1
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Deuis JR, Klasfauseweh T, Walker L, Vetter I. The 'dispanins' and related proteins in physiology and neurological disease. Trends Neurosci 2024:S0166-2236(24)00118-8. [PMID: 39025729 DOI: 10.1016/j.tins.2024.06.004] [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: 02/21/2024] [Revised: 05/15/2024] [Accepted: 06/21/2024] [Indexed: 07/20/2024]
Abstract
The dispanins are a family of 15 transmembrane proteins that have diverse and often unclear physiological functions. Many dispanins, including synapse differentiation induced gene 1 (SynDIG1), proline-rich transmembrane protein 1 (PRRT1)/SynDIG4, and PRRT2, are expressed in the central nervous system (CNS), where they are involved in the development of synapses, regulation of neurotransmitter release, and interactions with ion channels, including AMPA receptors (AMPARs). Others, including transmembrane protein 233 (TMEM233) and trafficking regulator of GLUT4-1 (TRARG1), are expressed in the peripheral nervous system (PNS); however, the function of these dispanins is less clear. Recently, a family of neurotoxins isolated from the giant Australian stinging tree was shown to target TMEM233 to modulate the function of voltage-gated sodium (NaV) channels, suggesting that the dispanins are inherently druggable. Here, we review current knowledge about the structure and function of the dispanins, in particular TMEM233 and its two most closely related homologs PRRT2 and TRARG1, which may be drug targets involved in neurological disease.
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Affiliation(s)
- Jennifer R Deuis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Tabea Klasfauseweh
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Lucinda Walker
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, QLD, Australia.
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2
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Xu JJ, Li HF, Wu ZY. Paroxysmal Kinesigenic Dyskinesia: Genetics and Pathophysiological Mechanisms. Neurosci Bull 2024; 40:952-962. [PMID: 38091244 PMCID: PMC11250761 DOI: 10.1007/s12264-023-01157-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/03/2023] [Indexed: 07/16/2024] Open
Abstract
Paroxysmal kinesigenic dyskinesia (PKD), the most common type of paroxysmal movement disorder, is characterized by sudden and brief attacks of choreoathetosis or dystonia triggered by sudden voluntary movements. PKD is mainly caused by mutations in the PRRT2 or TMEM151A gene. The exact pathophysiological mechanisms of PKD remain unclear, although the function of PRRT2 protein has been well characterized in the last decade. Based on abnormal ion channels and disturbed synaptic transmission in the absence of PRRT2, PKD may be channelopathy or synaptopathy, or both. In addition, the cerebellum is regarded as the key pathogenic area. Spreading depolarization in the cerebellum is tightly associated with dyskinetic episodes. Whereas, in PKD, other than the cerebellum, the role of the cerebrum including the cortex and thalamus needs to be further investigated.
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Affiliation(s)
- Jiao-Jiao Xu
- Department of Medical Genetics and Center for Rare Diseases, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
- Department of Neurology in the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Hong-Fu Li
- Department of Medical Genetics and Center for Rare Diseases, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
- Department of Neurology in the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Zhi-Ying Wu
- Department of Medical Genetics and Center for Rare Diseases, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
- Department of Neurology in the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, 310009, China.
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3
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Hatta D, Kanamoto K, Makiya S, Watanabe K, Kishino T, Kinoshita A, Yoshiura KI, Kurotaki N, Shirotani K, Iwata N. Proline-rich transmembrane protein 2 knock-in mice present dopamine-dependent motor deficits. J Biochem 2023; 174:561-570. [PMID: 37793168 DOI: 10.1093/jb/mvad074] [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: 08/05/2023] [Revised: 09/19/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023] Open
Abstract
Mutations of proline-rich transmembrane protein 2 (PRRT2) lead to dyskinetic disorders such as paroxysmal kinesigenic dyskinesia (PKD), which is characterized by attacks of involuntary movements precipitated by suddenly initiated motion, and some convulsive disorders. Although previous studies have shown that PKD might be caused by cerebellar dysfunction, PRRT2 has not been sufficiently analyzed in some motor-related regions, including the basal ganglia, where dopaminergic neurons are most abundant in the brain. Here, we generated several types of Prrt2 knock-in (KI) mice harboring mutations, such as c.672dupG, that mimics the human pathological mutation c.649dupC and investigated the contribution of Prrt2 to dopaminergic regulation. Regardless of differences in the frameshift sites, all truncating mutations abolished Prrt2 expression within the striatum and cerebral cortex, consistent with previous reports of similar Prrt2 mutant rodents, confirming the loss-of-function nature of these mutations. Importantly, administration of l-dopa, a precursor of dopamine, exacerbated rotarod performance, especially in Prrt2-KI mice. These findings suggest that dopaminergic dysfunction in the brain by the PRRT2 mutation might be implicated in a part of motor symptoms of PKD and related disorders.
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Key Words
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l-dopa
- Prrt2
- dopamine
- paroxysmal kinesigenic dyskinesia
- rotarod.Abbreviations:
BFIE, benign familial infantile epilepsy; BG, basal ganglia; DA, dopamine; gRNA, guide ribonucleic acid; KI, knock-in; Kif26b, kinesin family member 26b; KLH, Keyhole Limpet Hemocyanin; LID, l-dopa-induced dyskinesia; MBS, m-maleimidobenzoyl-N-hydroxysuccinimide ester; NMD, nonsense-mediated mRNA decay; PKD, paroxysmal kinesigenic dyskinesia; PRRT2, proline-rich transmembrane protein 2; SNARE, soluble N-ethylmaleimide-sensitive factor attachment protein receptor
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Affiliation(s)
- Daisuke Hatta
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
| | - Kaito Kanamoto
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
| | - Shiho Makiya
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
| | - Kaori Watanabe
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
| | - Tatsuya Kishino
- Division of Functional Genomics, Research Center for Advanced Genomics, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
- Leading Medical Research Core Unit, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
| | - Akira Kinoshita
- Department of Human Genetics, Atomic Bomb Disease Institute, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
- Leading Medical Research Core Unit, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
| | - Koh-Ichiro Yoshiura
- Department of Human Genetics, Atomic Bomb Disease Institute, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
- Leading Medical Research Core Unit, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
| | - Naohiro Kurotaki
- Department of Human Genetics, Atomic Bomb Disease Institute, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
| | - Keiro Shirotani
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
- Leading Medical Research Core Unit, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
| | - Nobuhisa Iwata
- Department of Genome-Based Drug Discovery, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki-shi, Nagasaki 852-8521, Japan
- Leading Medical Research Core Unit, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-shi, Nagasaki 852-8523, Japan
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4
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Sterlini B, Franchi F, Morinelli L, Corradi B, Parodi C, Albini M, Bianchi A, Marte A, Baldelli P, Alberini G, Maragliano L, Valente P, Benfenati F, Corradi A. Missense mutations in the membrane domain of PRRT2 affect its interaction with Nav1.2 voltage-gated sodium channels. Neurobiol Dis 2023:106177. [PMID: 37271286 DOI: 10.1016/j.nbd.2023.106177] [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: 04/14/2023] [Revised: 05/16/2023] [Accepted: 05/27/2023] [Indexed: 06/06/2023] Open
Abstract
PRRT2 is a neuronal protein that controls neuronal excitability and network stability by modulating voltage-gated Na+ channel (Nav). PRRT2 pathogenic variants cause pleiotropic syndromes including epilepsy, paroxysmal kinesigenic dyskinesia and episodic ataxia attributable to loss-of-function pathogenetic mechanism. Based on the evidence that the transmembrane domain of PRRT2 interacts with Nav1.2/1.6, we focused on eight missense mutations located within the domain that show expression and membrane localization similar to the wild-type protein. Molecular dynamics simulations showed that the mutants do not alter the structural stability of the PRRT2 membrane domain and preserve its conformation. Using affinity assays, we found that the A320V and V286M mutants displayed respectively decreased and increased binding to Nav1.2. Accordingly, surface biotinylation showed an increased Nav1.2 surface exposure induced by the A320V mutant. Electrophysiological analysis confirmed the lack of modulation of Nav1.2 biophysical properties by the A320V mutant with a loss-of-function phenotype, while the V286M mutant displayed a gain-of-function with respect to wild-type PRRT2 with a more pronounced left-shift of the inactivation kinetics and delayed recovery from inactivation. The data confirm the key role played by the PRRT2-Nav interaction in the pathogenesis of the PRRT2-linked disorders and suggest an involvement of the A320 and V286 residues in the interaction site. Given the similar clinical phenotype caused by the two mutations, we speculate that circuit instability and paroxysmal manifestations may arise when PRRT2 function is outside the physiological range.
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Affiliation(s)
- Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Francesca Franchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Lisastella Morinelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Beatrice Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Chiara Parodi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Martina Albini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Alessandra Bianchi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Antonella Marte
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Giulio Alberini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy.
| | - Anna Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, Genova 16132, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, Genova 16132, Italy.
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5
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Lin WS. Translating Genetic Discovery into a Mechanistic Understanding of Pediatric Movement Disorders: Lessons from Genetic Dystonias and Related Disorders. ADVANCED GENETICS (HOBOKEN, N.J.) 2023; 4:2200018. [PMID: 37288166 PMCID: PMC10242408 DOI: 10.1002/ggn2.202200018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Indexed: 06/09/2023]
Abstract
The era of next-generation sequencing has increased the pace of gene discovery in the field of pediatric movement disorders. Following the identification of novel disease-causing genes, several studies have aimed to link the molecular and clinical aspects of these disorders. This perspective presents the developing stories of several childhood-onset movement disorders, including paroxysmal kinesigenic dyskinesia, myoclonus-dystonia syndrome, and other monogenic dystonias. These stories illustrate how gene discovery helps focus the research efforts of scientists trying to understand the mechanisms of disease. The genetic diagnosis of these clinical syndromes also helps clarify the associated phenotypic spectra and aids the search for additional disease-causing genes. Collectively, the findings of previous studies have led to increased recognition of the role of the cerebellum in the physiology and pathophysiology of motor control-a common theme in many pediatric movement disorders. To fully exploit the genetic information garnered in the clinical and research arenas, it is crucial that corresponding multi-omics analyses and functional studies also be performed at scale. Hopefully, these integrated efforts will provide us with a more comprehensive understanding of the genetic and neurobiological bases of movement disorders in childhood.
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Affiliation(s)
- Wei-Sheng Lin
- Department of Pediatrics Taipei Veterans General Hospital Taipei 11217 Taiwan
- School of Medicine National Yang Ming Chiao Tung University Taipei 112304 Taiwan
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6
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Franchi F, Marte A, Corradi B, Sterlini B, Alberini G, Romei A, De Fusco A, Vogel A, Maragliano L, Baldelli P, Corradi A, Valente P, Benfenati F. The intramembrane COOH-terminal domain of PRRT2 regulates voltage-dependent Na + channels. J Biol Chem 2023; 299:104632. [PMID: 36958475 PMCID: PMC10164911 DOI: 10.1016/j.jbc.2023.104632] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/25/2023] Open
Abstract
Proline-rich transmembrane protein 2 (PRRT2) is the single causative gene for pleiotropic paroxysmal syndromes including epilepsy, kinesigenic dyskinesia, episodic ataxia and migraine. PRRT2 is a neuron-specific type-2 membrane protein with a COOH-terminal intramembrane domain and a long proline-rich NH2-terminal cytoplasmic region. A large array of experimental data indicates that PRRT2 is a neuron stability gene that negatively controls intrinsic excitability by regulating surface membrane localization and biophysical properties of voltage-dependent Na+ channels Nav1.2 and Nav1.6, but not Nav1.1. To further investigate the regulatory role of PRRT2, we studied the structural features of this membrane protein with molecular dynamics simulations, and its structure-function relationships with Nav1.2 channels by biochemical and electrophysiological techniques. We found that the intramembrane COOH-terminal region maintains a stable conformation over time, with the first transmembrane domain forming a helix-loop-helix motif within the bilayer. The unstructured NH2-terminal cytoplasmic region bound to the Nav1.2 better than the isolated COOH-terminal intramembrane domain, mimicking full-length PRRT2, while the COOH-terminal intramembrane domain was able to modulate Na+ current and channel biophysical properties, still maintaining the striking specificity for Nav1.2 vs Nav1.1. channels. The results identify PRRT2 as a dual-domain protein in which the NH2-terminal cytoplasmic region acts as a binding antenna for Na+ channels, while the COOH-terminal membrane domain regulates channel exposure on the membrane and its biophysical properties.
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Affiliation(s)
- Francesca Franchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Antonella Marte
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Beatrice Corradi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Bruno Sterlini
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Giulio Alberini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Alessandra Romei
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Antonio De Fusco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Alexander Vogel
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Luca Maragliano
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Anna Corradi
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy;.
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7
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Forrest MP, Dos Santos M, Piguel NH, Wang YZ, Hawkins NA, Bagchi VA, Dionisio LE, Yoon S, Simkin D, Martin-de-Saavedra MD, Gao R, Horan KE, George AL, LeDoux MS, Kearney JA, Savas JN, Penzes P. Rescue of neuropsychiatric phenotypes in a mouse model of 16p11.2 duplication syndrome by genetic correction of an epilepsy network hub. Nat Commun 2023; 14:825. [PMID: 36808153 PMCID: PMC9938216 DOI: 10.1038/s41467-023-36087-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 01/16/2023] [Indexed: 02/19/2023] Open
Abstract
Neuropsychiatric disorders (NPDs) are frequently co-morbid with epilepsy, but the biological basis of shared risk remains poorly understood. The 16p11.2 duplication is a copy number variant that confers risk for diverse NPDs including autism spectrum disorder, schizophrenia, intellectual disability and epilepsy. We used a mouse model of the 16p11.2 duplication (16p11.2dup/+) to uncover molecular and circuit properties associated with this broad phenotypic spectrum, and examined genes within the locus capable of phenotype reversal. Quantitative proteomics revealed alterations to synaptic networks and products of NPD risk genes. We identified an epilepsy-associated subnetwork that was dysregulated in 16p11.2dup/+ mice and altered in brain tissue from individuals with NPDs. Cortical circuits from 16p11.2dup/+ mice exhibited hypersynchronous activity and enhanced network glutamate release, which increased susceptibility to seizures. Using gene co-expression and interactome analysis, we show that PRRT2 is a major hub in the epilepsy subnetwork. Remarkably, correcting Prrt2 copy number rescued aberrant circuit properties, seizure susceptibility and social deficits in 16p11.2dup/+ mice. We show that proteomics and network biology can identify important disease hubs in multigenic disorders, and reveal mechanisms relevant to the complex symptomatology of 16p11.2 duplication carriers.
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Affiliation(s)
- Marc P Forrest
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Marc Dos Santos
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nicolas H Piguel
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Yi-Zhi Wang
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nicole A Hawkins
- Department of Pharmacology Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Vikram A Bagchi
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Leonardo E Dionisio
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Sehyoun Yoon
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Dina Simkin
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Pharmacology Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Maria Dolores Martin-de-Saavedra
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense, 28040, Madrid, Spain
| | - Ruoqi Gao
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Katherine E Horan
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Alfred L George
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Pharmacology Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Mark S LeDoux
- Department of Psychology, University of Memphis, Memphis, TN, 38152, USA
- Veracity Neuroscience LLC, Memphis, TN, 38157, USA
| | - Jennifer A Kearney
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Pharmacology Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Jeffrey N Savas
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Peter Penzes
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
- Center for Autism and Neurodevelopment, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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8
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Li ZY, Tian WT, Huang XJ, Cao L. The Pathogenesis of Paroxysmal Kinesigenic Dyskinesia: Current Concepts. Mov Disord 2023; 38:537-544. [PMID: 36718795 DOI: 10.1002/mds.29326] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/31/2022] [Accepted: 01/06/2023] [Indexed: 02/01/2023] Open
Abstract
Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by recurrent and transient episodes of involuntary movements, including dystonia, chorea, ballism, or a combination of these, which are typically triggered by sudden voluntary movement. Disturbance of the basal ganglia-thalamo-cortical circuit has long been considered the cause of involuntary movements. Impairment of the gating function of the basal ganglia can cause an aberrant output toward the thalamus, which in turn leads to excessive activation of the cerebral cortex. Structural and functional abnormalities in the basal ganglia, thalamus, and cortex and abnormal connections between these brain regions have been found in patients with PKD. Recent studies have highlighted the role of the cerebellum in PKD. Insufficient suppression from the cerebellar cortex to the deep cerebellar nuclei could lead to overexcitation of the thalamocortical pathway. Therefore, this literature review aims to provide a comprehensive overview of the current research progress to explore the neural circuits and pathogenesis of PKD and promote further understanding and outlook on the pathophysiological mechanism of movement disorders. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Zi-Yi Li
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wo-Tu Tian
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Jun Huang
- Department of Neurology and Institute of Neurology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Cao
- Department of Neurology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
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9
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Valente P, Marte A, Franchi F, Sterlini B, Casagrande S, Corradi A, Baldelli P, Benfenati F. A Push-Pull Mechanism Between PRRT2 and β4-subunit Differentially Regulates Membrane Exposure and Biophysical Properties of NaV1.2 Sodium Channels. Mol Neurobiol 2023; 60:1281-1296. [PMID: 36441479 PMCID: PMC9899197 DOI: 10.1007/s12035-022-03112-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 10/26/2022] [Indexed: 11/29/2022]
Abstract
Proline-rich transmembrane protein 2 (PRRT2) is a neuron-specific protein implicated in the control of neurotransmitter release and neural network stability. Accordingly, PRRT2 loss-of-function mutations associate with pleiotropic paroxysmal neurological disorders, including paroxysmal kinesigenic dyskinesia, episodic ataxia, benign familial infantile seizures, and hemiplegic migraine. PRRT2 is a negative modulator of the membrane exposure and biophysical properties of Na+ channels NaV1.2/NaV1.6 predominantly expressed in brain glutamatergic neurons. NaV channels form complexes with β-subunits that facilitate the membrane targeting and the activation of the α-subunits. The opposite effects of PRRT2 and β-subunits on NaV channels raises the question of whether PRRT2 and β-subunits interact or compete for common binding sites on the α-subunit, generating Na+ channel complexes with distinct functional properties. Using a heterologous expression system, we have observed that β-subunits and PRRT2 do not interact with each other and act as independent non-competitive modulators of NaV1.2 channel trafficking and biophysical properties. PRRT2 antagonizes the β4-induced increase in expression and functional activation of the transient and persistent NaV1.2 currents, without affecting resurgent current. The data indicate that β4-subunit and PRRT2 form a push-pull system that finely tunes the membrane expression and function of NaV channels and the intrinsic neuronal excitability.
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Affiliation(s)
- Pierluigi Valente
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132, Genova, Italy. .,IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genova, Italy.
| | - Antonella Marte
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy ,IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Francesca Franchi
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy ,Center for Synaptic Neuroscience and Technology, Istituto Italiano Di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Bruno Sterlini
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy ,Center for Synaptic Neuroscience and Technology, Istituto Italiano Di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Silvia Casagrande
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Anna Corradi
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy ,IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, Section of Physiology, University of Genova, Viale Benedetto XV, 3, 16132 Genova, Italy ,IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy
| | - Fabio Benfenati
- IRCCS, Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132, Genova, Italy. .,Center for Synaptic Neuroscience and Technology, Istituto Italiano Di Tecnologia, Largo Rosanna Benzi 10, 16132, Genova, Italy.
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10
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Park SM, Roache CE, Iffland PH, Moldenhauer HJ, Matychak KK, Plante AE, Lieberman AG, Crino PB, Meredith A. BK channel properties correlate with neurobehavioral severity in three KCNMA1-linked channelopathy mouse models. eLife 2022; 11:e77953. [PMID: 35819138 PMCID: PMC9275823 DOI: 10.7554/elife.77953] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
KCNMA1 forms the pore of BK K+ channels, which regulate neuronal and muscle excitability. Recently, genetic screening identified heterozygous KCNMA1 variants in a subset of patients with debilitating paroxysmal non-kinesigenic dyskinesia, presenting with or without epilepsy (PNKD3). However, the relevance of KCNMA1 mutations and the basis for clinical heterogeneity in PNKD3 has not been established. Here, we evaluate the relative severity of three KCNMA1 patient variants in BK channels, neurons, and mice. In heterologous cells, BKN999S and BKD434G channels displayed gain-of-function (GOF) properties, whereas BKH444Q channels showed loss-of-function (LOF) properties. The relative degree of channel activity was BKN999S > BKD434G>WT > BKH444Q. BK currents and action potential firing were increased, and seizure thresholds decreased, in Kcnma1N999S/WT and Kcnma1D434G/WT transgenic mice but not Kcnma1H444Q/WT mice. In a novel behavioral test for paroxysmal dyskinesia, the more severely affected Kcnma1N999S/WT mice became immobile after stress. This was abrogated by acute dextroamphetamine treatment, consistent with PNKD3-affected individuals. Homozygous Kcnma1D434G/D434G mice showed similar immobility, but in contrast, homozygous Kcnma1H444Q/H444Q mice displayed hyperkinetic behavior. These data establish the relative pathogenic potential of patient alleles as N999S>D434G>H444Q and validate Kcnma1N999S/WT mice as a model for PNKD3 with increased seizure propensity.
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Affiliation(s)
- Su Mi Park
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Cooper E Roache
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Philip H Iffland
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Hans J Moldenhauer
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Katia K Matychak
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Amber E Plante
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Abby G Lieberman
- Department of Pharmacology, University of Maryland School of MedicineBaltimoreUnited States
| | - Peter B Crino
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Andrea Meredith
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
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11
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赖 重, 陈 瑞, 钟 春, 吉 明, 李 兵. [Clinical phenotype and genetic features of 16p11.2 microdeletion-related epilepsy in children]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2022; 24:585-590. [PMID: 35644201 PMCID: PMC9154364 DOI: 10.7499/j.issn.1008-8830.2111110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/29/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVES To study the clinical phenotype and genetic features of 16p11.2 microdeletion-related epilepsy in children. METHODS The medical data of 200 children with epilepsy who underwent a genetic analysis of epilepsy by the whole exon sequencing technology were collected retrospectively, of whom 9 children with epilepsy had 16p11.2 microdeletion. The clinical phenotype and genetic features of the 9 children with 16p11.2 microdeletion were analyzed. RESULTS The detection rate of 16p11.2 microdeletion was 4.5% (9/200). The 9 children with 16p11.2 microdeletion were 3-10 months old. They experienced focal motor seizures with consciousness disturbance, and some of the seizures developed into generalized tonic-clonic seizures. The interictal electroencephalogram showed focal or multifocal epileptiform discharge, and all 9 children responded well to antiepileptic drugs. The 9 children had a 16p11.2 deletion fragment size of 398-906 kb, and the number of deleted genes was 23-33 which were all pathogenic mutations. The mutation was of maternal origin in 2 children, of paternal origin in 1 child, and de novo in the other children. CONCLUSIONS 16p11.2 microdeletion can be detected in some children with epilepsy. Most of the 16p11.2 microdeletion is de novo mutation and large gene fragment deletion. The onset of 16p11.2 microdeletion-related epilepsy in children is mostly within 1 year of life, and the epilepsy is drug-responsive.
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12
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Clinical and genetic analyses of 150 patients with paroxysmal kinesigenic dyskinesia. J Neurol 2022; 269:4717-4728. [DOI: 10.1007/s00415-022-11103-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 11/25/2022]
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13
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Zhong L, Song Y, Marziali F, Uzbekov R, Nguyen XN, Journo C, Roingeard P, Cimarelli A. A novel domain within the CIL regulates egress of IFITM3 from the Golgi and reveals a regulatory role of IFITM3 on the secretory pathway. Life Sci Alliance 2022; 5:5/7/e202101174. [PMID: 35396335 PMCID: PMC8994042 DOI: 10.26508/lsa.202101174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 03/24/2022] [Accepted: 03/25/2022] [Indexed: 12/30/2022] Open
Abstract
The InterFeron-Induced TransMembrane proteins (IFITMs) are members of the dispanin/CD225 family that act as broad viral inhibitors by preventing viral-to-cellular membrane fusion. In this study, we uncover egress from the Golgi as an important step in the biology of IFITM3 by identifying the domain that regulates this process and that similarly controls the egress of the dispanins IFITM1 and PRRT2, protein linked to paroxysmal kinesigenic dyskinesia. In the case of IFITM3, high levels of expression of wild-type, or mutations in the Golgi egress domain, lead to accumulation of IFITM3 in the Golgi and drive generalized glycoprotein trafficking defects. These defects can be relieved upon incubation with Amphotericin B, compound known to relieve IFITM-driven membrane fusion defects, as well as by v-SNARE overexpression, suggesting that IFITM3 interferes with membrane fusion processes important for Golgi functionalities. The comparison of glycoprotein trafficking in WT versus IFITMs-KO cells indicates that the modulation of the secretory pathway is a novel feature of IFITM proteins. Overall, our study defines a novel domain that regulates the egress of several dispanin/CD225 members from the Golgi and identifies a novel modulatory function for IFITM3.
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Affiliation(s)
- Li Zhong
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Yuxin Song
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Federico Marziali
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Rustem Uzbekov
- Plateforme IBiSA de Microscopie Electronique, Université de Tours et CHU de Tours, Tours, France,Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Xuan-Nhi Nguyen
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Chloé Journo
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | - Philippe Roingeard
- Plateforme IBiSA de Microscopie Electronique, Université de Tours et CHU de Tours, Tours, France,INSERM U1259, Université de Tours et CHU de Tours, Tours, France
| | - Andrea Cimarelli
- Centre International de Recherche en Infectiologie (CIRI), Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France,Correspondence:
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14
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LeDoux MS. No Neuron Operates in Isolation. Neurology 2022; 98:389-390. [PMID: 35058342 DOI: 10.1212/wnl.0000000000200062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Mark S LeDoux
- From the University of Memphis; and Veracity Neuroscience LLC, Memphis, TN.
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15
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Ekmen A, Meneret A, Valabregue R, Beranger B, Worbe Y, Lamy JC, Mehdi S, Herve A, Adanyeguh I, Temiz G, Damier P, Gras D, Roubertie A, Piard J, Navarro V, Mutez E, Riant F, Welniarz Q, Vidailhet M, Lehericy S, Meunier S, Gallea C, Roze E. Cerebellum Dysfunction in Patients With PRRT2-Related Paroxysmal Dyskinesia. Neurology 2022; 98:e1077-e1089. [DOI: 10.1212/wnl.0000000000200060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/03/2022] [Indexed: 11/15/2022] Open
Abstract
Background and Objectives:The main culprit gene for paroxysmal kinesigenic dyskinesia, characterized by brief and recurrent attacks of involuntary movements, is PRRT2. The location of the primary dysfunction associated with paroxysmal dyskinesia remains a matter of debate and may vary depending on the etiology. While striatal dysfunction has often been implicated in these patients, evidence from preclinical models indicate that the cerebellum could also play a role. We aimed to investigate the role of the cerebellum in the pathogenesis of PRRT2-related dyskinesia in humans.Methods:We enrolled 22 consecutive right-handed patients with paroxysmal kinesigenic dyskinesia with a pathogenic variant of PRRT2, and their matched controls. Participants underwent a multi-modal neuroimaging protocol. We recorded anatomic and diffusion-weighted MRI, as well as resting-state functional MRI during which we tested the after-effects of sham and repetitive transcranial magnetic stimulation applied to the cerebellum on endogenous brain activity. We quantified: (i) the structural integrity of gray matter using voxel-based morphometry; (ii) the structural integrity of white matter using fixel-based analysis; (iii) the strength and direction of functional cerebellar connections using spectral dynamic causal modeling.Results:PRRT2 patients had: (i) decreased gray matter volume in the cerebellar lobule VI and in the medial prefrontal cortex; (ii) microstructural alterations of white matter in the cerebellum and along the tracts connecting the cerebellum to the striatum and the cortical motor areas; (iii) dysfunction of cerebellar motor pathways to the striatum and the cortical motor areas, as well as abnormal communication between the associative cerebellum (Crus I) and the medial prefrontal cortex. Cerebellar stimulation modulated communication within the motor and associative cerebellar networks, and tended to restore this communication to the level observed in healthy controls.Discussion:Patients with PRRT2-related dyskinesia have converging structural alterations of the motor cerebellum and related pathways with a dysfunction of cerebellar output towards the cerebello-thalamo-striato-cortical network. We hypothesize that abnormal cerebellar output is the primary dysfunction in patients with a PRRT2 pathogenic variant, resulting in striatal dysregulation and paroxysmal dyskinesia. More broadly, striatal dysfunction in paroxysmal dyskinesia might be secondary to aberrant cerebellar output transmitted by thalamic relays in certain disorders.Clinical trial number:NCT03481491 (https://ichgcp.net/clinical-trials-registry/NCT03481491)
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16
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Motoyama R, Matsudaira T, Terada K, Usui N, Yoshiura KI, Takahashi Y. PRRT2 mutation in a Japanese woman: Adult-onset focal epilepsy coexisting with movement disorders and cerebellar atrophy. Epilepsy Behav Rep 2022; 19:100554. [PMID: 35712060 PMCID: PMC9194843 DOI: 10.1016/j.ebr.2022.100554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 04/23/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Mutation of the PRRT2 gene in a Japanese woman resulted in the c.604_607del variant. Her clinical features presented with focal epilepsy, cerebellar atrophy, paroxysmal kinesigenic dyskinesia, and paroxysmal non-kinesigenic dystonia (PNKD). Video-EEG monitoring revealed that her epilepsy arose from the left temporal region. Low dose lamotrigine was effective for her epilepsy and PNKD.
Proline-rich transmembrane protein 2 (PRRT2) was confirmed as the causative gene of paroxysmal kinesigenic dyskinesia (PKD) as shown by genome-wide linkage analyses. PRRT2 mutations are also associated with benign familial infantile seizures, infantile convulsions and choreoathetosis, and childhood absence epilepsy, but few reports have investigated adult-onset epilepsy. We describe here a rare presentation of adult-onset focal epilepsy with a PRRT2 mutation in a 31-year-old woman who showed cerebellar atrophy, familial paroxysmal kinesigenic dyskinesia, and paroxysmal non-kinesigenic dystonia. Video-electroencephalography (EEG) demonstrated focal impaired awareness seizures, in which ictal EEG changes showed left temporal onset with rhythmic theta activity over the left temporal region. Magnetic resonance imaging showed mild cerebellar atrophy. The administration of lamotrigine 50 mg/day resulted in freedom from her seizures and lamotrigine 150 mg/day reduced paroxysmal non-kinesigenic dystonia. Furthermore, she had a rare frameshift mutation, c.604_607del, p.Ser202fs of which the pathogenicity has been reported in ClinVar, but it has not been reported in Japan. Mutation of the PRRT2 gene can cause adult-onset epilepsy, paroxysmal non-kinesigenic movement disorder, and cerebellar atrophy, suggesting an expanding clinical phenotypic spectrum associated with PRRT2 mutations.
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17
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Transcranial direct current stimulation of cerebellum alters spiking precision in cerebellar cortex: A modeling study of cellular responses. PLoS Comput Biol 2021; 17:e1009609. [PMID: 34882680 PMCID: PMC8691604 DOI: 10.1371/journal.pcbi.1009609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 12/21/2021] [Accepted: 11/02/2021] [Indexed: 01/13/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) of the cerebellum has rapidly raised interest but the effects of tDCS on cerebellar neurons remain unclear. Assessing the cellular response to tDCS is challenging because of the uneven, highly stratified cytoarchitecture of the cerebellum, within which cellular morphologies, physiological properties, and function vary largely across several types of neurons. In this study, we combine MRI-based segmentation of the cerebellum and a finite element model of the tDCS-induced electric field (EF) inside the cerebellum to determine the field imposed on the cerebellar neurons throughout the region. We then pair the EF with multicompartment models of the Purkinje cell (PC), deep cerebellar neuron (DCN), and granule cell (GrC) and quantify the acute response of these neurons under various orientations, physiological conditions, and sequences of presynaptic stimuli. We show that cerebellar tDCS significantly modulates the postsynaptic spiking precision of the PC, which is expressed as a change in the spike count and timing in response to presynaptic stimuli. tDCS has modest effects, instead, on the PC tonic firing at rest and on the postsynaptic activity of DCN and GrC. In Purkinje cells, anodal tDCS shortens the repolarization phase following complex spikes (-14.7 ± 6.5% of baseline value, mean ± S.D.; max: -22.7%) and promotes burstiness with longer bursts compared to resting conditions. Cathodal tDCS, instead, promotes irregular spiking by enhancing somatic excitability and significantly prolongs the repolarization after complex spikes compared to baseline (+37.0 ± 28.9%, mean ± S.D.; max: +84.3%). tDCS-induced changes to the repolarization phase and firing pattern exceed 10% of the baseline values in Purkinje cells covering up to 20% of the cerebellar cortex, with the effects being distributed along the EF direction and concentrated in the area under the electrode over the cerebellum. Altogether, the acute effects of tDCS on cerebellum mainly focus on Purkinje cells and modulate the precision of the response to synaptic stimuli, thus having the largest impact when the cerebellar cortex is active. Since the spatiotemporal precision of the PC spiking is critical to learning and coordination, our results suggest cerebellar tDCS as a viable therapeutic option for disorders involving cerebellar hyperactivity such as ataxia. Transcranial direct current stimulation (tDCS) of the cerebellum is gaining momentum as a neuromodulation tool for the treatment of neurological diseases like movement disorders. Nonetheless, the response of cells in the cerebellum to tDCS is unclear and hardly generalizes from our understanding of tDCS of the cerebral cortex. We use computational models to investigate the response of several types of cerebellar neurons to the electric field induced by tDCS and show that, differently from the cerebral cortex, tDCS has significant acute effects on the cerebellar cortex. These effects (i) primarily alter the way Purkinje cells encode synaptic stimuli from the molecular layer and (ii) can help hyperactive cells regain postsynaptic spiking precision. Since the spatiotemporal precision of the Purkinje cell spiking is critical to learning and coordination, the study shows how tDCS can operate at the cellular level to treat movement disorders like tremor and ataxia.
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18
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Aj F, T M, C I, C BM, Kj N, H L, A N, Sm V, Y-H F, Lj P. Age-dependent neurological phenotypes in a mouse model of PRRT2-related diseases. Neurogenetics 2021; 22:171-185. [PMID: 34101060 PMCID: PMC8241743 DOI: 10.1007/s10048-021-00645-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
Paroxysmal kinesigenic dyskinesia is an episodic movement disorder caused by dominant mutations in the proline-rich transmembrane protein PRRT2, with onset in childhood and typically with improvement or resolution by middle age. Mutations in the same gene may also cause benign infantile seizures, which begin in the first year of life and typically remit by the age of 2 years. Many details of PRRT2 function at the synapse, and the effects of mutations on neuronal excitability in the pathophysiology of epilepsy and dyskinesia, have emerged through the work of several groups over the last decade. However, the age dependence of the phenotypes has not been explored in detail in transgenic models. Here, we report our findings in heterozygous and homozygous Prrt2 knockout mice that recapitulate the age dependence of dyskinesia seen in the human disease. We show that Prrt2 deletion reduces the levels of synaptic proteins in a dose-dependent manner that is most pronounced at postnatal day 5 (P5), attenuates at P60, and disappears by P180. In a test for foot slippage while crossing a balance beam, transient loss of coordination was most pronounced at P60 and less prominent at age extremes. Slower traverse time was noted in homozygous knockout mice only, consistent with the ataxia seen in rare individuals with biallelic loss of function mutations in Prrt2. We thus identify three age-dependent phenotypic windows in the mouse model, which recapitulate the pattern seen in humans with PRRT2-related diseases.
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Affiliation(s)
- Fay Aj
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - McMahon T
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Im C
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Bair-Marshall C
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Niesner Kj
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Li H
- Department of Psychiatry and Behavioral Sciences, University of California San Francisco, San Francisco, CA, 94143, USA.,Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, 94143, USA.,Kavli Institute for Fundamental Neuroscience, University of California San Francisco, 548F Rock Hall, MC-2922, 1550 4th Street, San Francisco, CA, 94143, USA
| | - Nelson A
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA.,Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, 94143, USA.,Kavli Institute for Fundamental Neuroscience, University of California San Francisco, 548F Rock Hall, MC-2922, 1550 4th Street, San Francisco, CA, 94143, USA.,Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Voglmaier Sm
- Department of Psychiatry and Behavioral Sciences, University of California San Francisco, San Francisco, CA, 94143, USA.,Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, 94143, USA.,Kavli Institute for Fundamental Neuroscience, University of California San Francisco, 548F Rock Hall, MC-2922, 1550 4th Street, San Francisco, CA, 94143, USA
| | - Fu Y-H
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA.,Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, 94143, USA.,Kavli Institute for Fundamental Neuroscience, University of California San Francisco, 548F Rock Hall, MC-2922, 1550 4th Street, San Francisco, CA, 94143, USA.,Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Ptáček Lj
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94143, USA. .,Weill Institute for Neuroscience, University of California San Francisco, San Francisco, CA, 94143, USA. .,Kavli Institute for Fundamental Neuroscience, University of California San Francisco, 548F Rock Hall, MC-2922, 1550 4th Street, San Francisco, CA, 94143, USA. .,Institute for Human Genetics, University of California San Francisco, San Francisco, CA, 94143, USA.
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19
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Landolfi A, Barone P, Erro R. The Spectrum of PRRT2-Associated Disorders: Update on Clinical Features and Pathophysiology. Front Neurol 2021; 12:629747. [PMID: 33746883 PMCID: PMC7969989 DOI: 10.3389/fneur.2021.629747] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in the PRRT2 (proline-rich transmembrane protein 2) gene have been identified as the main cause of an expanding spectrum of disorders, including paroxysmal kinesigenic dyskinesia and benign familial infantile epilepsy, which places this gene at the border between epilepsy and movement disorders. The clinical spectrum has largely expanded to include episodic ataxia, hemiplegic migraine, and complex neurodevelopmental disorders in cases with biallelic mutations. Prior to the discovery of PRRT2 as the causative gene for this spectrum of disorders, the sensitivity of paroxysmal kinesigenic dyskinesia to anticonvulsant drugs regulating ion channel function as well as the co-occurrence of epilepsy in some patients or families fostered the hypothesis this could represent a channelopathy. However, recent evidence implicates PRRT2 in synapse functioning, which disproves the "channel hypothesis" (although PRRT2 modulates ion channels at the presynaptic level), and justifies the classification of these conditions as synaptopathies, an emerging rubric of brain disorders. This review aims to provide an update of the clinical and pathophysiologic features of PRRT2-associated disorders.
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Affiliation(s)
| | | | - Roberto Erro
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana, ” University of Salerno, Baronissi, Italy
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Delorme C, Giron C, Bendetowicz D, Méneret A, Mariani LL, Roze E. Current challenges in the pathophysiology, diagnosis, and treatment of paroxysmal movement disorders. Expert Rev Neurother 2020; 21:81-97. [PMID: 33089715 DOI: 10.1080/14737175.2021.1840978] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Paroxysmal movement disorders mostly comprise paroxysmal dyskinesia and episodic ataxia, and can be the consequence of a genetic disorder or symptomatic of an acquired disease. AREAS COVERED In this review, the authors focused on certain hot-topic issues in the field: the respective contribution of the cerebellum and striatum to the generation of paroxysmal dyskinesia, the importance of striatal cAMP turnover in the pathogenesis of paroxysmal dyskinesia, the treatable causes of paroxysmal movement disorders not to be missed, with a special emphasis on the treatment strategy to bypass the glucose transport defect in paroxysmal movement disorders due to GLUT1 deficiency, and functional paroxysmal movement disorders. EXPERT OPINION Treatment of genetic causes of paroxysmal movement disorders is evolving towards precision medicine with targeted gene-specific therapy. Alteration of the cerebellar output and modulation of the striatal cAMP turnover offer new perspectives for experimental therapeutics, at least for paroxysmal movement disorders due to selected causes. Further characterization of cell-specific molecular pathways or network dysfunctions that are critically involved in the pathogenesis of paroxysmal movement disorders will likely result in the identification of new biomarkers and testing of innovative-targeted therapeutics.
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Affiliation(s)
- Cécile Delorme
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France
| | - Camille Giron
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France
| | - David Bendetowicz
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France.,Inserm U 1127, CNRS UMR 7225- Institut du cerveau (ICM), Sorbonne Université , Paris, France
| | - Aurélie Méneret
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France.,Inserm U 1127, CNRS UMR 7225- Institut du cerveau (ICM), Sorbonne Université , Paris, France
| | - Louise-Laure Mariani
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France.,Inserm U 1127, CNRS UMR 7225- Institut du cerveau (ICM), Sorbonne Université , Paris, France
| | - Emmanuel Roze
- Département de Neurologie, AP-HP, Hôpital Pitié-Salpêtrière , Paris, France.,Inserm U 1127, CNRS UMR 7225- Institut du cerveau (ICM), Sorbonne Université , Paris, France
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