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Ritzau-Jost A, Gsell F, Sell J, Sachs S, Montanaro J, Kirmann T, Maaß S, Irani SR, Werner C, Geis C, Sauer M, Shigemoto R, Hallermann S. LGI1 Autoantibodies Enhance Synaptic Transmission by Presynaptic K v1 Loss and Increased Action Potential Broadening. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2024; 11:e200284. [PMID: 39141878 DOI: 10.1212/nxi.0000000000200284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
BACKGROUND AND OBJECTIVES Autoantibodies against the protein leucine-rich glioma inactivated 1 (LGI1) cause the most common subtype of autoimmune encephalitis with predominant involvement of the limbic system, associated with seizures and memory deficits. LGI1 and its receptor ADAM22 are part of a transsynaptic protein complex that includes several proteins involved in presynaptic neurotransmitter release and postsynaptic glutamate sensing. Autoantibodies against LGI1 increase excitatory synaptic strength, but studies that genetically disrupt the LGI1-ADAM22 complex report a reduction in postsynaptic glutamate receptor-mediated responses. Thus, the mechanisms underlying the increased synaptic strength induced by LGI1 autoantibodies remain elusive, and the contributions of presynaptic molecules to the LGI1-transsynaptic complex remain unclear. We therefore investigated the presynaptic mechanisms that mediate autoantibody-induced synaptic strengthening. METHODS We studied the effects of patient-derived purified polyclonal LGI1 autoantibodies on synaptic structure and function by combining direct patch-clamp recordings from presynaptic boutons and somata of hippocampal neurons with super-resolution light and electron microscopy of hippocampal cultures and brain slices. We also identified the protein domain mediating the presynaptic effect using domain-specific patient-derived monoclonal antibodies. RESULTS LGI1 autoantibodies dose-dependently increased short-term depression during high-frequency transmission, consistent with increased release probability. The increased neurotransmission was not related to presynaptic calcium channels because presynaptic Cav2.1 channel density, calcium current amplitude, and calcium channel gating were unaffected by LGI1 autoantibodies. By contrast, application of LGI1 autoantibodies homogeneously reduced Kv1.1 and Kv1.2 channel density on the surface of presynaptic boutons. Direct presynaptic patch-clamp recordings revealed that LGI1 autoantibodies cause a pronounced broadening of the presynaptic action potential. Domain-specific effects of LGI1 autoantibodies were analyzed at the neuronal soma. Somatic action potential broadening was induced by polyclonal LGI1 autoantibodies and patient-derived monoclonal autoantibodies targeting the epitempin domain, but not the leucin-rich repeat domain. DISCUSSION Our results indicate that LGI1 autoantibodies reduce the density of both Kv1.1 and Kv1.2 on presynaptic boutons, without actions on calcium channel density or function, thereby broadening the presynaptic action potential and increasing neurotransmitter release. This study provides a molecular explanation for the neuronal hyperactivity observed in patients with LGI1 autoantibodies.
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Affiliation(s)
- Andreas Ritzau-Jost
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Felix Gsell
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Josefine Sell
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Stefan Sachs
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Jacqueline Montanaro
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Toni Kirmann
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Sebastian Maaß
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Sarosh R Irani
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Christian Werner
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Christian Geis
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Markus Sauer
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Ryuichi Shigemoto
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
| | - Stefan Hallermann
- From the Carl-Ludwig-Institute of Physiology (A.R.-J., F.G., T.K., S.M., S.H.), Faculty of Medicine, Leipzig University; Section Translational Neuroimmunology (J.S., C.G.), Department of Neurology, Jena University Hospital; Department of Biotechnology and Biophysics (S.S., C.W., M.S.), University of Würzburg, Biocenter, Germany; Institute of Science and Technology Austria (ISTA) (J.M., R.S.), Klosterneuburg, Austria; Oxford Autoimmune Neurology Group (S.R.I.), Nuffield Department of Clinical Neurosciences, University of Oxford, ; Department of Neurology (S.R.I.), John Radcliffe Hospital, Oxford University Hospitals, United Kingdom; and Departments of Neurology and Neurosciences (S.R.I.), Mayo Clinic Jacksonville, FL
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Wang C, Guo X, Long D, Li Y, Yuan C, Ni G, Zhang H, Li X, Yin S, Peng X, Huang W, Chen S, Liu Y, Chen Z. Familial mesial temporal lobe epilepsy phenotype is associated with novel LGI1 variants: A report of two families. Seizure 2024; 120:180-188. [PMID: 39029408 DOI: 10.1016/j.seizure.2024.07.005] [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: 03/12/2024] [Revised: 07/02/2024] [Accepted: 07/02/2024] [Indexed: 07/21/2024] Open
Abstract
OBJECTIVE To expand the clinical phenotype and mutation spectrum of familial mesial temporal lobe epilepsy (FMTLE) and provide a new perspective for exploring the pathological mechanisms of epilepsy caused by leucine-rich glioma inactivated 1 (LGI1) variants. METHODS We reported clinical data from two families with FMTLE and screened patients for variants in the LGI1 gene using Whole-exome sequencing and Sanger sequencing. The clinical features of FMTLE were analysed. The pathogenicity of the causative loci was assessed according to the American College of Medical Genetics and Genomics guidelines, and potential pathogenic mechanisms were predicted through multiple bioinformatics and molecular dynamics software. RESULTS We identified two novel LGI1 truncating variants within two large families with FMTLE: LGI1 (c.1174C>T, p.Q392X) and LGI1 (c.703C>T, p.Q235X). Compared to previous reports, we found that focal to bilateral tonic-clonic seizures are a common type of seizure in FMTLE. The clinical phenotypes of patients with FMTLE caused by LGI1 variants were relatively mild, and all patients responded well to valproic acid. Bioinformatics analyses and molecular dynamics simulations showed that protein structure and interactions were considerably weakened or damaged as a result of both variants. CONCLUSION This study presents the first report identifying LGI1 as a potential novel pathogenic gene within FMTLE families, thereby broadening the mutation spectrum associated with FMTLE. The findings of this study offer novel insights and avenues for understanding the intricate molecular mechanisms underlying LGI1 variants and their correlations with patient phenotypes. This study proposes the possibility of familial focal epilepsy syndromes overlapping.
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Affiliation(s)
- Chengzhe Wang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Xintong Guo
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Dingju Long
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Yinchao Li
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Cai Yuan
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, PR China
| | - Guanzhong Ni
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Heyu Zhang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Xi Li
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China; Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Sijing Yin
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China; Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Xinxin Peng
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China; Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Wenyao Huang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Siqing Chen
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China
| | - Yue Liu
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China; Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, Shenzhen 518107, PR China
| | - Ziyi Chen
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou 510080, PR China.
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Extrémet J, Ramirez-Franco J, Fronzaroli-Molinieres L, Boumedine-Guignon N, Ankri N, El Far O, Garrido JJ, Debanne D, Russier M. Rescue of Normal Excitability in LGI1-Deficient Epileptic Neurons. J Neurosci 2023; 43:8596-8606. [PMID: 37863654 PMCID: PMC10727174 DOI: 10.1523/jneurosci.0701-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/08/2023] [Accepted: 10/14/2023] [Indexed: 10/22/2023] Open
Abstract
Leucine-rich glioma inactivated 1 (LGI1) is a glycoprotein secreted by neurons, the deletion of which leads to autosomal dominant lateral temporal lobe epilepsy. We previously showed that LGI1 deficiency in a mouse model (i.e., knock-out for LGI1 or KO-Lgi1) decreased Kv1.1 channel density at the axon initial segment (AIS) and at presynaptic terminals, thus enhancing both intrinsic excitability and glutamate release. However, it is not known whether normal excitability can be restored in epileptic neurons. Here, we show that the selective expression of LGI1 in KO-Lgi1 neurons from mice of both sexes, using single-cell electroporation, reduces intrinsic excitability and restores both the Kv1.1-mediated D-type current and Kv1.1 channels at the AIS. In addition, we show that the homeostatic-like shortening of the AIS length observed in KO-Lgi1 neurons is prevented in neurons electroporated with the Lgi1 gene. Furthermore, we reveal a spatial gradient of intrinsic excitability that is centered on the electroporated neuron. We conclude that expression of LGI1 restores normal excitability through functional Kv1 channels at the AIS.SIGNIFICANCE STATEMENT The lack of leucine-rich glioma inactivated 1 (LGI1) protein induces severe epileptic seizures that leads to death. Enhanced intrinsic and synaptic excitation in KO-Lgi1 mice is because of the decrease in Kv1.1 channels in CA3 neurons. However, the conditions to restore normal excitability profile in epileptic neurons remain to be defined. We show here that the expression of LGI1 in KO-Lgi1 neurons in single neurons reduces intrinsic excitability, and restores both the Kv1.1-mediated D-type current and Kv1.1 channels at the axon initial segment (AIS). Furthermore, the homeostatic shortening of the AIS length observed in KO-Lgi1 neurons is prevented in neurons in which the Lgi1 gene has been rescued. We conclude that LGI1 constitutes a critical factor to restore normal excitability in epileptic neurons.
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Affiliation(s)
- Johanna Extrémet
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Jorge Ramirez-Franco
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Laure Fronzaroli-Molinieres
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Norah Boumedine-Guignon
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Norbert Ankri
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Oussama El Far
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Juan José Garrido
- Cajal Institute, Consejo Superior de Investigaciones Cientificas, Madrid, 28002, Spain
| | - Dominique Debanne
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Michaël Russier
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
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Marafi D, Kozar N, Duan R, Bradley S, Yokochi K, Al Mutairi F, Saadi NW, Whalen S, Brunet T, Kotzaeridou U, Choukair D, Keren B, Nava C, Kato M, Arai H, Froukh T, Faqeih EA, AlAsmari AM, Saleh MM, Pinto e Vairo F, Pichurin PN, Klee EW, Schmitz CT, Grochowski CM, Mitani T, Herman I, Calame DG, Fatih JM, Du H, Coban-Akdemir Z, Pehlivan D, Jhangiani SN, Gibbs RA, Miyatake S, Matsumoto N, Wagstaff LJ, Posey JE, Lupski JR, Meijer D, Wagner M. A reverse genetics and genomics approach to gene paralog function and disease: Myokymia and the juxtaparanode. Am J Hum Genet 2022; 109:1713-1723. [PMID: 35948005 PMCID: PMC9502070 DOI: 10.1016/j.ajhg.2022.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
The leucine-rich glioma-inactivated (LGI) family consists of four highly conserved paralogous genes, LGI1-4, that are highly expressed in mammalian central and/or peripheral nervous systems. LGI1 antibodies are detected in subjects with autoimmune limbic encephalitis and peripheral nerve hyperexcitability syndromes (PNHSs) such as Isaacs and Morvan syndromes. Pathogenic variations of LGI1 and LGI4 are associated with neurological disorders as disease traits including familial temporal lobe epilepsy and neurogenic arthrogryposis multiplex congenita 1 with myelin defects, respectively. No human disease has been reported associated with either LGI2 or LGI3. We implemented exome sequencing and family-based genomics to identify individuals with deleterious variants in LGI3 and utilized GeneMatcher to connect practitioners and researchers worldwide to investigate the clinical and electrophysiological phenotype in affected subjects. We also generated Lgi3-null mice and performed peripheral nerve dissection and immunohistochemistry to examine the juxtaparanode LGI3 microarchitecture. As a result, we identified 16 individuals from eight unrelated families with loss-of-function (LoF) bi-allelic variants in LGI3. Deep phenotypic characterization showed LGI3 LoF causes a potentially clinically recognizable PNHS trait characterized by global developmental delay, intellectual disability, distal deformities with diminished reflexes, visible facial myokymia, and distinctive electromyographic features suggestive of motor nerve instability. Lgi3-null mice showed reduced and mis-localized Kv1 channel complexes in myelinated peripheral axons. Our data demonstrate bi-allelic LoF variants in LGI3 cause a clinically distinguishable disease trait of PNHS, most likely caused by disturbed Kv1 channel distribution in the absence of LGI3.
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Affiliation(s)
- Dana Marafi
- Department of Pediatrics, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nina Kozar
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Ruizhi Duan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stephen Bradley
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Kenji Yokochi
- Department of Pediatrics, Toyohashi Municipal Hospital, Toyohashi, Aichi 441-8570, Japan,Department of Pediatrics, Seirei Mikatahara General Hospital, Shizuoka 433-8558, Japan
| | - Fuad Al Mutairi
- Genetics and Precision Medicine Department, King Abdullah Specialized Children’s Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, P.O. Box 22490, Riyadh 11426, Kingdom of Saudi Arabia,King Abdullah International Research Center, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Nebal Waill Saadi
- College of Medicine, University of Baghdad, Baghdad 10001, Iraq,Children Welfare Teaching Hospital, Medical City Complex, Baghdad 10001, Iraq
| | - Sandra Whalen
- UF de Génétique Clinique et Centre de Reference Anomalies du Développement et Syndromes Malformatifs, APHP, Sorbonne Université, Hôpital Trousseau, 75005 Paris, France
| | - Theresa Brunet
- Institute of Human Genetics, Faculty of Medicine, Technical University Munich, Munich, Germany,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Urania Kotzaeridou
- Division of Child Neurology and Inherited Metabolic Diseases, Centre for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Daniela Choukair
- Division of Pediatric Endocrinology, Centre for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Boris Keren
- Département de Génétique, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris 75013, France
| | - Caroline Nava
- Département de Génétique, Hôpital Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris 75013, France
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo 142-8666, Japan
| | - Hiroshi Arai
- Department of Pediatric Neurology, Bobath Memorial Hospital, Osaka 536-0023, Japan
| | - Tawfiq Froukh
- Department of Biotechnology and Genetic Engineering, Philadelphia University, Amman, Jordan
| | - Eissa Ali Faqeih
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Ali M. AlAsmari
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Mohammed M. Saleh
- Section of Medical Genetics, King Fahad Medical City, Children’s Specialist Hospital, Riyadh, Saudi Arabia
| | - Filippo Pinto e Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | | | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA,Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | | | | | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Isabella Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Daniel G. Calame
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Jawid M. Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA
| | - Shalini N. Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard A. Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan,Clinical Genetics Department, Yokohama City University Hospital, Yokohama, Kanagawa 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan
| | - Laura J. Wagstaff
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, UK
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Texas Children’s Hospital, Houston, TX 77030, USA,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA,Corresponding author
| | - Dies Meijer
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Matias Wagner
- Institute for Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany,Institute of Human Genetics, Technical University Munich, Munich, Germany
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5
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Zhou P, Meng H, Liang X, Lei X, Zhang J, Bian W, He N, Lin Z, Song X, Zhu W, Hu B, Li B, Yan L, Tang B, Su T, Liu H, Mao Y, Zhai Q, Yi Y. ADGRV1 Variants in Febrile Seizures/Epilepsy With Antecedent Febrile Seizures and Their Associations With Audio-Visual Abnormalities. Front Mol Neurosci 2022; 15:864074. [PMID: 35813073 PMCID: PMC9262510 DOI: 10.3389/fnmol.2022.864074] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/25/2022] [Indexed: 12/14/2022] Open
Abstract
Objective ADGRV1 gene encodes adhesion G protein-coupled receptor-V1 that is involved in synaptic function. ADGRV1 mutations are associated with audio-visual disorders. Although previous experimental studies suggested that ADGRV1 variants were associated with epilepsy, clinical evidence is limited and the phenotype spectrum is to be defined. Methods Trio-based targeting sequencing was performed in a cohort of 101 cases with febrile seizure (FS) and epilepsy with antecedent FS. Protein modeling was used to assess the damaging effects of variants. The genotype-phenotype correlations of the ADGRV1 variants in epilepsy and audio-visual disorders were analyzed. Results ADGRV1 variants were identified in nine unrelated cases (8.91%), including two heterozygous frameshift variants, six heterozygous missense variants, and a pair of compound heterozygous variants. These variants presented a statistically higher frequency in this cohort than that in control populations. Most missense variants were located at CalX-β motifs and changed the hydrogen bonds. These variants were inherited from the asymptomatic parents, indicating an incomplete penetrance. We also identified SCN1A variants in 25 unrelated cases (24.75%) and SCN9A variants in 3 unrelated cases (2.97%) in this cohort. Contrary to SCN1A variant-associated epilepsy that revealed seizure was aggravated by sodium channel blockers, ADGRV1 variants were associated with mild epilepsy with favorable responses to antiepileptic drugs. The patients denied problems with audio-visual-vestibular abilities in daily life. However, audio-visual tests revealed auditory and visual impairment in the patient with compound heterozygous variants, auditory or vestibular impairment in the patients with heterozygous frameshift, or hydrogen-bond changed missense variants but no abnormalities in the patients with missense variants without hydrogen-bond changes. Previously reported ADGRV1 variants that were associated with audio-visual disorders were mostly biallelic/destructive variants, which were significantly more frequent in the severe phenotype of audio-visual disorders (Usher syndrome 2) than in other mild phenotypes. In contrast, the variants identified in epilepsy were monoallelic, missense mainly located at CalX-β, or affected isoforms VLGR1b/1c. Significance ADGRV1 is potentially associated with FS-related epilepsy as a susceptibility gene. The genotype, submolecular implication, isoforms, and damaging severity of the variants explained the phenotypical variations. ADGRV1 variant-associated FS/epilepsy presented favorable responses to antiepileptic drugs, implying a clinical significance.
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Affiliation(s)
- Peng Zhou
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Heng Meng
- Department of Neurology, The First Affiliated Hospital of Jinan University, Clinical Neuroscience Institute of Jinan University, Guangzhou, China
| | - Xiaoyu Liang
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Xiaoyun Lei
- Department of Neurology, The First Affiliated Hospital of Jinan University, Clinical Neuroscience Institute of Jinan University, Guangzhou, China
| | - Jingwen Zhang
- Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wenjun Bian
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Na He
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Zhijian Lin
- Department of Neurology, Affiliated Hospital of Putian University, Putian, China
| | - Xingwang Song
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Weiwen Zhu
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Bin Hu
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Bingmei Li
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Limin Yan
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Bin Tang
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Tao Su
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | | | | | - Qiongxiang Zhai
- Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
- *Correspondence: Qiongxiang Zhai
| | - Yonghong Yi
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Department of Neurology, Institute of Neuroscience, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- Yonghong Yi
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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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Rabie EA, Sayed ISM, Amr K, Ahmed HA, Mostafa MI, Hassib NF, El-Sayed H, Zada SK, El-Kamah G. Confirmation of a Phenotypic Entity for TSPEAR Variants in Egyptian Ectodermal Dysplasia Patients and Role of Ethnicity. Genes (Basel) 2022; 13:1056. [PMID: 35741818 PMCID: PMC9222913 DOI: 10.3390/genes13061056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 02/01/2023] Open
Abstract
Ectodermal dysplasia (ED) are hereditary disorders characterized by the disturbance of the ectodermal development of at least two of four ectodermal tissues: teeth, hair, nails and sweat glands. Clinical classification of ED is challenged by overlapping features, variable expressivity, and low number of patients, hindering full phenotypic spectrum identification. Disease-causing variants in elements of major developmental pathways, e.g., Ectodysplasin/NFκB, Wnt, and Tp63 pathways, have been identified in fewer than half of ED phenotypes. Whole-exome sequencing (WES) was performed for ten Egyptian ED patients presenting with tooth agenesis, normal sweating, scalp hypotrichosis, and sharing characteristic facial features. WES was followed by in silico analysis of the effects of novel detected genetic variants on mRNA and protein structure. The study identified four novel rare pathogenic and likely pathogenic TSPEAR variants, a gene which was recently found to be involved in ectodermal organogenesis. A novel in-frame deletion recurred in eight patients from six unrelated families. Comparing our cohort to previously reported TSPEAR cohorts highlighted the influence of ethnicity on TSPEAR phenotypic affection. Our study expands the clinical and mutational spectrum of the growing TSPEAR associated phenotypes, and pinpoints the influence of WES and in silico tools on identification of rare disease-causing variants.
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Affiliation(s)
- Eman A. Rabie
- Medical Molecular Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt;
- Biology Department, School of Sciences and Engineering, The American University in Cairo (AUC), Cairo 11835, Egypt;
| | - Inas S. M. Sayed
- Orodental Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt; (I.S.M.S.); (M.I.M.); (N.F.H.)
| | - Khalda Amr
- Medical Molecular Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt;
| | - Hoda A. Ahmed
- Medical Molecular Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt;
| | - Mostafa I. Mostafa
- Orodental Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt; (I.S.M.S.); (M.I.M.); (N.F.H.)
| | - Nehal F. Hassib
- Orodental Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt; (I.S.M.S.); (M.I.M.); (N.F.H.)
| | - Heba El-Sayed
- Clinical Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt;
| | - Suher K. Zada
- Biology Department, School of Sciences and Engineering, The American University in Cairo (AUC), Cairo 11835, Egypt;
| | - Ghada El-Kamah
- Clinical Genetics Department, Human Genetics & Genome Research Division (HGGR), National Research Centre (NRC), Cairo 12622, Egypt;
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8
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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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9
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Haber M, Burgsdorf I, Handley KM, Rubin-Blum M, Steindler L. Genomic Insights Into the Lifestyles of Thaumarchaeota Inside Sponges. Front Microbiol 2021; 11:622824. [PMID: 33537022 PMCID: PMC7848895 DOI: 10.3389/fmicb.2020.622824] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/14/2020] [Indexed: 11/28/2022] Open
Abstract
Sponges are among the oldest metazoans and their success is partly due to their abundant and diverse microbial symbionts. They are one of the few animals that have Thaumarchaeota symbionts. Here we compare genomes of 11 Thaumarchaeota sponge symbionts, including three new genomes, to free-living ones. Like their free-living counterparts, sponge-associated Thaumarchaeota can oxidize ammonia, fix carbon, and produce several vitamins. Adaptions to life inside the sponge host include enrichment in transposases, toxin-antitoxin systems and restriction modifications systems, enrichments previously reported also from bacterial sponge symbionts. Most thaumarchaeal sponge symbionts lost the ability to synthesize rhamnose, which likely alters their cell surface and allows them to evade digestion by the host. All but one archaeal sponge symbiont encoded a high-affinity, branched-chain amino acid transporter system that was absent from the analyzed free-living thaumarchaeota suggesting a mixotrophic lifestyle for the sponge symbionts. Most of the other unique features found in sponge-associated Thaumarchaeota, were limited to only a few specific symbionts. These features included the presence of exopolyphosphatases and a glycine cleavage system found in the novel genomes. Thaumarchaeota have thus likely highly specific interactions with their sponge host, which is supported by the limited number of host sponge species to which each of these symbionts is restricted.
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Affiliation(s)
- Markus Haber
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, České Budějovice, Czechia
| | - Ilia Burgsdorf
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Kim M. Handley
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Maxim Rubin-Blum
- Israel Oceanographic and Limnological Research Institute, Haifa, Israel
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
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10
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Gawel K, Langlois M, Martins T, van der Ent W, Tiraboschi E, Jacmin M, Crawford AD, Esguerra CV. Seizing the moment: Zebrafish epilepsy models. Neurosci Biobehav Rev 2020; 116:1-20. [PMID: 32544542 DOI: 10.1016/j.neubiorev.2020.06.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | | | - Teresa Martins
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Ettore Tiraboschi
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Neurophysics Group, Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, Building 14, 38068, Rovereto, TN, Italy
| | - Maxime Jacmin
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Alexander D Crawford
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg; Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
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11
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Dunn PJ, Maher BH, Albury CL, Stuart S, Sutherland HG, Maksemous N, Benton MC, Smith RA, Haupt LM, Griffiths LR. Tiered analysis of whole-exome sequencing for epilepsy diagnosis. Mol Genet Genomics 2020; 295:751-763. [DOI: 10.1007/s00438-020-01657-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/19/2020] [Indexed: 12/11/2022]
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12
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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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13
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Yamagata A, Fukai S. Structural insights into leucine-rich repeat-containing synaptic cleft molecules. Curr Opin Struct Biol 2019; 54:68-77. [PMID: 30784960 DOI: 10.1016/j.sbi.2019.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 11/28/2018] [Accepted: 01/07/2019] [Indexed: 02/04/2023]
Abstract
Synapses are cell adhesion structures specialized for signal transmission between neurons. At the synapse, presynaptic and postsynaptic terminals of neurons are functionally connected but spatially separated and form a cleft. Membrane receptor-like cell adhesion molecules and secreted proteins in the synaptic cleft (synaptic cleft molecules) can mediate structural and functional linkages between the presynaptic and postsynaptic terminals for neural development or activity. A leucine-rich repeat (LRR) has been known as a typical structural motif for protein-protein interactions and plays important roles in intermolecular interactions mediated by synaptic cleft molecules. In this review, we summarize structural insights into LRR-containing synaptic cleft molecules from recent structural studies and discuss how they are linked to their downstream events.
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Affiliation(s)
- Atsushi Yamagata
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0032, Japan; Synchrotron Radiation Research Organization, The University of Tokyo, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan.
| | - Shuya Fukai
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0032, Japan; Synchrotron Radiation Research Organization, The University of Tokyo, Tokyo 113-0032, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan.
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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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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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Pei J, Kinch LN, Grishin NV. FlyXCDB—A Resource for Drosophila Cell Surface and Secreted Proteins and Their Extracellular Domains. J Mol Biol 2018; 430:3353-3411. [DOI: 10.1016/j.jmb.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/31/2018] [Accepted: 06/02/2018] [Indexed: 02/06/2023]
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Structural basis of epilepsy-related ligand-receptor complex LGI1-ADAM22. Nat Commun 2018; 9:1546. [PMID: 29670100 PMCID: PMC5906670 DOI: 10.1038/s41467-018-03947-w] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 03/23/2018] [Indexed: 01/17/2023] Open
Abstract
Epilepsy is a common brain disorder throughout history. Epilepsy-related ligand–receptor complex, LGI1–ADAM22, regulates synaptic transmission and has emerged as a determinant of brain excitability, as their mutations and acquired LGI1 autoantibodies cause epileptic disorders in human. Here, we report the crystal structure of human LGI1–ADAM22 complex, revealing a 2:2 heterotetrameric assembly. The hydrophobic pocket of the C-terminal epitempin-repeat (EPTP) domain of LGI1 binds to the metalloprotease-like domain of ADAM22. The N-terminal leucine-rich repeat and EPTP domains of LGI1 mediate the intermolecular LGI1–LGI1 interaction. A pathogenic R474Q mutation of LGI1, which does not exceptionally affect either the secretion or the ADAM22 binding, is located in the LGI1–LGI1 interface and disrupts the higher-order assembly of the LGI1–ADAM22 complex in vitro and in a mouse model for familial epilepsy. These studies support the notion that the LGI1–ADAM22 complex functions as the trans-synaptic machinery for precise synaptic transmission. LGI1 is an epilepsy-related gene that encodes a secreted neuronal protein. Here the authors present the crystal structure of LGI1 bound to its receptor ADAM22, which provides structural insights into epilepsy-causing LGI1 mutations and might facilitate the development of novel anti-epilepsy drugs.
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Green CM, Novikova O, Belfort M. The dynamic intein landscape of eukaryotes. Mob DNA 2018; 9:4. [PMID: 29416568 PMCID: PMC5784728 DOI: 10.1186/s13100-018-0111-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/18/2018] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Inteins are mobile, self-splicing sequences that interrupt proteins and occur across all three domains of life. Scrutiny of the intein landscape in prokaryotes led to the hypothesis that some inteins are functionally important. Our focus shifts to eukaryotic inteins to assess their diversity, distribution, and dissemination, with the aim to comprehensively evaluate the eukaryotic intein landscape, understand intein maintenance, and dissect evolutionary relationships. RESULTS This bioinformatics study reveals that eukaryotic inteins are scarce, but present in nuclear genomes of fungi, chloroplast genomes of algae, and within some eukaryotic viruses. There is a preponderance of inteins in several fungal pathogens of humans and plants. Inteins are pervasive in certain proteins, including the nuclear RNA splicing factor, Prp8, and the chloroplast DNA helicase, DnaB. We find that eukaryotic inteins frequently localize to unstructured loops of the host protein, often at highly conserved sites. More broadly, a sequence similarity network analysis of all eukaryotic inteins uncovered several routes of intein mobility. Some eukaryotic inteins appear to have been acquired through horizontal transfer with dsDNA viruses, yet other inteins are spread through intragenomic transfer. Remarkably, endosymbiosis can explain patterns of DnaB intein inheritance across several algal phyla, a novel mechanism for intein acquisition and distribution. CONCLUSIONS Overall, an intriguing picture emerges for how the eukaryotic intein landscape arose, with many evolutionary forces having contributed to its current state. Our collective results provide a framework for exploring inteins as novel regulatory elements and innovative drug targets.
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Affiliation(s)
- Cathleen M. Green
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Olga Novikova
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
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De Luca C, Papa M. Matrix Metalloproteinases, Neural Extracellular Matrix, and Central Nervous System Pathology. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 148:167-202. [PMID: 28662822 DOI: 10.1016/bs.pmbts.2017.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The functionality and stability of the central nervous system (CNS) pabulum, called neural extracellular matrix (nECM), is paramount for the maintenance of a healthy network. The loosening or the damage of the scaffold disrupts synaptic transmission with the consequent imbalance of the neurotransmitters, reactive cells invasion, astrocytosis, new matrix deposition, digestion of the previous structure and ultimately, maladaptive plasticity with the loss of neuronal viability. nECM is constantly affected by CNS disorders, particularly in chronic modifying such as neurodegenerative disease, or in acute/subacute with chronic sequelae, like cerebrovascular and inflammatory pathology. Matrix metalloproteinases (MMPs) are the main interfering agent of nECM, guiding the balance of degradation and new deposition of proteins such as proteoglycans and glycoproteins, or glycosaminoglycans, such as hyaluronic acid. Activation of these enzymes is modulated by their physiologic inhibitors, the tissue inhibitors of MMPs or via other proteases inhibitors, as well as genetic or epigenetic up- or downregulation through molecular interaction or receptor activation. The appropriate understanding of the pathways underlying nECM modifications in CNS pathology is probably one of the pivotal future directions to identify the healthy brain network and subsequently design new therapies to interfere with the progression of the CNS disease and eventually find appropriate therapies.
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Affiliation(s)
- Ciro De Luca
- Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Michele Papa
- Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", Naples, Italy; SYSBIO, Centre for Systems Biology, University of Milano-Bicocca, Milano, Italy.
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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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Screening LGI1 in a cohort of 26 lateral temporal lobe epilepsy patients with auditory aura from Turkey detects a novel de novo mutation. Epilepsy Res 2016; 120:73-8. [DOI: 10.1016/j.eplepsyres.2015.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 11/02/2015] [Accepted: 12/09/2015] [Indexed: 11/24/2022]
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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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Pakozdy A, Patzl M, Zimmermann L, Jokinen TS, Glantschnigg U, Kelemen A, Hasegawa D. LGI Proteins and Epilepsy in Human and Animals. J Vet Intern Med 2015; 29:997-1005. [PMID: 26032921 PMCID: PMC4895363 DOI: 10.1111/jvim.12610] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/23/2015] [Accepted: 04/11/2015] [Indexed: 12/16/2022] Open
Abstract
Leucine‐rich glioma‐inactivated (LGI) protein was first thought to have a suppressor effect in the formation of some cancers. Developments in physiology and medicine made it possible to characterize the function of the LGI protein family and its crucial role in different conditions more precisely. These proteins play an important role in synaptic transmission, and dysfunction may cause hyperexcitability. Genetic mutation of LGI1was confirmed to be the cause of autosomal dominant lateral temporal lobe epilepsy in humans. The LGI2 mutation was identified in benign familial juvenile epilepsy in Lagotto Romagnolo (LR) dogs. Cats with familial spontaneous temporal lobe epilepsy have been reported, and the etiology might be associated with LGI protein family dysfunction. In addition, an autoimmune reaction against LGI1 was detected in humans and cats with limbic encephalitis. These advances prompted a review of LGI protein function and its role in different seizure disorders.
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Affiliation(s)
- A Pakozdy
- University Clinic of Small Animals, University of Veterinary Medicine, Vienna, Austria
| | - M Patzl
- Institute of Immunology, University of Veterinary Medicine, Vienna, Austria
| | - L Zimmermann
- Unit of Physiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - T S Jokinen
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - U Glantschnigg
- University Clinic of Small Animals, University of Veterinary Medicine, Vienna, Austria
| | - A Kelemen
- Epilepsy Center, National Institute of Clinical Neurosciences, Budapest, Hungary
| | - D Hasegawa
- Department of Clinical Veterinary Medicine, Nippon Veterinary and Life Science University, Musashinoshi, Tokyo, Japan
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Dazzo E, Santulli L, Posar A, Fattouch J, Conti S, Lodén-van Straaten M, Mijalkovic J, De Bortoli M, Rosa M, Millino C, Pacchioni B, Di Bonaventura C, Giallonardo AT, Striano S, Striano P, Parmeggiani A, Nobile C. Autosomal dominant lateral temporal epilepsy (ADLTE): novel structural and single-nucleotide LGI1 mutations in families with predominant visual auras. Epilepsy Res 2014; 110:132-8. [PMID: 25616465 DOI: 10.1016/j.eplepsyres.2014.12.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/11/2014] [Accepted: 12/01/2014] [Indexed: 01/05/2023]
Abstract
PURPOSE Autosomal dominant lateral temporal epilepsy (ADLTE) is a genetic focal epilepsy syndrome characterized by prominent auditory or aphasic symptoms. Mutations in LGI1 account for less than 50% of ADLTE families. We assessed the impact of LGI1 microrearrangements in a collection of ADLTE families and sporadic lateral temporal epilepsy (LTE) patients, and investigated novel ADLTE and LTE patients. METHODS Twenty-four ADLTE families and 140 sporadic LTE patients with no evidence of point mutations in LGI1 were screened for copy number alterations using multiplex ligation-dependent probe amplification (MLPA). Newly ascertained familial and sporadic LTE patients were clinically investigated, and interictal EEG and MRI findings were obtained; probands were tested for LGI1 mutations by direct exon sequencing or denaturing high performance liquid chromatography. RESULTS We identified a novel microdeletion spanning LGI1 exon 2 in a family with two affected members, both presenting focal seizures with visual symptoms. Also, we identified a novel LGI1 missense mutation (c.1118T > C; p.L373S) in a newly ascertained family with focal seizures with prominent visual auras, and another missense mutation (c.856T > C; p.C286R) in a sporadic patient with auditory seizures. CONCLUSIONS We describe two novel ADLTE families with predominant visual auras segregating pathogenic LGI1 mutations. These findings support the notion that, in addition to auditory symptoms, other types of auras can be found in patients carrying LGI1 mutations. The identification of a novel microdeletion in LGI1, the second so far identified, suggests that LGI1 microrearrangements may not be exceptional.
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Affiliation(s)
- Emanuela Dazzo
- CNR-Neuroscience Institute, Section of Padua, Padova, Italy
| | - Lia Santulli
- Department of Neurological Sciences, Federico II University, Napoli, Italy
| | - Annio Posar
- IRCCS-Neurological Sciences, Bellaria Hospital, Bologna, Italy
| | - Jinane Fattouch
- Department of Neurological Sciences, La Sapienza University, Roma, Italy
| | - Sara Conti
- IRCCS-Neurological Sciences, Bellaria Hospital, Bologna, Italy
| | | | | | | | - Maurizio Rosa
- Department of Biology, University of Padova, Padova, Italy
| | | | | | | | | | - Salvatore Striano
- Department of Neurological Sciences, Federico II University, Napoli, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Institute "G. Gaslini", University of Genova, Genova, Italy
| | | | - Carlo Nobile
- CNR-Neuroscience Institute, Section of Padua, Padova, Italy.
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A novel mutation of the USH2C (GPR98) gene in an Iranian family with Usher syndrome type II. J Genet 2014; 93:837-41. [DOI: 10.1007/s12041-014-0443-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Zhu YH, Liu H, Zhang LY, Zeng T, Song Y, Qin YR, Li L, Liu L, Li J, Zhang B, Guan XY. Downregulation of LGI1 promotes tumor metastasis in esophageal squamous cell carcinoma. Carcinogenesis 2014; 35:1154-61. [PMID: 24510112 DOI: 10.1093/carcin/bgu040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Here, we report the characterization of a candidate tumor suppressor gene leucine-rich glioma inactivated 1 (LGI1) in human esophageal squamous cell carcinoma (ESCC). Downregulation of LGI1 has been detected in approximately 50% of primary ESCCs, which was significantly associated with advanced clinical stage (P < 0.001), lymph node metastasis (P < 0.001), tumor invasion (P = 0.009) and poor disease-specific survival (P < 0.001). Functional studies found that LGI1 could inhibit cell growth, clonogenicity, cell motility and tumor formation in nude mice. Mechanistic investigations suggested that LGI1 acted through extracellular signal-regulated kinase (ERK1/2) signaling to downregulate matrix metalloproteinase (MMP)-3 expression and subsequently suppressed tumor metastasis. Taken together, our study revealed that LGI1 plays an important tumor suppressive role in the development and progression of ESCC, with possible application in clinics as a biomarker and a potential new therapeutic target.
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Affiliation(s)
- Ying-Hui Zhu
- State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
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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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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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Regulated vesicular trafficking of specific PCDH15 and VLGR1 variants in auditory hair cells. J Neurosci 2013; 32:13841-59. [PMID: 23035094 DOI: 10.1523/jneurosci.1242-12.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Usher syndrome is a genetically heterogeneous disorder characterized by hearing and balance dysfunction and progressive retinitis pigmentosa. Mouse models carrying mutations for the nine Usher-associated genes have splayed stereocilia, and some show delayed maturation of ribbon synapses suggesting these proteins may play different roles in terminal differentiation of auditory hair cells. The presence of the Usher proteins at the basal and apical aspects of the neurosensory epithelia suggests the existence of regulated trafficking through specific transport proteins and routes. Immature mouse cochleae and UB/OC-1 cells were used in this work to address whether specific variants of PCDH15 and VLGR1 are being selectively transported to opposite poles of the hair cells. Confocal colocalization studies between apical and basal vesicular markers and the different PCDH15 and VLGR1 variants along with sucrose density gradients and the use of vesicle trafficking inhibitors show the existence of Usher protein complexes in at least two vesicular subpools. The apically trafficked pool colocalized with the early endosomal vesicle marker, rab5, while the basally trafficked pool associated with membrane microdomains and SNAP25. Moreover, coimmunoprecipitation experiments between SNAP25 and VLGR1 show a physical interaction of these two proteins in organ of Corti and brain. Collectively, these findings establish the existence of a differential vesicular trafficking mechanism for specific Usher protein variants in mouse cochlear hair cells, with the apical variants playing a potential role in endosomal recycling and stereocilia development/maintenance, and the basolateral variants involved in vesicle docking and/or fusion through SNAP25-mediated interactions.
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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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Affiliation(s)
- Ortrud K Steinlein
- School of Medicine, Ludwig-Maximilians University of Munich, Munich, Germany.
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Delmaghani S, Aghaie A, Michalski N, Bonnet C, Weil D, Petit C. Defect in the gene encoding the EAR/EPTP domain-containing protein TSPEAR causes DFNB98 profound deafness. Hum Mol Genet 2012; 21:3835-44. [PMID: 22678063 DOI: 10.1093/hmg/dds212] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We report a consanguineous Iranian family affected by congenital profound sensorineural deafness segregating in an autosomal recessive mode. Auditory tests implicated at least a cochlear defect in these patients. We mapped the deafness, autosomal recessive (DFNB) locus involved by linkage analysis to a 4.8 Mb region at chromosome 21q22.3-qter. Exclusion of the DFNB8/10 gene TMPRSS3, located in this chromosomal interval, led us to identify a new deafness locus, DFNB98. Whole exome sequencing allowed us to identify a homozygous frame-shifting mutation (c.1726G>T+c.1728delC) in the gene TSPEAR (thrombospondin-type laminin G domain and EAR repeats). This truncating mutation (p.V576LfsX37) impeded the secretion of the encoded protein by cells transfected with the mutated gene. Alternative splicing of TSPEAR transcripts predict two protein isoforms, 522 and 669 amino acids in length, both of which would be affected by the mutation. These isoforms are composed of a thrombospondin-type laminin G (TSP) domain followed by seven tandemly organized epilepsy-associated repeats (EARs), probably forming a β-propeller domain. Tspear is expressed in a variety of murine tissues. Only the larger Tspear transcript was found in the cochlea, and the protein was detected by immunofluorescence at the surface of the hair bundles of sensory cells. The mammalian EAR protein family includes six known members. Defects in four of them, i.e. Lgi1, Lgi2, Vlgr1 and, we show here, TSPEAR, cause disorders with auditory features: epilepsy, which can include auditory features in humans; audiogenic seizures in animals; and/or hearing impairments in humans and mice. These observations demonstrate that EAR-containing proteins are essential for the development and function of the auditory system.
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Affiliation(s)
- Sedigheh Delmaghani
- Institut Pasteur, Unité de Génétique et Physiologie de l’Audition, Paris, France
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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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Kim HA, Park WJ, Jeong HS, Lee HE, Lee SH, Kwon NS, Baek KJ, Kim DS, Yun HY. Leucine-rich glioma inactivated 3 regulates adipogenesis through ADAM23. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:914-22. [PMID: 22405860 DOI: 10.1016/j.bbalip.2012.02.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/10/2012] [Accepted: 02/15/2012] [Indexed: 12/19/2022]
Abstract
Leucine-rich glioma inactivated 3 (LGI3) is a secreted protein and a member of LGI/epitempin family. We previously showed that LGI3 was highly expressed in brain and played regulatory roles in neuronal exocytosis and differentiation. Besides the nervous system, LGI3 was shown to be expressed in diverse tissues. In this study, we found that LGI3 and its receptor candidate ADAM23 were expressed in adipose tissues and 3T3-L1 cells. 3T3-L1 preadipocytes secreted a 60-kDa protein, a major secreted form of LGI3, which declined with adipocyte differentiation. LGI3 was also expressed in adipose tissue macrophages in the ob/ob mice and in macrophage cell line. The 60-kDa LGI3 protein was selectively increased in the ob/ob adipose tissues comparing with the lean mice. Pull-down experiments, coimmunoprecipitation and immunocytochemistry indicated that LGI3 associated with ADAM23 in adipose tissues and 3T3-L1 cells. Knockdown of LGI3 or ADAM23 by siRNA increased adipogenesis in 3T3-L1 cells. Treatment with LGI3 protein did not affect preadipocyte proliferation but attenuated adipogenesis and this effect was reversed by siRNA-mediated knockdown of ADAM23. Taken together, we propose that LGI3 may be a candidate adipokine that is perturbed in obesity and suppresses adipogenesis through its receptor, ADAM23.
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Affiliation(s)
- Hyun A Kim
- Department of Biochemistry, Chung-Ang University, College of Medicine, 84 Heukseok-ro, Seoul 156-861, Republic of Korea
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Zallocchi M, Meehan DT, Delimont D, Rutledge J, Gratton MA, Flannery J, Cosgrove D. Role for a novel Usher protein complex in hair cell synaptic maturation. PLoS One 2012; 7:e30573. [PMID: 22363448 PMCID: PMC3281840 DOI: 10.1371/journal.pone.0030573] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 12/22/2011] [Indexed: 12/22/2022] Open
Abstract
The molecular mechanisms underlying hair cell synaptic maturation are not well understood. Cadherin-23 (CDH23), protocadherin-15 (PCDH15) and the very large G-protein coupled receptor 1 (VLGR1) have been implicated in the development of cochlear hair cell stereocilia, while clarin-1 has been suggested to also play a role in synaptogenesis. Mutations in CDH23, PCDH15, VLGR1 and clarin-1 cause Usher syndrome, characterized by congenital deafness, vestibular dysfunction and retinitis pigmentosa. Here we show developmental expression of these Usher proteins in afferent spiral ganglion neurons and hair cell synapses. We identify a novel synaptic Usher complex comprised of clarin-1 and specific isoforms of CDH23, PCDH15 and VLGR1. To establish the in vivo relevance of this complex, we performed morphological and quantitative analysis of the neuronal fibers and their synapses in the Clrn1−/− mouse, which was generated by incomplete deletion of the gene. These mice showed a delay in neuronal/synaptic maturation by both immunostaining and electron microscopy. Analysis of the ribbon synapses in Ames waltzerav3J mice also suggests a delay in hair cell synaptogenesis. Collectively, these results show that, in addition to the well documented role for Usher proteins in stereocilia development, Usher protein complexes comprised of specific protein isoforms likely function in synaptic maturation as well.
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Affiliation(s)
- Marisa Zallocchi
- Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Daniel T. Meehan
- Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Duane Delimont
- Boys Town National Research Hospital, Omaha, Nebraska, United States of America
| | - Joseph Rutledge
- Otolaryngology-Head, Neck Surgery, St Louis University, St Louis, Missouri, United States of America
| | - Michael Anne Gratton
- Otolaryngology-Head, Neck Surgery, St Louis University, St Louis, Missouri, United States of America
| | - John Flannery
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Dominic Cosgrove
- Boys Town National Research Hospital, Omaha, Nebraska, United States of America
- University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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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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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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Busolin G, Malacrida S, Bisulli F, Striano P, Di Bonaventura C, Egeo G, Pasini E, Cianci V, Ferlazzo E, Bianchi A, Coppola G, Elia M, Mecarelli O, Gobbi G, Casellato S, Marchini M, Binelli S, Freri E, Granata T, Posar A, Parmeggiani A, Vigliano P, Boniver C, Aguglia U, Striano S, Tinuper P, Giallonardo AT, Michelucci R, Nobile C. Association of intronic variants of the KCNAB1 gene with lateral temporal epilepsy. Epilepsy Res 2011; 94:110-6. [DOI: 10.1016/j.eplepsyres.2011.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 12/17/2010] [Accepted: 01/23/2011] [Indexed: 11/16/2022]
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ADAM23, a Gene Related to LGI1, Is Not Linked to Autosomal Dominant Lateral Temporal Epilepsy. EPILEPSY RESEARCH AND TREATMENT 2011; 2011:258365. [PMID: 22937229 PMCID: PMC3428609 DOI: 10.1155/2011/258365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 12/01/2010] [Indexed: 11/18/2022]
Abstract
Autosomal dominant lateral temporal epilepsy (ADTLE) is an inherited epileptic syndrome characterized by ictal auditory symptoms or aphasia, negative MRI findings, and relatively benign evolution. Mutations responsible for ADLTE have been found in the LGI1 gene. The functions of the Lgi1 protein apparently are mediated by interactions with members of the ADAM protein family: it binds the postsynaptic receptor ADAM22 to regulate glutamate-AMPA currents at excitatory synapses and also the ADAM23 receptor to promote neurite outgrowth in vitro and dendritic arborization in vivo. Because alteration of each of these neuronal mechanisms may underlie ADLTE, ADAM22 and ADAM23 are candidate genes for this syndrome. In a previous work, we excluded a major role of ADAM22 in the aetiology of ADLTE. Here, we performed linkage analysis between microsatellite markers within or flanking the ADAM23 gene and ADLTE in 13 Italian families. The results exclude ADAM23 as major causative gene for ADLTE.
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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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Investigation of LGI1 as the antigen in limbic encephalitis previously attributed to potassium channels: a case series. Lancet Neurol 2010; 9:776-85. [PMID: 20580615 DOI: 10.1016/s1474-4422(10)70137-x] [Citation(s) in RCA: 696] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Voltage-gated potassium channels are thought to be the target of antibodies associated with limbic encephalitis. However, antibody testing using cells expressing voltage-gated potassium channels is negative; hence, we aimed to identify the real autoantigen associated with limbic encephalitis. METHODS We analysed sera and CSF of 57 patients with limbic encephalitis and antibodies attributed to voltage-gated potassium channels and 148 control individuals who had other disorders with or without antibodies against voltage-gated potassium channels. Immunohistochemistry, immunoprecipitation, and mass spectrometry were used to characterise the antigen. An assay with HEK293 cells transfected with leucine-rich, glioma-inactivated 1 (LGI1) and disintegrin and metalloproteinase domain-containing protein 22 (ADAM22) or ADAM23 was used as a serological test. The identity of the autoantigen was confirmed by immunoabsorption studies and immunostaining of Lgi1-null mice. FINDINGS Immunoprecipitation and mass spectrometry analyses showed that antibodies from patients with limbic encephalitis previously attributed to voltage-gated potassium channels recognise LGI1, a neuronal secreted protein that interacts with presynaptic ADAM23 and postsynaptic ADAM22. Immunostaining of HEK293 cells transfected with LGI1 showed that sera or CSF from patients, but not those from control individuals, recognised LGI1. Co-transfection of LGI1 with its receptors, ADAM22 or ADAM23, changed the pattern of reactivity and improved detection. LGI1 was confirmed as the autoantigen by specific abrogation of reactivity of sera and CSF from patients after immunoabsorption with LGI1-expressing cells and by comparative immunostaining of wild-type and Lgi1-null mice, which showed selective lack of reactivity in brains of Lgi1-null mice. One patient with limbic encephalitis and antibodies against LGI1 also had antibodies against CASPR2, an autoantigen we identified in some patients with encephalitis and seizures, Morvan's syndrome, and neuromyotonia. INTERPRETATION LGI1 is the autoantigen associated with limbic encephalitis previously attributed to voltage-gated potassium channels. The term limbic encephalitis associated with antibodies against voltage-gated potassium channels should be changed to limbic encephalitis associated with LGI1 antibodies, and this disorder should be classed as an autoimmune synaptic encephalopathy. FUNDING National Institutes of Health, National Cancer Institute, and Euroimmun.
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Limviphuvadh V, Chua LL, Eisenhaber F, Adhikari S, Maurer-Stroh S. Is LGI2 the candidate gene for partial epilepsy with pericentral spikes? J Bioinform Comput Biol 2010; 8:117-27. [PMID: 20183877 DOI: 10.1142/s0219720010004550] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 11/24/2009] [Accepted: 11/25/2009] [Indexed: 11/18/2022]
Abstract
Partial epilepsy with pericentral spikes (PEPS) is a familial epilepsy with disease locus mapped to human chromosome region 4p15; yet, the causative gene is unknown. In this work, arguments based on protein sequence analysis and patient-specific chromosomal deletions are provided for LGI2 as the prime candidate gene for PEPS among the 52 genes known at the genome locus 4p15. Furthermore, we suggest that two reports of patients that were not classified as PEPS but show very similar phenotypes and deletions in the PEPS disease locus, could in fact describe the same disease. To test this hypothesis, patients with diagnosed PEPS or the described similar phenotypes could be screened for mutations in LGI2 and other shortlisted candidate genes. The linkage between PEPS and its disease causing gene(s) would allow diagnosis of the disease based on genetic screening as well as hereditary studies. Furthermore, previous knowledge on molecular disease mechanisms of related LGI proteins, for example LGI1 and autosomal dominant lateral temporal epilepsy, could be applied to deepen the understanding of the PEPS disease mechanism at the molecular level, which may facilitate therapeutic intervention in the future. Supplementary Table is available at http://www.worldscinet.com/jbcb/.
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Affiliation(s)
- Vachiranee Limviphuvadh
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Singapore 138671, Singapore.
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Park WJ, Lim YY, Kwon NS, Baek KJ, Kim DS, Yun HY. Leucine-Rich Glioma Inactivated 3 Induces Neurite Outgrowth Through Akt and Focal Adhesion Kinase. Neurochem Res 2010; 35:789-96. [DOI: 10.1007/s11064-010-0136-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2010] [Indexed: 01/14/2023]
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Yu YE, Wen L, Silva J, Li Z, Head K, Sossey-Alaoui K, Pao A, Mei L, Cowell JK. Lgi1 null mutant mice exhibit myoclonic seizures and CA1 neuronal hyperexcitability. Hum Mol Genet 2010; 19:1702-11. [PMID: 20130004 DOI: 10.1093/hmg/ddq047] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
LGI1 in humans is responsible for a predisposition to autosomal dominant partial epilepsy with auditory features (ADPEAF). However, mechanisms of how LGI1 mutations cause epilepsy remain unclear. We have used a mouse chromosome engineering strategy to create a null mutation for the gene ortholog encoding LGI1. The Lgi1 null mutant mice show no gross overall developmental abnormalities from routine histopathological analysis. After 12-18 days of age, the homozygous mutant mice all exhibit myoclonic seizures accompanied by rapid jumping and running and die shortly thereafter. The heterozygous mutant mice do not develop seizures. Electrophysiological analysis demonstrates an enhanced excitatory synaptic transmission by increasing the release of the excitatory neurotransmitter glutamate, suggesting a basis for the seizure phenotype. This mouse model, therefore, provides novel insights into the mechanism behind ADPEAF and offers a new opportunity to study the mechanism behind the role of LGI1 in susceptibility to myoclonic seizures.
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Affiliation(s)
- Y Eugene Yu
- MCG Cancer Center, School of Medicine, Medical College of Georgia, Augusta, GA 30912, USA
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