required from embryogenesis to adulthood to achieve proper circuit functioning.
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Affiliation(s)
- Morgane Boillot
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Clément Huneau
- 5 Université de Rennes 1, LTSI, F-35000, Rennes, France 6 INSERM, U1099, F-35000, Rennes, France
| | - Elise Marsan
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Katia Lehongre
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Vincent Navarro
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France 7 AP-HP, Hôpital de la Pitié-Salpêtrière, Epilepsy Unit, F-75013, Paris, France
| | - Saeko Ishida
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Béatrice Dufresnois
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Ekim Ozkaynak
- 8 Departments of Neurology and Pathology, Beth Israel Deaconess Medical Centre and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Jérôme Garrigue
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Richard Miles
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Benoit Martin
- 5 Université de Rennes 1, LTSI, F-35000, Rennes, France 6 INSERM, U1099, F-35000, Rennes, France
| | - Eric Leguern
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France 9 AP-HP, Hôpital de la Pitié-Salpêtrière, Département de Génétique et de Cytogénétique, F-75013, Paris, France
| | - Matthew P Anderson
- 8 Departments of Neurology and Pathology, Beth Israel Deaconess Medical Centre and Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Stéphanie Baulac
- 1 INSERM, U 1127, F-75013, Paris, France 2 CNRS, UMR 7225, F-75013, Paris, France 3 Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, ICM, F-75013 Paris, France 4 Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
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Kegel L, Jaegle M, Driegen S, Aunin E, Leslie K, Fukata Y, Watanabe M, Fukata M, Meijer D. Functional phylogenetic analysis of LGI proteins identifies an interaction motif crucial for myelination. Development 2014; 141:1749-56. [PMID: 24715463 DOI: 10.1242/dev.107995] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The cellular interactions that drive the formation and maintenance of the insulating myelin sheath around axons are only partially understood. Leucine-rich glioma-inactivated (LGI) proteins play important roles in nervous system development and mutations in their genes have been associated with epilepsy and amyelination. Their function involves interactions with ADAM22 and ADAM23 cell surface receptors, possibly in apposing membranes, thus attenuating cellular interactions. LGI4-ADAM22 interactions are required for axonal sorting and myelination in the developing peripheral nervous system (PNS). Functional analysis revealed that, despite their high homology and affinity for ADAM22, LGI proteins are functionally distinct. To dissect the key residues in LGI proteins required for coordinating axonal sorting and myelination in the developing PNS, we adopted a phylogenetic and computational approach and demonstrate that the mechanism of action of LGI4 depends on a cluster of three amino acids on the outer surface of the LGI4 protein, thus providing a structural basis for the mechanistic differences in LGI protein function in nervous system development and evolution.
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Affiliation(s)
- Linde Kegel
- Erasmus University Medical Center, Biomedical Sciences, Departments of Genetics and Cell Biology, Rotterdam 3015GE, The Netherlands
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25
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van Coevorden-Hameete MH, de Graaff E, Titulaer MJ, Hoogenraad CC, Sillevis Smitt PAE. Molecular and cellular mechanisms underlying anti-neuronal antibody mediated disorders of the central nervous system. Autoimmun Rev 2014; 13:299-312. [PMID: 24225076 DOI: 10.1016/j.autrev.2013.10.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 10/30/2013] [Indexed: 12/31/2022]
Abstract
Over the last decade multiple autoantigens located on the plasma membrane of neurons have been identified. Neuronal surface antigens include molecules directly involved in neurotransmission and excitability. Binding of the antibody to the antigen may directly alter the target protein's function, resulting in neurological disorders. The often striking reversibility of symptoms following early aggressive immunotherapy supports a pathogenic role for autoantibodies to neuronal surface antigens. In order to better understand and treat these neurologic disorders it is important to gain insight in the underlying mechanisms of antibody pathogenicity. In this review we discuss the clinical, circumstantial, in vitro and in vivo evidence for neuronal surface antibody pathogenicity and the possible underlying cellular and molecular mechanisms. This review shows that antibodies to neuronal surface antigens are often directed at conformational epitopes located in the extracellular domain of the antigen. The conformation of the epitope can be affected by specific posttranslational modifications. This may explain the distinct clinical phenotypes that are seen in patients with antibodies to antigens that are expressed throughout the brain. Furthermore, it is likely that there is a heterogeneous antibody population, consisting of different IgG subtypes and directed at multiple epitopes located in an immunogenic region. Binding of these antibodies may result in different pathophysiological mechanisms occurring in the same patient, together contributing to the clinical syndrome. Unraveling the predominant mechanism in each distinct antigen could provide clues for therapeutic interventions.
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Affiliation(s)
- M H van Coevorden-Hameete
- Department of Biology, Division of Cell Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - E de Graaff
- Department of Biology, Division of Cell Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - M J Titulaer
- Department of Neurology, Erasmus MC, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
| | - C C Hoogenraad
- Department of Biology, Division of Cell Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - P A E Sillevis Smitt
- Department of Neurology, Erasmus MC, 's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
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Abstract
Epilepsy affects almost 1% of the population, and yet the pathophysiology of this disorder is unknown in the majority of the cases. Recently, a number of mutations in different genes were identified, mostly in cases of familial epilepsy with a Mendelian mode of inheritance. The majority of these genes code for voltage- or ligand-gated ion channels. Interestingly, not only generalized epilepsies, but also focal epilepsies were shown to be caused by mutated genes, which in some cases are expressed ubiquitously in the brain. This review will focus on the monogenic familial epilepsies and the clinical and molecular aspects of these diseases.
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Affiliation(s)
- Danielle M Andrade
- University of Toronto, Division of Neurology, Krembil Neuroscience Centre, Toronto Western Hospital, Toronto, Canada.
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28
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Baulac S. Genetics advances in autosomal dominant focal epilepsies. PROGRESS IN BRAIN RESEARCH 2014; 213:123-39. [DOI: 10.1016/b978-0-444-63326-2.00007-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Winther M, Walmod PS. Neural cell adhesion molecules belonging to the family of leucine-rich repeat proteins. ADVANCES IN NEUROBIOLOGY 2014; 8:315-95. [PMID: 25300143 DOI: 10.1007/978-1-4614-8090-7_14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Leucine-rich repeats (LRRs) are motifs that form protein-ligand interaction domains. There are approximately 140 human genes encoding proteins with extracellular LRRs. These encode cell adhesion molecules (CAMs), proteoglycans, G-protein-coupled receptors, and other types of receptors. Here we give a brief description of 36 proteins with extracellular LRRs that all can be characterized as CAMs or putative CAMs expressed in the nervous system. The proteins are involved in multiple biological processes in the nervous system including the proliferation and survival of cells, neuritogenesis, axon guidance, fasciculation, myelination, and the formation and maintenance of synapses. Moreover, the proteins are functionally implicated in multiple diseases including cancer, hearing impairment, glaucoma, Alzheimer's disease, multiple sclerosis, Parkinson's disease, autism spectrum disorders, schizophrenia, and obsessive-compulsive disorders. Thus, LRR-containing CAMs constitute a large group of proteins of pivotal importance for the development, maintenance, and regeneration of the nervous system.
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Pitkänen A, Ndode-Ekane XE, Łukasiuk K, Wilczynski GM, Dityatev A, Walker MC, Chabrol E, Dedeurwaerdere S, Vazquez N, Powell EM. Neural ECM and epilepsy. PROGRESS IN BRAIN RESEARCH 2014; 214:229-62. [DOI: 10.1016/b978-0-444-63486-3.00011-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Abstract
Mutations in the LGI1 gene predispose to autosomal dominant lateral temporal lobe epilepsy, a rare hereditary form with incomplete penetrance and associated with acoustic auras. LGI1 is not a structural component of an ion channel like most epilepsy-related genes, but is a secreted protein. Mutant null mice exhibit early-onset seizures, and electrophysiological analysis shows abnormal synaptic transmission. LGI1 binds to ADAM23 on the presynaptic membrane and ADAM22 on the postsynaptic membrane, further implicating it in regulating the strength of synaptic transmission. Patients with limbic encephalitis show autoantibodies against LGI1 and develop seizures, supporting a role for LGI1 in synapse transmission in the post developmental brain. LGI1, however, also seems to be involved in aspects of neurite development and dendritic pruning, suggesting an additional role in corticogenesis. LGI1 is also involved in cell movement and suppression of dendritic outgrowth in in vitro systems, possibly involving actin cytoskeleton dynamics. Expression patterns in embryonic development correspond to areas of neuronal migration. Loss of LGI1 expression also impacts on myelination of the central and peripheral nervous systems. In zebrafish embryos, knockdown of lgi1a leads to a seizure-like behavior and abnormal brain development, providing a system to study its role in early embryogenesis. Despite being implicated in a role in both synapse transmission and neuronal development, how LGI1 predisposes to epilepsy is still largely unknown. It appears, however, that LGI1 may function differently in a cell context-specific manner, implying a complex involvement in brain development and function that remains to be defined.
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Affiliation(s)
- John K Cowell
- Georgia Regents University Cancer Center, Augusta, GA, USA.
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32
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Abstract
The development and function of the vertebrate nervous system depend on specific interactions between different cell types. Two examples of such interactions are synaptic transmission and myelination. LGI1-4 (leucine-rich glioma inactivated proteins) play important roles in these processes. They are secreted proteins consisting of an LRR (leucine-rich repeat) domain and a so-called epilepsy-associated or EPTP (epitempin) domain. Both domains are thought to function in protein–protein interactions. The first LGI gene to be identified, LGI1, was found at a chromosomal translocation breakpoint in a glioma cell line. It was subsequently found mutated in ADLTE (autosomal dominant lateral temporal (lobe) epilepsy) also referred to as ADPEAF (autosomal dominant partial epilepsy with auditory features). LGI1 protein appears to act at synapses and antibodies against LGI1 may cause the autoimmune disorder limbic encephalitis. A similar function in synaptic remodelling has been suggested for LGI2, which is mutated in canine Benign Familial Juvenile Epilepsy. LGI4 is required for proliferation of glia in the peripheral nervous system and binds to a neuronal receptor, ADAM22, to foster ensheathment and myelination of axons by Schwann cells. Thus, LGI proteins play crucial roles in nervous system development and function and their study is highly important, both to understand their biological functions and for their therapeutic potential. Here, we review our current knowledge about this important family of proteins, and the progress made towards understanding their functions.
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Michelucci R, Pasini E, Riguzzi P, Volpi L, Dazzo E, Nobile C. Genetics of epilepsy and relevance to current practice. Curr Neurol Neurosci Rep 2012; 12:445-55. [PMID: 22618127 DOI: 10.1007/s11910-012-0281-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Genetic factors are likely to play a major role in many epileptic conditions, spanning from classical idiopathic (genetic) generalized epilepsies to epileptic encephalopathies and focal epilepsies. In this review we describe the genetic advances in progressive myoclonus epilepsies, which are strictly monogenic disorders, genetic generalized epilepsies, mostly exhibiting complex genetic inheritance, and SCN1A-related phenotypes, namely genetic generalized epilepsy with febrile seizure plus and Dravet syndrome. Particular attention is devoted to a form of familial focal epilepsies, autosomal-dominant lateral temporal epilepsy, which is a model of non-ion genetic epilepsies. This condition is associated with mutations of the LGI1 gene, whose protein is secreted from the neurons and exerts its action on a number of targets, influencing cortical development and neuronal maturation.
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Affiliation(s)
- Roberto Michelucci
- Unit of Neurology, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Via Altura 3, 40139, Bologna, Italy.
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34
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Hwang SK, Hirose S. Genetics of temporal lobe epilepsy. Brain Dev 2012; 34:609-16. [PMID: 22105092 DOI: 10.1016/j.braindev.2011.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 10/14/2011] [Accepted: 10/22/2011] [Indexed: 01/10/2023]
Abstract
The most common partial epilepsy, temporal lobe epilepsy (TLE) consists of a heterogeneous group of seizure disorders originating in the temporal lobe. TLE had been thought to develop as a result of acquired structural problems in the temporal lobe. During the past two decades, there has been growing evidence of the important influence of genetic factors, and familial and non-lesional TLE have been increasingly described. Here, we focus on the genetics of TLE and review related genes which have been studied recently. Although its molecular mechanisms are still poorly understood, TLE genetics is a fertile field, awaiting more research.
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Affiliation(s)
- Su-Kyeong Hwang
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
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Kusuzawa S, Honda T, Fukata Y, Fukata M, Kanatani S, Tanaka DH, Nakajima K. Leucine-rich glioma inactivated 1 (Lgi1), an epilepsy-related secreted protein, has a nuclear localization signal and localizes to both the cytoplasm and the nucleus of the caudal ganglionic eminence neurons. Eur J Neurosci 2012; 36:2284-92. [DOI: 10.1111/j.1460-9568.2012.08129.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Baulac S, Ishida S, Mashimo T, Boillot M, Fumoto N, Kuwamura M, Ohno Y, Takizawa A, Aoto T, Ueda M, Ikeda A, LeGuern E, Takahashi R, Serikawa T. A rat model for LGI1-related epilepsies. Hum Mol Genet 2012; 21:3546-57. [PMID: 22589250 DOI: 10.1093/hmg/dds184] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mutations of the leucine-rich glioma-inactivated 1 (LGI1) gene cause an autosomal dominant partial epilepsy with auditory features also known as autosomal-dominant lateral temporal lobe epilepsy. LGI1 is also the main antigen present in sera and cerebrospinal fluids of patients with limbic encephalitis and seizures, highlighting its importance in a spectrum of epileptic disorders. LGI1 encodes a neuronal secreted protein, whose brain function is still poorly understood. Here, we generated, by ENU (N-ethyl-N-nitrosourea) mutagenesis, Lgi1-mutant rats carrying a missense mutation (L385R). We found that the L385R mutation prevents the secretion of Lgi1 protein by COS7 transfected cells. However, the L385R-Lgi1 protein was found at low levels in the brains and cultured neurons of Lgi1-mutant rats, suggesting that mutant protein may be destabilized in vivo. Studies on the behavioral phenotype and intracranial electroencephalographic signals from Lgi1-mutant rats recalled several features of the human genetic disorder. We show that homozygous Lgi1-mutant rats (Lgi1(L385R/L385R)) generated early-onset spontaneous epileptic seizures from P10 and died prematurely. Heterozygous Lgi1-mutant rats (Lgi1(+/L385R)) were more susceptible to sound-induced, generalized tonic-clonic seizures than control rats. Audiogenic seizures were suppressed by antiepileptic drugs such as carbamazepine, phenytoin and levetiracetam, which are commonly used to treat partial seizures, but not by the prototypic absence seizure drug, ethosuximide. Our findings provide the first rat model with a missense mutation in Lgi1 gene, an original model complementary to knockout mice. This study revealed that LGI1 disease-causing missense mutations might cause a depletion of the protein in neurons, and not only a failure of Lgi1 secretion.
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Smith SEP, Xu L, Kasten MR, Anderson MP. Mutant LGI1 inhibits seizure-induced trafficking of Kv4.2 potassium channels. J Neurochem 2012; 120:611-21. [PMID: 22122031 DOI: 10.1111/j.1471-4159.2011.07605.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Activity-dependent redistribution of ion channels mediates neuronal circuit plasticity and homeostasis, and could provide pro-epileptic or compensatory anti-epileptic responses to a seizure. Thalamocortical neurons transmit sensory information to the cerebral cortex and through reciprocal corticothalamic connections are intensely activated during a seizure. Therefore, we assessed whether a seizure alters ion channel surface expression and consequent neurophysiologic function of thalamocortical neurons. We report a seizure triggers a rapid (<2h) decrease of excitatory postsynaptic current (EPSC)-like current-induced phasic firing associated with increased transient A-type K(+) current. Seizures also rapidly redistributed the A-type K(+) channel subunit Kv4.2 to the neuronal surface implicating a molecular substrate for the increased K(+) current. Glutamate applied in vitro mimicked the effect, suggesting a direct effect of glutamatergic transmission. Importantly, leucine-rich glioma-inactivated-1 (LGI1), a secreted synaptic protein mutated to cause human partial epilepsy, regulated this seizure-induced circuit response. Human epilepsy-associated dominant-negative-truncated mutant LGI1 inhibited the seizure-induced suppression of phasic firing, increase of A-type K(+) current, and recruitment of Kv4.2 surface expression (in vivo and in vitro). The results identify a response of thalamocortical neurons to seizures involving Kv4.2 surface recruitment associated with dampened phasic firing. The results also identify impaired seizure-induced increases of A-type K(+) current as an additional defect produced by the autosomal dominant lateral temporal lobe epilepsy gene mutant that might contribute to the seizure disorder.
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Affiliation(s)
- Stephen E P Smith
- Departments of Neurology and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Ho YY, Ionita-Laza I, Ottman R. Domain-dependent clustering and genotype-phenotype analysis of LGI1 mutations in ADPEAF. Neurology 2012; 78:563-8. [PMID: 22323750 DOI: 10.1212/wnl.0b013e318247ccbf] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE In families with autosomal dominant partial epilepsy with auditory features (ADPEAF) with mutations in the LGI1 gene, we evaluated clustering of mutations within the gene and associations of penetrance and phenotypic features with mutation location and predicted effect (truncation or missense). METHODS We abstracted clinical and molecular information from the literature for all 36 previously published ADPEAF families with LGI1 mutations. We used a sliding window approach to analyze mutation clustering within the gene. Each mutation was mapped to one of the gene's 2 major functional domains, N-terminal leucine-rich repeats (LRRs) and C-terminal epitempin (EPTP) repeats, and classified according to predicted effect on the encoded protein (truncation vs missense). Analyses of phenotypic features (age at onset and occurrence of auditory symptoms) in relation to mutation site and predicted effect included 160 patients with idiopathic focal unprovoked seizures from the 36 families. RESULTS ADPEAF-causing mutations clustered significantly in the LRR domain (exons 3-5) of LGI1 (p = 0.026). Auditory symptoms were less frequent in individuals with truncation mutations in the EPTP domain than in those with other mutation type/domain combinations (58% vs 80%, p = 0.018). CONCLUSION The LRR region of the LGI1 gene is likely to play a major role in pathogenesis of ADPEAF.
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Affiliation(s)
- Yuan-Yuan Ho
- Department of Psychiatry, Columbia University, New York, NY, USA
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Teng Y, Xie X, Walker S, Saxena M, Kozlowski DJ, Mumm JS, Cowell JK. Loss of zebrafish lgi1b leads to hydrocephalus and sensitization to pentylenetetrazol induced seizure-like behavior. PLoS One 2011; 6:e24596. [PMID: 22053218 PMCID: PMC3203530 DOI: 10.1371/journal.pone.0024596] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/15/2011] [Indexed: 11/19/2022] Open
Abstract
Mutations in the LGI1 gene predispose to a hereditary epilepsy syndrome and is the first gene associated with this disease which does not encode an ion channel protein. In zebrafish, there are two paralogs of the LGI1 gene, lgi1a and lgi1b. Knockdown of lgi1a results in a seizure-like hyperactivity phenotype with associated developmental abnormalities characterized by cellular loss in the eyes and brain. We have now generated knockdown morphants for the lgi1b gene which also show developmental abnormalities but do not show a seizure-like behavior. Instead, the most striking phenotype involves significant enlargement of the ventricles (hydrocephalus). As shown for the lgi1a morphants, however, lgi1b morphants are also sensitized to PTZ-induced hyperactivity. The different phenotypes between the two lgi1 morphants support a subfunctionalization model for the two paralogs.
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Affiliation(s)
- Yong Teng
- GHSU Cancer Center, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Xiayang Xie
- Department of Cellular Biology and Anatomy, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Vision Discovery Institute, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Steven Walker
- Department of Cellular Biology and Anatomy, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Vision Discovery Institute, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Meera Saxena
- Luminomics Inc, Augusta, Georgia, United States of America
| | - David J. Kozlowski
- Department of Cellular Biology and Anatomy, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Program in Developmental Neurobiology, Institute of Molecular Medicine and Genetics, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Jeff S. Mumm
- Department of Cellular Biology and Anatomy, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Vision Discovery Institute, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - John K. Cowell
- GHSU Cancer Center, School of Medicine, Georgia Health Sciences University, Augusta, Georgia, United States of America
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Autoantibodies associated with diseases of the CNS: new developments and future challenges. Lancet Neurol 2011; 10:759-72. [PMID: 21777830 DOI: 10.1016/s1474-4422(11)70096-5] [Citation(s) in RCA: 351] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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de Wit J, Hong W, Luo L, Ghosh A. Role of leucine-rich repeat proteins in the development and function of neural circuits. Annu Rev Cell Dev Biol 2011; 27:697-729. [PMID: 21740233 DOI: 10.1146/annurev-cellbio-092910-154111] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The nervous system consists of an ensemble of billions of neurons interconnected in a highly specific pattern that allows proper propagation and integration of neural activities. The organization of these specific connections emerges from sequential developmental events including axon guidance, target selection, and synapse formation. These events critically rely on cell-cell recognition and communication mediated by cell-surface ligands and receptors. Recent studies have uncovered central roles for leucine-rich repeat (LRR) domain-containing proteins, not only in organizing neural connectivity from axon guidance to target selection to synapse formation, but also in various nervous system disorders. Their versatile LRR domains, in particular, serve as key sites for interactions with a wide diversity of binding partners. Here, we focus on a few exquisite examples of secreted or membrane-associated LRR proteins in Drosophila and mammals and review the mechanisms by which they regulate diverse aspects of nervous system development and function.
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Affiliation(s)
- Joris de Wit
- Neurobiology Section, Division of Biology, University of California, San Diego, La Jolla, California 92093-0366, USA
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Silva J, Wang G, Cowell JK. The temporal and spatial expression pattern of the LGI1 epilepsy predisposition gene during mouse embryonic cranial development. BMC Neurosci 2011; 12:43. [PMID: 21569517 PMCID: PMC3120723 DOI: 10.1186/1471-2202-12-43] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 05/13/2011] [Indexed: 11/20/2022] Open
Abstract
Background Mutations in the LGI1 gene predispose to a rare, hereditary form of temporal epilepsy. Currently, little is known about the temporal and spatial expression pattern of Lgi1 during normal embryogenesis and so to define this more clearly we used a transgenic mouse line that expresses GFP under the control of Lgi1 cis-regulatory elements. Results During embryonic brain growth, high levels of Lgi1 expression were found in the surface ectoderm, the neuroepithelium, mesenchymal connective tissue, hippocampus, and sensory organs, such as eye, tongue, and the olfactory bulb. Lgi1 was also found in the cranial nerve nuclei and ganglia, such as vestibular, trigeminal, and dorsal ganglia. Expression of Lgi1 followed an orchestrated pattern during mouse development becoming more subdued in areas of the neocortex of the mid- and hind-brain in early postnatal animals, although high expression levels were retained in the choroid plexus and hippocampus. In late postnatal stages, Lgi1 expression continued to be detected in many areas in the brain including, hippocampus, paraventricular thalamic nuclei, inferior colliculus, and the cerebral aqueduct. We also showed that Lgi1-expressing cells co-express nestin, DCX, and beta-III tubulin suggesting that Lgi1-expressing cells are migratory neuroblasts. Conclusion These observations imply that Lgi1 may have a role in establishing normal brain architecture and neuronal functions during brain development suggesting that it may be involved in neurogenesis and neuronal plasticity, which become more specifically defined in the adult animal.
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Affiliation(s)
- Jeane Silva
- GHSU Cancer Center, School of Medicine, Georgia Health Sciences University, Augusta 30912, USA
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Di Bonaventura C, Operto FF, Busolin G, Egeo G, D'Aniello A, Vitello L, Smaniotto G, Furlan S, Diani E, Michelucci R, Giallonardo AT, Coppola G, Nobile C. Low penetrance and effect on protein secretion of LGI1 mutations causing autosomal dominant lateral temporal epilepsy. Epilepsia 2011; 52:1258-64. [PMID: 21504429 DOI: 10.1111/j.1528-1167.2011.03071.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE To describe the clinical and genetic findings of four families with autosomal dominant lateral temporal epilepsy. METHODS A personal and family history was obtained from each affected and unaffected subject along with a physical and neurologic examination. Routine electroencephalography and magnetic resonance imaging (MRI) studies were performed in almost all patients. DNAs from family members were screened for LGI1 mutations. The effects of mutations on Lgi1 protein secretion were determined in transfected culture cells. KEY FINDINGS The four families included a total of 11 patients (two deceased), six of whom had lateral temporal epilepsy with auditory aura. Age at onset was in the second decade of life; seizures were well controlled by antiepileptic treatment and MRI studies were normal. We found two pathogenic LGI1 mutations with uncommonly low penetrance: the R136W mutation, previously detected in a sporadic case with telephone-induced partial seizures, gave rise to the epileptic phenotype in three of nine mutation carriers in one family; the novel C179R mutation caused epilepsy in an isolated patient from a family where the mutation segregated. Another novel pathogenic mutation, I122T, and a nonsynonymous variant, I359V, were found in the two other families. Protein secretion tests showed that the R136W and I122T mutations inhibited secretion of the mutant proteins, whereas I359V had no effect on protein secretion; C179R was not tested, because of its predictable effect on protein folding. SIGNIFICANCE These findings suggest that some LGI1 mutations may have a weak penetrance in families with complex inheritance pattern, or isolated patients, and that the protein secretion test, together with other predictive criteria, may help recognize pathogenic LGI1 mutations.
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Leonardi E, Andreazza S, Vanin S, Busolin G, Nobile C, Tosatto SCE. A computational model of the LGI1 protein suggests a common binding site for ADAM proteins. PLoS One 2011; 6:e18142. [PMID: 21479274 PMCID: PMC3066209 DOI: 10.1371/journal.pone.0018142] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 02/23/2011] [Indexed: 01/06/2023] Open
Abstract
Mutations of human leucine-rich glioma inactivated (LGI1) gene encoding the epitempin protein cause autosomal dominant temporal lateral epilepsy (ADTLE), a rare familial partial epileptic syndrome. The LGI1 gene seems to have a role on the transmission of neuronal messages but the exact molecular mechanism remains unclear. In contrast to other genes involved in epileptic disorders, epitempin shows no homology with known ion channel genes but contains two domains, composed of repeated structural units, known to mediate protein-protein interactions.A three dimensional in silico model of the two epitempin domains was built to predict the structure-function relationship and propose a functional model integrating previous experimental findings. Conserved and electrostatic charged regions of the model surface suggest a possible arrangement between the two domains and identifies a possible ADAM protein binding site in the β-propeller domain and another protein binding site in the leucine-rich repeat domain. The functional model indicates that epitempin could mediate the interaction between proteins localized to different synaptic sides in a static way, by forming a dimer, or in a dynamic way, by binding proteins at different times.The model was also used to predict effects of known disease-causing missense mutations. Most of the variants are predicted to alter protein folding while several other map to functional surface regions. In agreement with experimental evidence, this suggests that non-secreted LGI1 mutants could be retained within the cell by quality control mechanisms or by altering interactions required for the secretion process.
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Affiliation(s)
| | | | - Stefano Vanin
- Department of Biology, University of Padova, Padova, Italy
- School of Applied Science, University of Huddersfield, Huddersfield, United Kingdom
| | - Giorgia Busolin
- Institute of Neurosciences, Consiglio Nazionale delle Ricerche (CNR), Padova, Italy
| | - Carlo Nobile
- Institute of Neurosciences, Consiglio Nazionale delle Ricerche (CNR), Padova, Italy
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Silva J, Sharma S, Hughes B, Yu YE, Cowell JK. Homozygous inactivation of the LGI1 gene results in hypomyelination in the peripheral and central nervous systems. J Neurosci Res 2010; 88:3328-36. [PMID: 20857514 PMCID: PMC3885985 DOI: 10.1002/jnr.22496] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mutations in the LGI1 gene in humans predispose to the development of autosomal dominant partial epilepsy with auditory features (ADPEAF). Homozygous inactivation of the Lgi1 gene in mice results in an epilepsy phenotype characterized by clonic seizures within 2-3 weeks after birth. Before onset of seizures, the 2-3-week-old null mutant mice show poor locomotor activity and neuromuscular strength. EM analysis of the sciatic nerve demonstrates impaired myelination of axons in the peripheral nervous system. Although heterozygous mutant mice do not show any locomotor phenotypes, they also demonstrate an intermediate level of hypomyelination compared with the wild-type mice. Hypomyelination was also observed in the central nervous system, which, although relatively mild, was still significantly different from that of the wild-type mice. These data suggest a role for LGI1 in the myelination functions of Schwann cells and oligodendrocytes.
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Affiliation(s)
- Jeane Silva
- MCG Cancer Center, School of Medicine, Medical College of Georgia, Augusta, Georgia 30912, USA
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Limviphuvadh V, Chua LL, Rahim RAAB, Eisenhaber F, Maurer-Stroh S, Adhikari S. Similarity of molecular phenotype between known epilepsy gene LGI1 and disease candidate gene LGI2. BMC BIOCHEMISTRY 2010; 11:39. [PMID: 20863412 PMCID: PMC2949613 DOI: 10.1186/1471-2091-11-39] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 09/24/2010] [Indexed: 11/20/2022]
Abstract
Background The LGI2 (leucine-rich, glioma inactivated 2) gene, a prime candidate for partial epilepsy with pericentral spikes, belongs to a family encoding secreted, beta-propeller domain proteins with EPTP/EAR epilepsy-associated repeats. In another family member, LGI1 (leucine-rich, glioma inactivated 1) mutations are responsible for autosomal dominant lateral temporal epilepsy (ADLTE). Because a few LGI1 disease mutations described in the literature cause secretion failure, we experimentally analyzed the secretion efficiency and subcellular localization of several LGI1 and LGI2 mutant proteins corresponding to observed non-synonymous single nucleotide polymorphisms (nsSNPs) affecting the signal peptide, the leucine-rich repeats and the EAR propeller. Results Mapping of disease-causing mutations in the EAR domain region onto a 3D-structure model shows that many of these mutations co-localize at an evolutionary conserved surface region of the propeller. We find that wild-type LGI2 is secreted to the extracellular medium in glycosylated form similarly to LGI1, whereas several mutant proteins tested in this study are secretion-deficient and accumulate in the endoplasmic reticulum. Interestingly, mutations at structurally homologous positions in the EAR domain have the same effect on secretion in LGI1 and LGI2. Conclusions This similarity of experimental mislocalization phenotypes for mutations at homologous positions of LGI2 and the established epilepsy gene LGI1 suggests that both genes share a potentially common molecular pathogenesis mechanism that might be the reason for genotypically distinct but phenotypically related forms of epilepsy.
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Affiliation(s)
- Vachiranee Limviphuvadh
- Bioinformatics Institute, Agency for Science, Technology and Research, 30 Biopolis Street, #07-01 Matrix, 138671 Singapore.
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Teng Y, Xie X, Walker S, Rempala G, Kozlowski DJ, Mumm JS, Cowell JK. Knockdown of zebrafish Lgi1a results in abnormal development, brain defects and a seizure-like behavioral phenotype. Hum Mol Genet 2010; 19:4409-20. [PMID: 20819949 DOI: 10.1093/hmg/ddq364] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Epilepsy is a common disorder, typified by recurrent seizures with underlying neurological disorders or disease. Approximately one-third of patients are unresponsive to currently available therapies. Thus, a deeper understanding of the genetics and etiology of epilepsy is needed to advance the development of new therapies. Previously, treatment of zebrafish with epilepsy-inducing pharmacological agents was shown to result in a seizure-like phenotype, suggesting that fish provide a tractable model to understand the function of epilepsy-predisposing genes. Here, we report the first model of genetically linked epilepsy in zebrafish and provide an initial characterization of the behavioral and neurological phenotypes associated with morpholino (MO) knockdown of leucine-rich, glioma-inactivated 1a (lgi1a) expression. Mutations in the LGI1 gene in humans have been shown to predispose to a subtype of autosomal dominant epilepsy. Low-dose Lgi1a MO knockdown fish (morphants) appear morphologically normal but are sensitized to epilepsy-inducing drugs. High-dose Lgi1a morphants have morphological defects which persist into adult stages that are typified by smaller brains and eyes and abnormalities in tail shape, and display hyperactive swimming behaviors. Increased apoptosis was observed throughout the central nervous system of high-dose morphant fish, accounting for the size reduction of neural tissues. These observations demonstrate that zebrafish can be exploited to dissect the embryonic function(s) of genes known to predispose to seizure-like behavior in humans, and offer potential insight into the relationship between developmental neurobiological abnormalities and seizure.
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Affiliation(s)
- Yong Teng
- MCG Cancer Center, Medical College of Georgia, School of Medicine, 1120 15th Street, Augusta, GA 30912, USA
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Irani SR, Alexander S, Waters P, Kleopa KA, Pettingill P, Zuliani L, Peles E, Buckley C, Lang B, Vincent A. Antibodies to Kv1 potassium channel-complex proteins leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 in limbic encephalitis, Morvan's syndrome and acquired neuromyotonia. ACTA ACUST UNITED AC 2010; 133:2734-48. [PMID: 20663977 PMCID: PMC2929337 DOI: 10.1093/brain/awq213] [Citation(s) in RCA: 916] [Impact Index Per Article: 65.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Antibodies that immunoprecipitate 125I-α-dendrotoxin-labelled voltage-gated potassium channels extracted from mammalian brain tissue have been identified in patients with neuromyotonia, Morvan’s syndrome, limbic encephalitis and a few cases of adult-onset epilepsy. These conditions often improve following immunomodulatory therapies. However, the proportions of the different syndromes, the numbers with associated tumours and the relationships with potassium channel subunit antibody specificities have been unclear. We documented the clinical phenotype and tumour associations in 96 potassium channel antibody positive patients (titres >400 pM). Five had thymomas and one had an endometrial adenocarcinoma. To define the antibody specificities, we looked for binding of serum antibodies and their effects on potassium channel currents using human embryonic kidney cells expressing the potassium channel subunits. Surprisingly, only three of the patients had antibodies directed against the potassium channel subunits. By contrast, we found antibodies to three proteins that are complexed with 125I-α-dendrotoxin-labelled potassium channels in brain extracts: (i) contactin-associated protein-2 that is localized at the juxtaparanodes in myelinated axons; (ii) leucine-rich, glioma inactivated 1 protein that is most strongly expressed in the hippocampus; and (iii) Tag-1/contactin-2 that associates with contactin-associated protein-2. Antibodies to Kv1 subunits were found in three sera, to contactin-associated protein-2 in 19 sera, to leucine-rich, glioma inactivated 1 protein in 55 sera and to contactin-2 in five sera, four of which were also positive for the other antibodies. The remaining 18 sera were negative for potassium channel subunits and associated proteins by the methods employed. Of the 19 patients with contactin-associated protein-antibody-2, 10 had neuromyotonia or Morvan’s syndrome, compared with only 3 of the 55 leucine-rich, glioma inactivated 1 protein-antibody positive patients (P < 0.0001), who predominantly had limbic encephalitis. The responses to immunomodulatory therapies, defined by changes in modified Rankin scores, were good except in the patients with tumours, who all had contactin-associated-2 protein antibodies. This study confirms that the majority of patients with high potassium channel antibodies have limbic encephalitis without tumours. The identification of leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 as the major targets of potassium channel antibodies, and their associations with different clinical features, begins to explain the diversity of these syndromes; furthermore, detection of contactin-associated protein-2 antibodies should help identify the risk of an underlying tumour and a poor prognosis in future patients.
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Affiliation(s)
- Sarosh R Irani
- Neurosciences Group, Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Chabrol E, Navarro V, Provenzano G, Cohen I, Dinocourt C, Rivaud-Péchoux S, Fricker D, Baulac M, Miles R, Leguern E, Baulac S. Electroclinical characterization of epileptic seizures in leucine-rich, glioma-inactivated 1-deficient mice. ACTA ACUST UNITED AC 2010; 133:2749-62. [PMID: 20659958 PMCID: PMC2929330 DOI: 10.1093/brain/awq171] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mutations of the LGI1 (leucine-rich, glioma-inactivated 1) gene underlie autosomal dominant lateral temporal lobe epilepsy, a focal idiopathic inherited epilepsy syndrome. The LGI1 gene encodes a protein secreted by neurons, one of the only non-ion channel genes implicated in idiopathic familial epilepsy. While mutations probably result in a loss of function, the role of LGI1 in the pathophysiology of epilepsy remains unclear. Here we generated a germline knockout mouse for LGI1 and examined spontaneous seizure characteristics, changes in threshold for induced seizures and hippocampal pathology. Frequent spontaneous seizures emerged in homozygous LGI1−/− mice during the second postnatal week. Properties of these spontaneous events were examined in a simultaneous video and intracranial electroencephalographic recording. Their mean duration was 120 ± 12 s, and behavioural correlates consisted of an initial immobility, automatisms, sometimes followed by wild running and tonic and/or clonic movements. Electroencephalographic monitoring indicated that seizures originated earlier in the hippocampus than in the cortex. LGI1−/− mice did not survive beyond postnatal day 20, probably due to seizures and failure to feed. While no major developmental abnormalities were observed, after recurrent seizures we detected neuronal loss, mossy fibre sprouting, astrocyte reactivity and granule cell dispersion in the hippocampus of LGI1−/− mice. In contrast, heterozygous LGI1+/− littermates displayed no spontaneous behavioural epileptic seizures, but auditory stimuli induced seizures at a lower threshold, reflecting the human pathology of sound-triggered seizures in some patients. We conclude that LGI1+/− and LGI1−/− mice may provide useful models for lateral temporal lobe epilepsy, and more generally idiopathic focal epilepsy.
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Affiliation(s)
- Elodie Chabrol
- CRICM UMR_S975, Hôpital de la Pitié-Salpêtrière, Bâtiment Pharmacie, 47 Boulevard de l'hôpital, Paris, France
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