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Hashimoto J, Fujita E, Tanimoto K, Kondo S, Matsumoto-Miyai K. Effects of Cardiac Glycoside Digoxin on Dendritic Spines and Motor Learning Performance in Mice. Neuroscience 2024; 541:77-90. [PMID: 38278474 DOI: 10.1016/j.neuroscience.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 01/28/2024]
Abstract
Synapse formation following the generation of postsynaptic dendritic spines is essential for motor learning and functional recovery after brain injury. The C-terminal fragment of agrin cleaved by neurotrypsin induces dendritic spine formation in the adult hippocampus. Since the α3 subunit of sodium-potassium ATPase (Na/K ATPase) is a neuronal receptor for agrin in the central nervous system, cardiac glycosides might facilitate dendritic spine formation and subsequent improvements in learning. This study investigated the effects of cardiac glycoside digoxin on dendritic spine turnover and learning performance in mice. Golgi-Cox staining revealed that intraperitoneal injection of digoxin less than its IC50 in the brain significantly increased the density of long spines (≥2 µm) in the cerebral cortex in wild-type mice and neurotrypsin-knockout (NT-KO) mice showing impairment of activity-dependent spine formation. Although the motor learning performance of NT-KO mice was significantly lower than control wild-type mice under the control condition, low doses of digoxin enhanced performance to a similar degree in both strains. In NT-KO mice, lower digoxin doses equivalent to clinical doses also significantly improved motor learning performance. These data suggest that lower doses of digoxin could modify dendritic spine formation or recycling and facilitate motor learning in compensation for the disruption of neurotrypsin-agrin pathway.
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Affiliation(s)
- Junichi Hashimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Erika Fujita
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Keisuke Tanimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Suzuo Kondo
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Kazumasa Matsumoto-Miyai
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan.
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2
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Miyata S, Tsuda M, Mitsui S. Overexpression of Motopsin, an Extracellular Serine Protease Related to Intellectual Disability, Promotes Adult Neurogenesis and Neuronal Responsiveness in the Dentate Gyrus. Mol Neurobiol 2023:10.1007/s12035-023-03890-y. [PMID: 38153682 DOI: 10.1007/s12035-023-03890-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 12/18/2023] [Indexed: 12/29/2023]
Abstract
Motopsin, a serine protease encoded by PRSS12, is secreted by neuronal cells into the synaptic clefts in an activity-dependent manner, where it induces synaptogenesis by modulating Na+/K+-ATPase activity. In humans, motopsin deficiency leads to severe intellectual disability and, in mice, it disturbs spatial memory and social behavior. In this study, we investigated mice that overexpressed motopsin in the forebrain using the Tet-Off system (DTG-OE mice). The elevated agrin cleavage or the reduced Na+/K+-ATPase activity was not detected. However, motopsin overexpression led to a reduction in spine density in hippocampal CA1 basal dendrites. While motopsin overexpression decreased the ratio of mature mushroom spines in the DG, it increased the ratio of immature thin spines in CA1 apical dendrites. Female DTG-OE mice showed elevated locomotor activity in their home cages. DTG-OE mice showed aberrant behaviors, such as delayed latency to the target hole in the Barnes maze test and prolonged duration of sniffing objects in the novel object recognition test (NOR), although they retained memory comparable to that of TRE-motopsin littermates, which normally express motopsin. After NOR, c-Fos-positive cells increased in the dentate gyrus (DG) of DTG-OE mice compared with that of DTG-SO littermates, in which motopsin overexpression was suppressed by the administration of doxycycline, and TRE-motopsin littermates. Notably, the numbers of doublecortin- and 5-bromo-2'-deoxyuridine-labeled cells significantly increased in the DG of DTG-OE mice, suggesting increased adult neurogenesis. Importantly, our results revealed a new function in addition to modulating neuronal responsiveness and spine morphology in the DG: the regulation of neurogenesis.
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Affiliation(s)
- Shiori Miyata
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma, 371-8514, Japan
| | - Masayuki Tsuda
- Division of Laboratory Animal Science, Science Research Center, Kochi Medical School, Kochi University, Oko-cho, Nankoku, Kochi, 783-8505, Japan
| | - Shinichi Mitsui
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma, 371-8514, Japan.
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3
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Prömer J, Barresi C, Herbst R. From phosphorylation to phenotype - Recent key findings on kinase regulation, downstream signaling and disease surrounding the receptor tyrosine kinase MuSK. Cell Signal 2023; 104:110584. [PMID: 36608736 DOI: 10.1016/j.cellsig.2022.110584] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/16/2022] [Accepted: 12/31/2022] [Indexed: 01/04/2023]
Abstract
Muscle-specific kinase (MuSK) is the key regulator of neuromuscular junction development. MuSK acts via several distinct pathways and is responsible for pre- and postsynaptic differentiation. MuSK is unique among receptor tyrosine kinases as activation and signaling are particularly tightly regulated. Initiation of kinase activity requires Agrin, a heparan sulphate proteoglycan derived from motor neurons, the low-density lipoprotein receptor-related protein-4 (Lrp4) and the intracellular adaptor protein Dok-7. There is a great knowledge gap between MuSK activation and downstream signaling. Recent studies using omics techniques have addressed this knowledge gap, thereby greatly contributing to a better understanding of MuSK signaling. Impaired MuSK signaling causes severe muscle weakness as described in congenital myasthenic syndromes or myasthenia gravis but the underlying pathophysiology is often unclear. This review focuses on recent advances in deciphering MuSK activation and downstream signaling. We further highlight latest break-throughs in understanding and treatment of MuSK-related disorders and discuss the role of MuSK in non-muscle tissue.
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Affiliation(s)
- Jakob Prömer
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Cinzia Barresi
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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4
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Mice deficient in synaptic protease neurotrypsin show impaired spaced long-term potentiation and blunted learning-induced modulation of dendritic spines. Cell Mol Life Sci 2023; 80:82. [PMID: 36871239 PMCID: PMC9986217 DOI: 10.1007/s00018-023-04720-z] [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: 06/10/2022] [Revised: 01/21/2023] [Accepted: 02/06/2023] [Indexed: 03/06/2023]
Abstract
Neurotrypsin (NT) is a neuronal trypsin-like serine protease whose mutations cause severe mental retardation in humans. NT is activated in vitro by Hebbian-like conjunction of pre- and postsynaptic activities, which promotes the formation of dendritic filopodia via proteolytic cleavage of the proteoglycan agrin. Here, we investigated the functional importance of this mechanism for synaptic plasticity, learning, and extinction of memory. We report that juvenile neurotrypsin-deficient (NT-/-) mice exhibit impaired long-term potentiation induced by a spaced stimulation protocol designed to probe the generation of new filopodia and their conversion into functional synapses. Behaviorally, juvenile NT-/- mice show impaired contextual fear memory and have a sociability deficit. The latter persists in aged NT-/- mice, which, unlike juvenile mice, show normal recall but impaired extinction of contextual fear memories. Structurally, juvenile mutants exhibit reduced spine density in the CA1 region, fewer thin spines, and no modulation in the density of dendritic spines following fear conditioning and extinction in contrast to wild-type littermates. The head width of thin spines is reduced in both juvenile and aged NT-/- mice. In vivo delivery of adeno-associated virus expressing an NT-generated fragment of agrin, agrin-22, but not a shorter agrin-15, elevates the spine density in NT-/- mice. Moreover, agrin-22 co-aggregates with pre- and postsynaptic markers and increases the density and size of presynaptic boutons and presynaptic puncta, corroborating the view that agrin-22 supports the synaptic growth.
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5
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Molecular Landscape of Tourette's Disorder. Int J Mol Sci 2023; 24:ijms24021428. [PMID: 36674940 PMCID: PMC9865021 DOI: 10.3390/ijms24021428] [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: 11/28/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/12/2023] Open
Abstract
Tourette's disorder (TD) is a highly heritable childhood-onset neurodevelopmental disorder and is caused by a complex interplay of multiple genetic and environmental factors. Yet, the molecular mechanisms underlying the disorder remain largely elusive. In this study, we used the available omics data to compile a list of TD candidate genes, and we subsequently conducted tissue/cell type specificity and functional enrichment analyses of this list. Using genomic data, we also investigated genetic sharing between TD and blood and cerebrospinal fluid (CSF) metabolite levels. Lastly, we built a molecular landscape of TD through integrating the results from these analyses with an extensive literature search to identify the interactions between the TD candidate genes/proteins and metabolites. We found evidence for an enriched expression of the TD candidate genes in four brain regions and the pituitary. The functional enrichment analyses implicated two pathways ('cAMP-mediated signaling' and 'Endocannabinoid Neuronal Synapse Pathway') and multiple biological functions related to brain development and synaptic transmission in TD etiology. Furthermore, we found genetic sharing between TD and the blood and CSF levels of 39 metabolites. The landscape of TD not only provides insights into the (altered) molecular processes that underlie the disease but, through the identification of potential drug targets (such as FLT3, NAALAD2, CX3CL1-CX3CR1, OPRM1, and HRH2), it also yields clues for developing novel TD treatments.
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Deconstruction of Neurotrypsin Reveals a Multi-factorially Regulated Activity Affecting Myotube Formation and Neuronal Excitability. Mol Neurobiol 2022; 59:7466-7485. [PMID: 36197591 PMCID: PMC9616769 DOI: 10.1007/s12035-022-03056-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022]
Abstract
Neurotrypsin (NT) is a highly specific nervous system multi-domain serine protease best known for its selective processing of the potent synaptic organizer agrin. Its enzymatic activity is thought to influence processes of synaptic plasticity, with its deregulation causing accelerated neuromuscular junction (NMJ) degeneration or contributing to forms of mental retardation. These biological effects are likely to stem from NT-based regulation of agrin signaling. However, dissecting the exact biological implications of NT-agrin interplay is difficult, due to the scarce molecular detail regarding NT activity and NT-agrin interactions. We developed a strategy to reliably produce and purify a catalytically competent engineered variant of NT called "NT-mini" and a library of C-terminal agrin fragments, with which we performed a thorough biochemical and biophysical characterization of NT enzyme functionality. We studied the regulatory effects of calcium ions and heparin, identified NT's heparin-binding domain, and discovered how zinc ions induce modulation of enzymatic activity. Additionally, we investigated myotube differentiation and hippocampal neuron excitability, evidencing a dose-dependent increase in neuronal activity alongside a negative impact on myoblast fusion when using the active NT enzyme. Collectively, our results provide in vitro and cellular foundations to unravel the molecular underpinnings and biological significance of NT-agrin interactions.
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Miyata S, Kashio T, Tsuchiya K, Mitsui S. Motopsin deficiency imparts partial insensitivity to doxorubicin-induced hippocampal impairments in adult mice. Neurosci Lett 2021; 763:136181. [PMID: 34416345 DOI: 10.1016/j.neulet.2021.136181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 08/12/2021] [Accepted: 08/14/2021] [Indexed: 10/20/2022]
Abstract
Motopsin is a serine protease that plays a crucial role in synaptic functions. Loss of motopsin function causes severe intellectual disability in humans. In this study, we evaluated the role of motopsin in the neuropathological development of cognitive impairments following chemotherapy, also known as chemobrain. Motopsin knockout (KO) and wild-type (WT) mice were intravenously injected with doxorubicin (Dox) or saline four times every 8 days and were evaluated for open field, novel object recognition, and passive avoidance tests. Parvalbumin-positive neurons in the hippocampus were immunohistochemically analyzed. Dox administration significantly decreased the total distance in the open field test in both WT and motopsin KO mice without affecting the duration spent in the center square. A significant interaction between the genotype and drug treatment was detected in the recognition index (the rate to investigate a novel object) in the novel object recognition test, although Dox treatment did not affect the total investigation time. Additionally, Dox treatment significantly decreased the recognition index in WT mice, whereas it tended to increase the recognition index in motopsin KO mice. Dox treatment did not affect the latency to enter a dark compartment in either WT or motopsin KO mice in the passive avoidance test. Interestingly, Dox treatment increased the parvalbumin-positive neurons in the stratum oriens of the hippocampus CA1 region of only WT mice, not motopsin KO mice. Our data suggest that motopsin deficiency imparted partial insensitivity to Dox-induced hippocampal impairments. Alternatively, motopsin may contribute to the neuropathology of chemobrain.
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Affiliation(s)
- Shiori Miyata
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma 371-8514, Japan
| | - Taiki Kashio
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma 371-8514, Japan
| | - Kenji Tsuchiya
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma 371-8514, Japan
| | - Shinichi Mitsui
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa, Maebashi, Gunma 371-8514, Japan.
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8
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Chiareli RA, Carvalho GA, Marques BL, Mota LS, Oliveira-Lima OC, Gomes RM, Birbrair A, Gomez RS, Simão F, Klempin F, Leist M, Pinto MCX. The Role of Astrocytes in the Neurorepair Process. Front Cell Dev Biol 2021; 9:665795. [PMID: 34113618 PMCID: PMC8186445 DOI: 10.3389/fcell.2021.665795] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes are highly specialized glial cells responsible for trophic and metabolic support of neurons. They are associated to ionic homeostasis, the regulation of cerebral blood flow and metabolism, the modulation of synaptic activity by capturing and recycle of neurotransmitters and maintenance of the blood-brain barrier. During injuries and infections, astrocytes act in cerebral defense through heterogeneous and progressive changes in their gene expression, morphology, proliferative capacity, and function, which is known as reactive astrocytes. Thus, reactive astrocytes release several signaling molecules that modulates and contributes to the defense against injuries and infection in the central nervous system. Therefore, deciphering the complex signaling pathways of reactive astrocytes after brain damage can contribute to the neuroinflammation control and reveal new molecular targets to stimulate neurorepair process. In this review, we present the current knowledge about the role of astrocytes in brain damage and repair, highlighting the cellular and molecular bases involved in synaptogenesis and neurogenesis. In addition, we present new approaches to modulate the astrocytic activity and potentiates the neurorepair process after brain damage.
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Affiliation(s)
| | | | | | - Lennia Soares Mota
- Department of Pharmacology, Federal University of Goias, Goiânia, Brazil
| | | | | | - Alexander Birbrair
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Renato Santiago Gomez
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fabrício Simão
- Research Division, Vascular Cell Biology, Joslin Diabetes Center and Harvard Medical School, Boston, MA, United States
| | | | - Marcel Leist
- Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
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9
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Dumas G, Goubran‐Botros H, Matondo M, Pagan C, Boulègue C, Chaze T, Chamot‐Rooke J, Maronde E, Bourgeron T. Mass-spectrometry analysis of the human pineal proteome during night and day and in autism. J Pineal Res 2021; 70:e12713. [PMID: 33368564 PMCID: PMC8047921 DOI: 10.1111/jpi.12713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022]
Abstract
The human pineal gland regulates day-night dynamics of multiple physiological processes, especially through the secretion of melatonin. Using mass-spectrometry-based proteomics and dedicated analysis tools, we identify proteins in the human pineal gland and analyze systematically their variation throughout the day and compare these changes in the pineal proteome between control specimens and donors diagnosed with autism. Results reveal diverse regulated clusters of proteins with, among others, catabolic carbohydrate process and cytoplasmic membrane-bounded vesicle-related proteins differing between day and night and/or control versus autism pineal glands. These data show novel and unexpected processes happening in the human pineal gland during the day/night rhythm as well as specific differences between autism donor pineal glands and those from controls.
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Affiliation(s)
- Guillaume Dumas
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
- Precision Psychiatry and Social Physiology laboratoryCHU Ste‐Justine Research CenterDepartment of PsychiatryUniversity of MontrealQuebecQCCanada
| | - Hany Goubran‐Botros
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
| | - Mariette Matondo
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Cécile Pagan
- Paris Descartes UniversityParisFrance
- Service de Biochimie et Biologie MoléculaireINSERM U942Hôpital LariboisièreAPHPParisFrance
| | - Cyril Boulègue
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Thibault Chaze
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Julia Chamot‐Rooke
- Institut PasteurUnité de Spectrométrie de Masse pour la Biologie (MSBio)Centre de Ressources et Recherches Technologiques (C2RT)USR 2000 CNRSParisFrance
| | - Erik Maronde
- Institute for Anatomy IIFaculty of MedicineGoethe UniversityFrankfurtGermany
| | - Thomas Bourgeron
- Human Genetics and Cognitive FunctionsInstitut PasteurUMR 3571 CNRSUniversity Paris DiderotParisFrance
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Hamza IM, Mobarak YM, Hafez HS. Hippocampus anatomical structure and distribution of agrin proteoglycan and ryanodine receptor expression boost bird food caching behavior. THE EUROPEAN ZOOLOGICAL JOURNAL 2021. [DOI: 10.1080/24750263.2021.1885757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- I. M. Hamza
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
| | - Y. M. Mobarak
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
| | - H. S. Hafez
- Faculty of Science, Zoology Department, Suez University, Suez, Egypt
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11
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Wang A, Xiao Y, Huang P, Liu L, Xiong J, Li J, Mao D, Liu L. Novel NtA and LG1 Mutations in Agrin in a Single Patient Causes Congenital Myasthenic Syndrome. Front Neurol 2020; 11:239. [PMID: 32328026 PMCID: PMC7160337 DOI: 10.3389/fneur.2020.00239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 03/12/2020] [Indexed: 12/27/2022] Open
Abstract
Congenital myasthenic syndrome (CMS) is a group of genetic disorders of neuromuscular transmission that is characterized by muscle weakness. A mutation in the gene encoding agrin (AGRN) is a rare cause of CMS, and only a few families or isolated cases have been reported. We reported a pediatric proband exhibiting muscle weakness in the trunk and limbs with skeletal malformation and intellectual disability and performed whole-exome sequencing (WES) of the proband parent-offspring trio. Results revealed a new compound heterozygous mutation in AGRN: c.125A>C (p.Glu42Ala) in the N-terminal agrin domain (NtA) and c.4516G>A (p.Ala1506Thr) in the laminin G1 domain (LG1). Bioinformatic analysis predicted the mutation as possibly pathogenic. The new compound heterozygous mutation in AGRN may disrupt agrin's known function of bridging laminin and α-dystroglycan and undermine the formation and maintenance of the neuromuscular junction (NMJ) via both muscular and neural agrin pathways. It may also induce secondary peripheral neuropathy and skeletal malformation.
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Affiliation(s)
- Aiping Wang
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yangyang Xiao
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Peng Huang
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Lingjuan Liu
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jie Xiong
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jian Li
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Ding'an Mao
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Liqun Liu
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Pediatrics Neurology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
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12
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Ding Y, Zhao J, Zhang X, Wang S, Viola KL, Chow FE, Zhang Y, Lippa C, Klein WL, Gong Y. Amyloid Beta Oligomers Target to Extracellular and Intracellular Neuronal Synaptic Proteins in Alzheimer's Disease. Front Neurol 2019; 10:1140. [PMID: 31736856 PMCID: PMC6838211 DOI: 10.3389/fneur.2019.01140] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/11/2019] [Indexed: 12/19/2022] Open
Abstract
Introduction: β-Amyloid protein (Aβ) putatively plays a seminal role in synaptic loss in Alzheimer's disease (AD). While there is no consensus regarding the synaptic-relevant species of Aβ, it is known that Aβ oligomers (AβOs) are noticeably increased in the early stages of AD, localizing at or within the synapse. In cell and animal models, AβOs have been shown to attach to synapses and instigate synapse dysfunction and deterioration. To establish the pathological mechanism of synaptic loss in AD, it will be important to identify the synaptic targets to which AβOs attach. Methods: An unbiased approach using far western ligand blots has identified three synaptic proteins to which AβOs specifically attach. These proteins (p100, p140, and p260) were subsequently enriched by detergent extraction, ultracentrifugation, and CHT-HPLC column separation, and sequenced by LC-MS/MS. P100, p140, and p260 were identified. These levels of AβOs targets in human AD and aging frontal cortexes were analyzed by quantitative proteomics and western-blot. The polyclonal antibody to AβOs was developed and used to block the toxicity of AβOs. The data were analyzed with one-way analysis of variance. Results: AβOs binding proteins p100, p140, and p260 were identified as Na/K-ATPase, synGap, and Shank3, respectively. α3-Na/K-ATPase, synGap, and Shank3 proteins showed loss in the postsynaptic density (PSD) of human AD frontal cortex. In short term experiments, oligomers of Aβ inhibited Na/K-ATPase at the synapse. Na/K-ATPase activity was restored by an antibody specific for soluble forms of Aβ. α3-Na/K-ATPase protein and synaptic β-amyloid peptides were pulled down from human AD synapses by co-immunoprecipitation. Results suggest synaptic dysfunction in early stages of AD may stem from inhibition of Na/K-ATPase activity by Aβ oligomers, while later stages could hypothetically result from disrupted synapse structure involving the PSD proteins synGap and Shank3. Conclusion: We identified three AβO binding proteins as α3-Na/K-ATPase, synGap, and Shank3. Soluble Aβ oligomers appear capable of attacking neurons via specific extracellular as well as intracellular synaptic proteins. Impact on these proteins hypothetically could lead to synaptic dysfunction and loss, and could serve as novel therapeutic targets for AD treatment by antibodies or other agents.
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Affiliation(s)
- Yu Ding
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jiahui Zhao
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xunle Zhang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Shanshan Wang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Kirsten L. Viola
- Department of Neurobiology and Neurology, Northwestern University, Evanston, IL, United States
| | - Frances E. Chow
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Yang Zhang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
| | - Carol Lippa
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - William L. Klein
- Department of Neurobiology and Neurology, Northwestern University, Evanston, IL, United States
| | - Yuesong Gong
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Department of Biopharmaceutics and Food Science, Nanjing University of Chinese Medicine, Nanjing, China
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA, United States
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Shrivastava AN, Triller A, Melki R. Cell biology and dynamics of Neuronal Na +/K +-ATPase in health and diseases. Neuropharmacology 2018; 169:107461. [PMID: 30550795 DOI: 10.1016/j.neuropharm.2018.12.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/17/2018] [Accepted: 12/08/2018] [Indexed: 10/27/2022]
Abstract
Neuronal Na+/K+-ATPase is responsible for the maintenance of ionic gradient across plasma membrane. In doing so, in a healthy brain, Na+/K+-ATPase activity accounts for nearly half of total brain energy consumption. The α3-subunit containing Na+/K+-ATPase expression is restricted to neurons. Heterozygous mutations within α3-subunit leads to Rapid-onset Dystonia Parkinsonism, Alternating Hemiplegia of Childhood and other neurological and neuropsychiatric disorders. Additionally, proteins such as α-synuclein, amyloid-β, tau and SOD1 whose aggregation is associated to neurodegenerative diseases directly bind and impair α3-Na+/K+-ATPase activity. The review will provide a summary of neuronal α3-Na+/K+-ATPase functional properties, expression pattern, protein-protein interactions at the plasma membrane, biophysical properties (distribution and lateral diffusion). Lastly, the role of α3-Na+/K+-ATPase in neurological and neurodegenerative disorders will be discussed. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Amulya Nidhi Shrivastava
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France.
| | - Antoine Triller
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, INSERM, CNRS, PSL, Research University, 46 Rue d'Ulm, 75005 Paris, France
| | - Ronald Melki
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
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14
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Na +/K +-pump and neurotransmitter membrane receptors. INVERTEBRATE NEUROSCIENCE 2018; 19:1. [PMID: 30488358 PMCID: PMC6267510 DOI: 10.1007/s10158-018-0221-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/17/2018] [Indexed: 02/06/2023]
Abstract
Na+/K+-pump is an electrogenic transmembrane ATPase located in the outer plasma membrane of cells. The Na+/K+-ATPase pumps 3 sodium ions out of cells while pumping 2 potassium ions into cells. Both cations move against their concentration gradients. This enzyme's electrogenic nature means that it has a chronic role in stabilizing the resting membrane potential of the cell, in regulating the cell volume and in the signal transduction of the cell. This review will mainly consider the role of the Na+/K+-pump in neurons, with an emphasis on its role in modulating neurotransmitter receptor. Most of the literature on the modulation of neurotransmitter receptors refers to the situation in the mammalian nervous system, but the position is likely to be similar in most, if not all, invertebrate nervous systems.
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15
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Ferrer-Ferrer M, Dityatev A. Shaping Synapses by the Neural Extracellular Matrix. Front Neuroanat 2018; 12:40. [PMID: 29867379 PMCID: PMC5962695 DOI: 10.3389/fnana.2018.00040] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/25/2018] [Indexed: 11/13/2022] Open
Abstract
Accumulating data support the importance of interactions between pre- and postsynaptic neuronal elements with astroglial processes and extracellular matrix (ECM) for formation and plasticity of chemical synapses, and thus validate the concept of a tetrapartite synapse. Here we outline the major mechanisms driving: (i) synaptogenesis by secreted extracellular scaffolding molecules, like thrombospondins (TSPs), neuronal pentraxins (NPs) and cerebellins, which respectively promote presynaptic, postsynaptic differentiation or both; (ii) maturation of synapses via reelin and integrin ligands-mediated signaling; and (iii) regulation of synaptic plasticity by ECM-dependent control of induction and consolidation of new synaptic configurations. Particularly, we focused on potential importance of activity-dependent concerted activation of multiple extracellular proteases, such as ADAMTS4/5/15, MMP9 and neurotrypsin, for permissive and instructive events in synaptic remodeling through localized degradation of perisynaptic ECM and generation of proteolytic fragments as inducers of synaptic plasticity.
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Affiliation(s)
- Maura Ferrer-Ferrer
- Molecular Neuroplasticity German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.,Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
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16
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Fundamental Molecules and Mechanisms for Forming and Maintaining Neuromuscular Synapses. Int J Mol Sci 2018; 19:ijms19020490. [PMID: 29415504 PMCID: PMC5855712 DOI: 10.3390/ijms19020490] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 01/24/2018] [Accepted: 01/29/2018] [Indexed: 02/08/2023] Open
Abstract
The neuromuscular synapse is a relatively large synapse with hundreds of active zones in presynaptic motor nerve terminals and more than ten million acetylcholine receptors (AChRs) in the postsynaptic membrane. The enrichment of proteins in presynaptic and postsynaptic membranes ensures a rapid, robust, and reliable synaptic transmission. Over fifty years ago, classic studies of the neuromuscular synapse led to a comprehensive understanding of how a synapse looks and works, but these landmark studies did not reveal the molecular mechanisms responsible for building and maintaining a synapse. During the past two-dozen years, the critical molecular players, responsible for assembling the specialized postsynaptic membrane and regulating nerve terminal differentiation, have begun to be identified and their mechanism of action better understood. Here, we describe and discuss five of these key molecular players, paying heed to their discovery as well as describing their currently understood mechanisms of action. In addition, we discuss the important gaps that remain to better understand how these proteins act to control synaptic differentiation and maintenance.
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17
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Pohlkamp T, Wasser CR, Herz J. Functional Roles of the Interaction of APP and Lipoprotein Receptors. Front Mol Neurosci 2017; 10:54. [PMID: 28298885 PMCID: PMC5331069 DOI: 10.3389/fnmol.2017.00054] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/16/2017] [Indexed: 11/24/2022] Open
Abstract
The biological fates of the key initiator of Alzheimer’s disease (AD), the amyloid precursor protein (APP), and a family of lipoprotein receptors, the low-density lipoprotein (LDL) receptor-related proteins (LRPs) and their molecular roles in the neurodegenerative disease process are inseparably interwoven. Not only does APP bind tightly to the extracellular domains (ECDs) of several members of the LRP group, their intracellular portions are also connected through scaffolds like the one established by FE65 proteins and through interactions with adaptor proteins such as X11/Mint and Dab1. Moreover, the ECDs of APP and LRPs share common ligands, most notably Reelin, a regulator of neuronal migration during embryonic development and modulator of synaptic transmission in the adult brain, and Agrin, another signaling protein which is essential for the formation and maintenance of the neuromuscular junction (NMJ) and which likely also has critical, though at this time less well defined, roles for the regulation of central synapses. Furthermore, the major independent risk factors for AD, Apolipoprotein (Apo) E and ApoJ/Clusterin, are lipoprotein ligands for LRPs. Receptors and ligands mutually influence their intracellular trafficking and thereby the functions and abilities of neurons and the blood-brain-barrier to turn over and remove the pathological product of APP, the amyloid-β peptide. This article will review and summarize the molecular mechanisms that are shared by APP and LRPs and discuss their relative contributions to AD.
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Affiliation(s)
- Theresa Pohlkamp
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA
| | - Catherine R Wasser
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical CenterDallas, TX, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical CenterDallas, TX, USA; Department of Neuroscience, UT Southwestern Medical CenterDallas, TX, USA; Department of Neurology and Neurotherapeutics, UT Southwestern Medical CenterDallas, TX, USA
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18
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Dynamic light scattering: a practical guide and applications in biomedical sciences. Biophys Rev 2016; 8:409-427. [PMID: 28510011 DOI: 10.1007/s12551-016-0218-6] [Citation(s) in RCA: 806] [Impact Index Per Article: 100.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/08/2016] [Indexed: 10/20/2022] Open
Abstract
Dynamic light scattering (DLS), also known as photon correlation spectroscopy (PCS), is a very powerful tool for studying the diffusion behaviour of macromolecules in solution. The diffusion coefficient, and hence the hydrodynamic radii calculated from it, depends on the size and shape of macromolecules. In this review, we provide evidence of the usefulness of DLS to study the homogeneity of proteins, nucleic acids, and complexes of protein-protein or protein-nucleic acid preparations, as well as to study protein-small molecule interactions. Further, we provide examples of DLS's application both as a complementary method to analytical ultracentrifugation studies and as a screening tool to validate solution scattering models using determined hydrodynamic radii.
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Smedemark-Margulies N, Brownstein CA, Vargas S, Tembulkar SK, Towne MC, Shi J, Gonzalez-Cuevas E, Liu KX, Bilguvar K, Kleiman RJ, Han MJ, Torres A, Berry GT, Yu TW, Beggs AH, Agrawal PB, Gonzalez-Heydrich J. A novel de novo mutation in ATP1A3 and childhood-onset schizophrenia. Cold Spring Harb Mol Case Stud 2016; 2:a001008. [PMID: 27626066 PMCID: PMC5002930 DOI: 10.1101/mcs.a001008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We describe a child with onset of command auditory hallucinations and behavioral regression at 6 yr of age in the context of longer standing selective mutism, aggression, and mild motor delays. His genetic evaluation included chromosomal microarray analysis and whole-exome sequencing. Sequencing revealed a previously unreported heterozygous de novo mutation c.385G>A in ATP1A3, predicted to result in a p.V129M amino acid change. This gene codes for a neuron-specific isoform of the catalytic α-subunit of the ATP-dependent transmembrane sodium–potassium pump. Heterozygous mutations in this gene have been reported as causing both sporadic and inherited forms of alternating hemiplegia of childhood and rapid-onset dystonia parkinsonism. We discuss the literature on phenotypes associated with known variants in ATP1A3, examine past functional studies of the role of ATP1A3 in neuronal function, and describe a novel clinical presentation associated with mutation of this gene.
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Affiliation(s)
- Niklas Smedemark-Margulies
- Division of Immunology, Harvard Medical School, Boston, Massachusetts 02115, USA;; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Catherine A Brownstein
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sigella Vargas
- Developmental Neuropsychiatry Research Program, Department of Psychiatry, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Sahil K Tembulkar
- Developmental Neuropsychiatry Research Program, Department of Psychiatry, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Meghan C Towne
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Jiahai Shi
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Elisa Gonzalez-Cuevas
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Kevin X Liu
- Developmental Neuropsychiatry Research Program, Department of Psychiatry, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Kaya Bilguvar
- Department of Genetics, Yale Center for Genome Analysis, Yale School of Medicine, New Haven, Connecticut 06511, USA
| | - Robin J Kleiman
- Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA;; Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Min-Joon Han
- Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA;; Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Alcy Torres
- Division of Pediatric Neurology, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Gerard T Berry
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Timothy W Yu
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Alan H Beggs
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Pankaj B Agrawal
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA;; Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Joseph Gonzalez-Heydrich
- Developmental Neuropsychiatry Research Program, Department of Psychiatry, Boston Children's Hospital, Boston, Massachusetts 02115, USA;; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Evaluation of the Nicotinic Acetylcholine Receptor-Associated Proteome at Baseline and Following Nicotine Exposure in Human and Mouse Cortex. eNeuro 2016; 3:eN-NWR-0166-16. [PMID: 27559543 PMCID: PMC4985585 DOI: 10.1523/eneuro.0166-16.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/29/2016] [Accepted: 07/29/2016] [Indexed: 12/15/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) support the initiation and maintenance of smoking, but the long-term changes occurring in the protein complex as a result of smoking and the nicotine in tobacco are not known. Human studies and animal models have also demonstrated that increasing cholinergic tone increases behaviors related to depression, suggesting that the nAChR-associated proteome could be altered in individuals with mood disorders. We therefore immunopurified nAChRs and associated proteins for quantitative proteomic assessment of changes in protein–protein interactions of high-affinity nAChRs containing the β2 subunit (β2*-nAChRs) from either cortex of mice treated with saline or nicotine, or postmortem human temporal cortex tissue from tobacco-exposed and nonexposed individuals, with a further comparison of diagnosed mood disorder to control subjects. We observed significant effects of nicotine exposure on the β2*-nAChR-associated proteome in human and mouse cortex, particularly in the abundance of the nAChR subunits themselves, as well as putative interacting proteins that make up core components of neuronal excitability (Na/K ATPase subunits), presynaptic neurotransmitter release (syntaxins, SNAP25, synaptotagmin), and a member of a known nAChR protein chaperone family (14-3-3ζ). These findings identify candidate-signaling proteins that could mediate changes in cholinergic signaling via nicotine or tobacco use. Further analysis of identified proteins will determine whether these interactions are essential for primary function of nAChRs at presynaptic terminals. The identification of differences in the nAChR-associated proteome and downstream signaling in subjects with various mood disorders may also identify novel etiological mechanisms and reveal new treatment targets.
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21
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Harden N, Wang SJH, Krieger C. Making the connection – shared molecular machinery and evolutionary links underlie the formation and plasticity of occluding junctions and synapses. J Cell Sci 2016; 129:3067-76. [DOI: 10.1242/jcs.186627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
The pleated septate junction (pSJ), an ancient structure for cell–cell contact in invertebrate epithelia, has protein components that are found in three more-recent junctional structures, the neuronal synapse, the paranodal region of the myelinated axon and the vertebrate epithelial tight junction. These more-recent structures appear to have evolved through alterations of the ancestral septate junction. During its formation in the developing animal, the pSJ exhibits plasticity, although the final structure is extremely robust. Similar to the immature pSJ, the synapse and tight junctions both exhibit plasticity, and we consider evidence that this plasticity comes at least in part from the interaction of members of the immunoglobulin cell adhesion molecule superfamily with highly regulated membrane-associated guanylate kinases. This plasticity regulation probably arose in order to modulate the ancestral pSJ and is maintained in the derived structures; we suggest that it would be beneficial when studying plasticity of one of these structures to consider the literature on the others. Finally, looking beyond the junctions, we highlight parallels between epithelial and synaptic membranes, which both show a polarized distribution of many of the same proteins – evidence that determinants of apicobasal polarity in epithelia also participate in patterning of the synapse.
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Affiliation(s)
- Nicholas Harden
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon Ji Hau Wang
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
| | - Charles Krieger
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
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22
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Shen C, Xiong WC, Mei L. LRP4 in neuromuscular junction and bone development and diseases. Bone 2015; 80:101-108. [PMID: 26071838 DOI: 10.1016/j.bone.2015.05.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 05/04/2015] [Accepted: 05/08/2015] [Indexed: 02/08/2023]
Abstract
Low-density lipoprotein receptor-related protein 4 (LRP4) is a member of the low-density lipoprotein receptor (LDLR) family. Recent studies have revealed multiple functions and complex signaling mechanisms of LRP4 in different organs and tissues. LPR4 mutation or malfunction has been implicated in neurological disorders including congenital myasthenic syndrome, myasthenia gravis, and diseases of bone or kidney. This article is part of a Special Issue entitled "Muscle Bone Interactions".
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Affiliation(s)
- Chengyong Shen
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Wen-Cheng Xiong
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA.
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23
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Laird JG, Pan Y, Modestou M, Yamaguchi DM, Song H, Sokolov M, Baker SA. Identification of a VxP Targeting Signal in the Flagellar Na+ /K+ -ATPase. Traffic 2015; 16:1239-53. [PMID: 26373354 DOI: 10.1111/tra.12332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 09/11/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022]
Abstract
Na(+) /K(+) -ATPase (NKA) participates in setting electrochemical gradients, cardiotonic steroid signaling and cellular adhesion. Distinct isoforms of NKA are found in different tissues and subcellular localization patterns. For example, NKA α1 is widely expressed, NKA α3 is enriched in neurons and NKA α4 is a testes-specific isoform found in sperm flagella. In some tissues, ankyrin, a key component of the membrane cytoskeleton, can regulate the trafficking of NKA. In the retina, NKA and ankyrin-B are expressed in multiple cell types and immunostaining for each is striking in the synaptic layers. Labeling for NKA is also prominent along the inner segment plasma membrane (ISPM) of photoreceptors. NKA co-immunoprecipitates with ankyrin-B, but on a subcellular level colocalization of these two proteins varies dependent on the cell type. We used transgenic Xenopus laevis tadpoles to evaluate the subcellular trafficking of NKA in photoreceptors. GFP-NKA α3 and α1 are localized to the ISPM, but α4 is localized to outer segments (OSs). We identified a VxP motif responsible for the OS targeting by using a series of chimeric and mutant NKA constructs. This motif is similar to previously identified ciliary targeting motifs. Given the structural similarities between OSs and flagella, our findings shed light on the subcellular targeting of this testes-specific NKA isoform.
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Affiliation(s)
- Joseph G Laird
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.,Current address: Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Modestos Modestou
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - David M Yamaguchi
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Hongman Song
- Department of Ophthalmology, West Virginia University School of Medicine and West Virginia University Eye Institute, Morgantown, WV, 26506, USA.,Current address: Section for Translational Research in Retina & Macular Degeneration, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, 20892, USA
| | - Maxim Sokolov
- Department of Ophthalmology, West Virginia University School of Medicine and West Virginia University Eye Institute, Morgantown, WV, 26506, USA
| | - Sheila A Baker
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
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Integrated analyses of zebrafish miRNA and mRNA expression profiles identify miR-29b and miR-223 as potential regulators of optic nerve regeneration. BMC Genomics 2015; 16:591. [PMID: 26265132 PMCID: PMC4534052 DOI: 10.1186/s12864-015-1772-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 07/14/2015] [Indexed: 12/27/2022] Open
Abstract
Background Unlike mammals, zebrafish have the ability to regenerate damaged parts of their central nervous system (CNS) and regain functionality of the affected area. A better understanding of the molecular mechanisms involved in zebrafish regeneration may therefore provide insight into how CNS repair might be induced in mammals. Although many studies have described differences in gene expression in zebrafish during CNS regeneration, the regulatory mechanisms underpinning the differential expression of these genes have not been examined. Results We used microarrays to analyse and integrate the mRNA and microRNA (miRNA) expression profiles of zebrafish retina after optic nerve crush to identify potential regulatory mechanisms that underpin central nerve regeneration. Bioinformatic analysis identified 3 miRNAs and 657 mRNAs that were differentially expressed after injury. We then combined inverse correlations between our miRNA expression and mRNA expression, and integrated these findings with target predictions from TargetScan Fish to identify putative miRNA-gene target pairs. We focused on two over-expressed miRNAs (miR-29b and miR-223), and functionally validated seven of their predicted gene targets using RT-qPCR and luciferase assays to confirm miRNA-mRNA binding. Gene ontology analysis placed the miRNA-regulated genes (eva1a, layna, nefmb, ina, si:ch211-51a6.2, smoc1, sb:cb252) in key biological processes that included cell survival/apoptosis, ECM-cytoskeleton signaling, and heparan sulfate proteoglycan binding, Conclusion Our results suggest a key role for miR-29b and miR-223 in zebrafish regeneration. The identification of miRNA regulation in a zebrafish injury model provides a framework for future studies in which to investigate not only the cellular processes required for CNS regeneration, but also how these mechanisms might be regulated to promote successful repair and return of function in the injured mammalian brain. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1772-1) contains supplementary material, which is available to authorized users.
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Neill T, Schaefer L, Iozzo RV. Decoding the Matrix: Instructive Roles of Proteoglycan Receptors. Biochemistry 2015; 54:4583-98. [PMID: 26177309 DOI: 10.1021/acs.biochem.5b00653] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The extracellular matrix is a dynamic repository harboring instructive cues that embody substantial regulatory dominance over many evolutionarily conserved intracellular activities, including proliferation, apoptosis, migration, motility, and autophagy. The matrix also coordinates and parses hierarchical information, such as angiogenesis, tumorigenesis, and immunological responses, typically providing the critical determinants driving each outcome. We provide the first comprehensive review focused on proteoglycan receptors, that is, signaling transmembrane proteins that use secreted proteoglycans as ligands, in addition to their natural ligands. The majority of these receptors belong to an exclusive subset of receptor tyrosine kinases and assorted cell surface receptors that specifically bind, transduce, and modulate fundamental cellular processes following interactions with proteoglycans. The class of small leucine-rich proteoglycans is the most studied so far and constitutes the best understood example of proteoglycan-receptor interactions. Decorin and biglycan evoke autophagy and immunological responses that deter, suppress, or exacerbate pathological conditions such as tumorigenesis, angiogenesis, and chronic inflammatory disease. Basement membrane-associated heparan sulfate proteoglycans (perlecan, agrin, and collagen XVIII) represent a unique cohort and provide proteolytically cleaved bioactive fragments for modulating cellular behavior. The receptors that bind the genuinely multifactorial and multivalent proteoglycans represent a nexus in understanding basic biological pathways and open new avenues for therapeutic and pharmacological intervention.
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Affiliation(s)
- Thomas Neill
- †Department of Pathology, Anatomy and Cell Biology and Cancer Cell Biology and Signaling Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Liliana Schaefer
- ‡Department of Pharmacology, Goethe University, 60590 Frankfurt, Germany
| | - Renato V Iozzo
- †Department of Pathology, Anatomy and Cell Biology and Cancer Cell Biology and Signaling Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
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26
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Regulation of cough by neuronal Na(+)-K(+) ATPases. Curr Opin Pharmacol 2015; 22:140-5. [PMID: 26048736 DOI: 10.1016/j.coph.2015.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 01/10/2023]
Abstract
The Na(+)-K(+) ATPases play an essential role in establishing the sodium gradients in excitable cells. Multiple isoforms of the sodium pumps have been identified, with tissue and cell specific expression patterns. Because the vagal afferent nerves regulating cough must be activated at sustained high frequencies of action potential patterning to achieve cough initiation thresholds, it is a certainty that sodium pump function is essential to maintaining cough reflex sensitivities in health and in disease. The mechanisms by which Na(+)-K(+) ATPases regulate bronchopulmonary vagal afferent nerve excitability are reviewed as are potential therapeutic strategies targeting the sodium pumps in cough.
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Talsma AD, Chaves JF, LaMonaca A, Wieczorek ED, Palladino MJ. Genome-wide screen for modifiers of Na (+) /K (+) ATPase alleles identifies critical genetic loci. Mol Brain 2014; 7:89. [PMID: 25476251 PMCID: PMC4302446 DOI: 10.1186/s13041-014-0089-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/20/2014] [Indexed: 12/22/2022] Open
Abstract
Background Mutations affecting the Na+/ K+ATPase (a.k.a. the sodium-potassium pump) genes cause conditional locomotor phenotypes in flies and three distinct complex neurological diseases in humans. More than 50 mutations have been identified affecting the human ATP1A2 and ATP1A3 genes that are known to cause rapid-onset Dystonia Parkinsonism, familial hemiplegic migraine, alternating hemiplegia of childhood, and variants of familial hemiplegic migraine with neurological complications including seizures and various mood disorders. In flies, mutations affecting the ATPalpha gene have dramatic phenotypes including altered longevity, neural dysfunction, neurodegeneration, myodegeneration, and striking locomotor impairment. Locomotor defects can manifest as conditional bang-sensitive (BS) or temperature-sensitive (TS) paralysis: phenotypes well-suited for genetic screening. Results We performed a genome-wide deficiency screen using three distinct missense alleles of ATPalpha and conditional locomotor function assays to identify novel modifier loci. A secondary screen confirmed allele-specificity of the interactions and many of the interactions were mapped to single genes and subsequently validated. We successfully identified 64 modifier loci and used classical mutations and RNAi to confirm 50 single gene interactions. The genes identified include those with known function, several with unknown function or that were otherwise uncharacterized, and many loci with no described association with locomotor or Na+/K+ ATPase function. Conclusions We used an unbiased genome-wide screen to find regions of the genome containing elements important for genetic modulation of ATPalpha dysfunction. We have identified many critical regions and narrowed several of these to single genes. These data demonstrate there are many loci capable of modifying ATPalpha dysfunction, which may provide the basis for modifying migraine, locomotor and seizure dysfunction in animals. Electronic supplementary material The online version of this article (doi:10.1186/s13041-014-0089-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aaron D Talsma
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA. .,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA.
| | - John F Chaves
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA. .,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA.
| | - Alexandra LaMonaca
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA. .,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA.
| | - Emily D Wieczorek
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA. .,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA.
| | - Michael J Palladino
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA. .,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, BST3 7042, Pittsburgh, PA, 15261, USA.
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Sonderegger P, Matsumoto-Miyai K. Activity-controlled proteolytic cleavage at the synapse. Trends Neurosci 2014; 37:413-23. [PMID: 24969462 DOI: 10.1016/j.tins.2014.05.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 12/31/2022]
Abstract
Activity-controlled enzymatic cleavage of proteins on the surface of synaptic membranes or in the synaptic or perisynaptic interstitial compartment represents a direct way to regulate synaptic structure, function, and number. Extracellular proteolysis at synapses was initially understood to be plasticity enabling by freeing synapses from the constraints provided by the extracellular matrix. However, recent observations indicate that at least part of the extracellular protein cleavage results in activation of previously cryptic functions that regulate adaptive changes of synapses and neuronal circuits. Here, we focus on peptidases with distinct localization and function at synapses combined with regulation by neuronal and synaptic activity, and evaluate their function in the context of developmental and/or adult synaptic plasticity.
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Affiliation(s)
- Peter Sonderegger
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Kazumasa Matsumoto-Miyai
- Department of Neurophysiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, Akita 010-8543, Japan; Kansai University of Nursing and Health Sciences, 1456-4 Shizuki, Awaji, Hyogo 656-2131, Japan
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29
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Tsilibary E, Tzinia A, Radenovic L, Stamenkovic V, Lebitko T, Mucha M, Pawlak R, Frischknecht R, Kaczmarek L. Neural ECM proteases in learning and synaptic plasticity. PROGRESS IN BRAIN RESEARCH 2014; 214:135-57. [PMID: 25410356 DOI: 10.1016/b978-0-444-63486-3.00006-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent studies implicate extracellular proteases in synaptic plasticity, learning, and memory. The data are especially strong for such serine proteases as thrombin, tissue plasminogen activator, neurotrypsin, and neuropsin as well as matrix metalloproteinases, MMP-9 in particular. The role of those enzymes in the aforementioned phenomena is supported by the experimental results on the expression patterns (at the gene expression and protein and enzymatic activity levels) and functional studies, including knockout mice, specific inhibitors, etc. Counterintuitively, the studies have shown that the extracellular proteolysis is not responsible mainly for an overall degradation of the extracellular matrix (ECM) and loosening perisynaptic structures, but rather allows for releasing signaling molecules from the ECM, transsynaptic proteins, and latent form of growth factors. Notably, there are also indications implying those enzymes in the major neuropsychiatric disorders, probably by contributing to synaptic aberrations underlying such diseases as schizophrenia, bipolar, autism spectrum disorders, and drug addiction.
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Affiliation(s)
- Effie Tsilibary
- Institute of Biosciences and Applications, NCSR "Demokritos", Athens, Greece
| | - Athina Tzinia
- Institute of Biosciences and Applications, NCSR "Demokritos", Athens, Greece
| | - Lidija Radenovic
- Center for Laser Microscopy, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Vera Stamenkovic
- Center for Laser Microscopy, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Tomasz Lebitko
- Department of Molecular and Cellular Neurobiology, Nencki Institute, Warsaw, Poland
| | | | | | - Renato Frischknecht
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Leszek Kaczmarek
- Department of Molecular and Cellular Neurobiology, Nencki Institute, Warsaw, Poland.
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30
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Morawski M, Filippov M, Tzinia A, Tsilibary E, Vargova L. ECM in brain aging and dementia. PROGRESS IN BRAIN RESEARCH 2014; 214:207-27. [PMID: 25410360 DOI: 10.1016/b978-0-444-63486-3.00010-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
An essential component of the brain extracellular space is the extracellular matrix contributing to the spatial assembly of cells by binding cell-surface adhesion molecules, supporting cell migration, differentiation, and tissue development. The most interesting and complex functions of the central nervous system are the abilities to encode new information (learning) and to store this information (memory). The creation of perineuronal nets, consisting mostly of chondroitin sulfate proteoglycans, stabilizes the synapses and memory trails and forms protective shields against neurodegenerative processes but terminates plasticity and the potential for recovery of the tissue. Age-related changes in the extracellular matrix composition and the extracellular space volume and permissivity are major determinants of the onset and development of the most common neurodegenerative disorder, Alzheimer's disease. In this regard, heparan sulfate proteoglycans, involved in amyloid clearance from the brain, play an important role in Alzheimer's disease and other types of neurodegeneration. Additional key players in the modification of the extracellular matrix are matrix metalloproteinases. Recent studies show that the extracellular matrix and matrix metalloproteinases are important regulators of plasticity, learning, and memory and might be involved in different neurological disorders like epilepsy, schizophrenia, addiction, and dementia. The identification of molecules and mechanisms that modulate these processes is crucial for the understanding of brain function and dysfunction and for the design of new therapeutic approaches targeting the molecular mechanism underlying these neurological disorders.
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Affiliation(s)
- Markus Morawski
- University of Leipzig, EU-ESF Transnational Junior Research Group "MESCAMP", Paul Flechsig Institute for Brain Research, Leipzig, Germany.
| | - Mikhail Filippov
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Athina Tzinia
- NCSR "Demokritos", Institute of Biosciences and Applications, Athens, Greece
| | - Effie Tsilibary
- NCSR "Demokritos", Institute of Biosciences and Applications, Athens, Greece
| | - Lydia Vargova
- Charles University, 2nd Faculty of Medicine, Department of Neuroscience, Prague, Czech Republic; Institute of Experimental Medicine AS CR, v.v.i., Department of Neuroscience, Prague, Czech Republic
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31
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Na+/K+-ATPase is a new interacting partner for the neuronal glycine transporter GlyT2 that downregulates its expression in vitro and in vivo. J Neurosci 2013; 33:14269-81. [PMID: 23986260 DOI: 10.1523/jneurosci.1532-13.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The neuronal glycine transporter GlyT2 plays a fundamental role in the glycinergic neurotransmission by recycling the neurotransmitter to the presynaptic terminal. GlyT2 is the main supplier of glycine for vesicle refilling, a process that is absolutely necessary to preserve quantal glycine content in synaptic vesicles. Alterations in GlyT2 activity modify glycinergic neurotransmission and may underlie several neuromuscular disorders, such as hyperekplexia, myoclonus, dystonia, and epilepsy. Indeed, mutations in the gene encoding GlyT2 are the main presynaptic cause of hyperekplexia in humans and produce congenital muscular dystonia type 2 (CMD2) in Belgian Blue cattle. GlyT2 function is strictly coupled to the sodium electrochemical gradient actively generated by the Na+/K+-ATPase (NKA). GlyT2 cotransports 3Na+/Cl-/glycine generating large rises of Na+ inside the presynaptic terminal that must be efficiently reduced by the NKA to preserve Na+ homeostasis. In this work, we have used high-throughput mass spectrometry to identify proteins interacting with GlyT2 in the CNS. NKA was detected as a putative candidate and through reciprocal coimmunoprecipitations and immunocytochemistry analyses the association between GlyT2 and NKA was confirmed. NKA mainly interacts with the raft-associated active pool of GlyT2, and low and high levels of the specific NKA ligand ouabain modulate the endocytosis and total expression of GlyT2 in neurons. The ouabain-mediated downregulation of GlyT2 also occurs in vivo in two different systems: zebrafish embryos and adult rats, indicating that this NKA-mediated regulatory mechanism is evolutionarily conserved and may play a relevant role in the physiological control of inhibitory glycinergic neurotransmission.
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32
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Mitsui S, Osako Y, Yuri K. Mental retardation-related protease, motopsin (prss12), binds to the BRICHOS domain of the integral membrane protein 2a. Cell Biol Int 2013; 38:117-23. [PMID: 23955961 DOI: 10.1002/cbin.10164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/02/2013] [Indexed: 11/06/2022]
Abstract
Motopsin (prss12), a mosaic serine protease secreted by neuronal cells, is believed to be important for cognitive function, as the loss of its function causes severe nonsyndromic mental retardation. To understand the molecular role of motopsin, we identified the integral membrane protein 2a (Itm2a) as a motopsin-interacting protein using a yeast two-hybrid system. A pull-down assay showed that the BRICHOS domain of Itm2a was essential for this interaction. Motopsin and Itm2a co-localized in COS cells and in cultured neurons when transiently expressed in these cells. Both proteins were co-immunoprecipitated from lysates of these transfected COS cells. Itm2a was strongly detected in a brain lysate prepared between postnatal day 0 and 10, during which period motopsin protein was also enriched in the brain. Immunohistochemistry detected Itm2a as patchy spots along endothelial cells of brain capillaries (which also expressed myosin II regulatory light chain [RLC]), and on glial fibrillary acidic protein (GFAP)-positive processes in the developing cerebral cortex. The data raise the possibility that secreted motopsin interacts with endothelial cells in the developing brain.
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Affiliation(s)
- Shinichi Mitsui
- Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, Showa, Maebashi, 371-8514, Japan
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33
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Mitsui S, Hidaka C, Furihata M, Osako Y, Yuri K. A mental retardation gene, motopsin/prss12, modulates cell morphology by interaction with seizure-related gene 6. Biochem Biophys Res Commun 2013; 436:638-44. [DOI: 10.1016/j.bbrc.2013.04.112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 04/27/2013] [Indexed: 10/26/2022]
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Patel TR, Butler G, McFarlane A, Xie I, Overall CM, Stetefeld J. Site specific cleavage mediated by MMPs regulates function of agrin. PLoS One 2012; 7:e43669. [PMID: 22984437 PMCID: PMC3439447 DOI: 10.1371/journal.pone.0043669] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 07/23/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Agrin is the key inducer of postsynaptic differentiations at the neuromuscular junction. The multidomain heparan sulfate proteoglycan is mediating via its N-terminal segment the interaction with laminin, whereas the C-terminal portion is responsible for Dystroglycan binding and clustering of the Acetylcholine receptor. Matrix metalloproteinases (MMP) are known to play essential roles in matrix remodeling, degradation and regulation of extracellular signaling networks. PRINCIPAL FINDINGS Site-specific processing of Agrin provides key insight into regulatory effects of Matrix metalloproteinases (MMPs). Here, we present a detailed study of agrin processing by different MMPs together with a molecular understanding of binding and cleavage at both terminal fragments. The data suggest for a regulatory effect of MMP cleavage at particularly important functional sites of agrin. Cleave of agrin abolishes the agrin-laminin complex formation and the Acetylcholine receptor clustering at the neuromuscular junction. CONCLUSION/SIGNIFICANCE Agrin is a target of specific MMP processing resulting in agrin subfragments with different regulatory activities. MMP processing is a powerful tool to regulate extracellular signaling networks.
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Affiliation(s)
- Trushar R. Patel
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Georgina Butler
- Centre for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ainsley McFarlane
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Irene Xie
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Christopher M. Overall
- Centre for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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35
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Singhal N, Martin PT. Role of extracellular matrix proteins and their receptors in the development of the vertebrate neuromuscular junction. Dev Neurobiol 2012; 71:982-1005. [PMID: 21766463 DOI: 10.1002/dneu.20953] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vertebrate neuromuscular junction (NMJ) remains the best-studied model for understanding the mechanisms involved in synaptogenesis, due to its relatively large size, its simplicity of patterning, and its unparalleled experimental accessibility. During neuromuscular development, each skeletal myofiber secretes and deposits around its extracellular surface an assemblage of extracellular matrix (ECM) proteins that ultimately form a basal lamina. This is also the case at the NMJ, where the motor nerve contributes additional factors. Before most of the current molecular components were known, it was clear that the synaptic ECM of adult skeletal muscles was unique in composition and contained factors sufficient to induce the differentiation of both pre- and postsynaptic membranes. Biochemical, genetic, and microscopy studies have confirmed that agrin, laminin (221, 421, and 521), collagen IV (α3-α6), collagen XIII, perlecan, and the ColQ-bound form of acetylcholinesterase are all synaptic ECM proteins with important roles in neuromuscular development. The roles of their many potential receptors and/or binding proteins have been more difficult to assess at the genetic level due to the complexity of membrane interactions with these large proteins, but roles for MuSK-LRP4 in agrin signaling and for integrins, dystroglycan, and voltage-gated calcium channels in laminin-dependent phenotypes have been identified. Synaptic ECM proteins and their receptors are involved in almost all aspects of synaptic development, including synaptic initiation, topography, ultrastructure, maturation, stability, and transmission.
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Affiliation(s)
- Neha Singhal
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, Ohio State University College of Medicine, Columbus, Ohio 43205, USA
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36
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Maselli RA, Fernandez JM, Arredondo J, Navarro C, Ngo M, Beeson D, Cagney Ó, Williams DC, Wollmann RL, Yarov-Yarovoy V, Ferns MJ. LG2 agrin mutation causing severe congenital myasthenic syndrome mimics functional characteristics of non-neural (z-) agrin. Hum Genet 2012; 131:1123-35. [PMID: 22205389 PMCID: PMC4795461 DOI: 10.1007/s00439-011-1132-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/11/2011] [Indexed: 10/14/2022]
Abstract
We describe a severe form of congenital myasthenic syndrome (CMS) caused by two heteroallelic mutations: a nonsense and a missense mutation in the gene encoding agrin (AGRN). The identified mutations, Q353X and V1727F, are located at the N-terminal and at the second laminin G-like (LG2) domain of agrin, respectively. A motor-point muscle biopsy demonstrated severe disruption of the architecture of the neuromuscular junction (NMJ), including: dispersion and fragmentation of endplate areas with normal expression of acetylcholinesterase; simplification of postsynaptic membranes; pronounced reduction of the axon terminal size; widening of the primary synaptic cleft; and, collection of membranous debris material in the primary synaptic cleft and in the subsynaptic cytoplasm. Expression studies in heterologous cells revealed that the Q353X mutation abolished expression of full-length agrin. Moreover, the V1727F mutation decreased agrin-induced clustering of the acetylcholine receptor (AChR) in cultured C2 muscle cells by >100-fold, and phosphorylation of the MuSK receptor and AChR beta subunit by ~tenfold. Surprisingly, the V1727F mutant also displayed increased binding to α-dystroglycan but decreased binding to a neural (z+) agrin-specific antibody. Our findings demonstrate that agrin mutations can associate with a severe form of CMS and cause profound distortion of the architecture and function of the NMJ. The impaired ability of V1727F agrin to activate MuSK and cluster AChRs, together with its increased affinity to α-dystroglycan, mimics non-neural (z-) agrin and are important determinants of the pathogenesis of the disease.
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MESH Headings
- Acetylcholinesterase/metabolism
- Adult
- Agrin/chemistry
- Agrin/genetics
- Agrin/metabolism
- Base Sequence
- Cell Line
- Codon, Nonsense
- Dystroglycans/metabolism
- Female
- HEK293 Cells
- Humans
- Male
- Models, Molecular
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Mutation, Missense
- Myasthenic Syndromes, Congenital/genetics
- Myasthenic Syndromes, Congenital/metabolism
- Neuromuscular Junction/metabolism
- Neuromuscular Junction/pathology
- Pedigree
- Receptors, Cholinergic/genetics
- Receptors, Cholinergic/metabolism
- Sequence Analysis, DNA
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Affiliation(s)
- Ricardo A. Maselli
- Department of Neurology, University of California Davis, Davis, California, 95616 USA
| | - Jose M. Fernandez
- Service of Clinical Neurophysiology. University Hospital of Vigo, Vigo (Pontevedra), Spain
| | - Juan Arredondo
- Department of Neurology, University of California Davis, Davis, California, 95616 USA
| | - Carmen Navarro
- Department of Pathology, University Hospital of Vigo and CIBERER (Centro de Investigacion Biomedica en Red en Enfermedades Raras), Vigo (Pontevedra), Spain
| | - Maian Ngo
- Department of Neurology, University of California Davis, Davis, California, 95616 USA
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Órla Cagney
- Department of Neurology, University of California Davis, Davis, California, 95616 USA
| | - D. Colette Williams
- Veterinary Medical Teaching Hospital, University of California Davis, Davis, California, 95616, USA
| | - Robert L. Wollmann
- Department of Pathology, University of Chicago, Chicago, Illinois, 60637, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California 95616, USA
| | - Michael J Ferns
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California 95616, USA
- Department of Anesthesiology, University of California Davis, Davis, California 95616, USA
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Mukhina IV, Korotchenko SA, Dityatev AE. Extracellular matrix molecules, their receptors, and extracellular proteases as synaptic plasticity modulators. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412020055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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38
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Kirshenbaum GS, Clapcote SJ, Petersen J, Vilsen B, Ralph MR, Roder JC. Genetic suppression of agrin reduces mania-like behavior in Na+ , K+ -ATPase α3 mutant mice. GENES BRAIN AND BEHAVIOR 2012; 11:436-43. [PMID: 22520507 DOI: 10.1111/j.1601-183x.2012.00800.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Myshkin mice heterozygous for an inactivating mutation in the neuron-specific Na(+) ,K(+) -ATPase α3 isoform show behavior analogous to mania, including an abnormal endogenous circadian period. Agrin is a proteoglycan implicated as a regulator of synapses that has been proposed to inhibit activity of Na(+) ,K(+) -ATPase α3. We examined whether the mania-related behavior of Myshkin mice could be rescued by a reduction in the expression of agrin through genetic knockout. The suppression of agrin reduced hyperambulation and holeboard exploration, restored anxiety-like behavior (or reduced risk-taking behavior), improved prepulse inhibition and shortened the circadian period. Hence, agrin is important for regulating mania-like behavior and circadian rhythms. In Myshkin mice, the suppression of agrin increased brain Na(+) ,K(+) -ATPase activity by 11 ± 4%, whereas no effect on Na(+) ,K(+) -ATPase activity was detected when agrin was suppressed in mice without the Myshkin mutation. These results introduce agrin as a potential therapeutic target for the treatment of mania and other neurological disorders associated with reduced Na(+) ,K(+) -ATPase activity and neuronal hyperexcitability.
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Affiliation(s)
- G S Kirshenbaum
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
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39
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Agrin-signaling is necessary for the integration of newly generated neurons in the adult olfactory bulb. J Neurosci 2012; 32:3759-64. [PMID: 22423096 DOI: 10.1523/jneurosci.4906-11.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In the adult forebrain, new interneurons are continuously generated and integrated into the existing circuitry of the olfactory bulb (OB). In an attempt to identify signals that regulate this synaptic integration process, we found strong expression of agrin in adult generated neuronal precursors that arrive in the olfactory bulb after their generation in the subventricular zone. While the agrin receptor components MuSK and Lrp4 were below detection level in neuron populations that represent synaptic targets for the new interneurons, the alternative receptor α3-Na(+)K(+)-ATPase was strongly expressed in mitral cells. Using a transplantation approach, we demonstrate that agrin-deficient interneuron precursors migrate correctly into the OB. However, in contrast to wild-type neurons, which form synapses and survive for prolonged periods, mutant neurons do not mature and are rapidly eliminated. Using in vivo brain electroporation of the olfactory system, we show that the transmembrane form of agrin alone is sufficient to mediate integration and demonstrate that excess transmembrane agrin increases the number of dendritic spines. Last, we provide in vivo evidence that an interaction between agrin and α3-Na(+)K(+)-ATPase is of functional importance in this system.
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40
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Wang H, Imamura Y, Matsumoto N, Wang H, Ogura H, Shimazu T, Seiyama A. Novel sonomicrometry of ex vivo diaphragm after phrenic nerve injury: Role of matrix metalloproteinases. Synapse 2012; 66:677-85. [PMID: 22389130 DOI: 10.1002/syn.21552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 12/21/2022]
Abstract
Extracellular matrix (ECM) proteins and their proteolytic enzymes, matrix metalloproteinases (MMPs), implicate in neuromuscular junctions (NMJs) function during development. However, their pathophysiological mechanisms in the diaphragm remain obscure, because a well-characterized ex vivo experimental system has still been lacking. In the study, we aim to develop a novel ex vivo method of sonomicrometry and evaluate validity of the method with a mouse diaphragm twitch after phrenic nerve injury. In an ex vivo experiment using phrenic nerve-injured mice, diaphragm twitch during electrical pulse stimulation of phrenic nerve was transiently suppressed on day 1. Recombinant MMPs administered in recording solution exerted dose-responsive suppression on the diaphragm twitch in normal mice tissue. Furthermore, gelatinolytic and immunoblot experiments were performed to evaluate MMPs' involvement and NMJs' insults. After nerve injury, (1) in vivo levels of MMPs were transiently upregulated at day 1 and (2) expressions of ECM proteins, agrin (nicotinic acetylcholine receptor stabilizer) and laminin, were transiently reduced at day 1 in the diaphragm. These alterations were cancelled by preinjection of the MMP inhibitor. In conclusion, MMPs hamper NMJ synaptic function in association with the impairment of ECM milieu. Our novel experimental method using ex vivo sonomicrometry is necessary for examining the molecular pathophysiolgy for the dysfunction of NMJs in the diaphragm.
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Affiliation(s)
- Huan Wang
- Department of Molecular Oncology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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41
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The role of agrin in synaptic development, plasticity and signaling in the central nervous system. Neurochem Int 2012; 61:848-53. [PMID: 22414531 DOI: 10.1016/j.neuint.2012.02.028] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 02/03/2012] [Accepted: 02/25/2012] [Indexed: 01/13/2023]
Abstract
Development of the neuromuscular junction (NMJ) requires secretion of specific isoforms of the proteoglycan agrin by motor neurons. Secreted agrin is widely expressed in the basal lamina of various tissues, whereas a transmembrane form is highly expressed in the brain. Expression in the brain is greatest during the period of synaptogenesis, but remains high in regions of the adult brain that show extensive synaptic plasticity. The well-established role of agrin in NMJ development and its presence in the brain elicited investigations of its possible role in synaptogenesis in the brain. Initial studies on the embryonic brain and neuronal cultures of agrin-null mice did not reveal any defects in synaptogenesis. However, subsequent studies in culture demonstrated inhibition of synaptogenesis by agrin antisense oligonucleotides or agrin siRNA. More recently, a substantial loss of excitatory synapses was found in the brains of transgenic adult mice that lacked agrin expression everywhere but in motor neurons. The mechanisms by which agrin influences synapse formation, maintenance and plasticity may include enhancement of excitatory synaptic signaling, activation of the "muscle-specific" receptor tyrosine kinase (MuSK) and positive regulation of dendritic filopodia. In this article I will review the evidence that agrin regulates synapse development, plasticity and signaling in the brain and discuss the evidence for the proposed mechanisms.
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42
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Mohanty BK, Gupta BL. A marked animal-vegetal polarity in the localization of Na(+),K(+) -ATPase activity and its down-regulation following progesterone-induced maturation. Mol Reprod Dev 2011; 79:138-60. [PMID: 22213374 DOI: 10.1002/mrd.22012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/22/2011] [Indexed: 01/01/2023]
Abstract
The stage-VI Xenopus oocyte has a very distinct animal-vegetal polarity with structural and functional asymmetry. In this study, we show the expression and distribution pattern of Na(+),K(+) -ATPase in stage-VI oocytes, and its changes following progesterone-induced maturation. Using enzyme-specific electron microscopy phosphatase histochemistry, [(3) H]-ouabain autoradiography, and immunofluorescence cytochemistry at light microscopic level, we find that Na(+),K(+) -ATPase activity is mainly confined to the animal hemisphere. Electron microscopy histochemical results also suggest that polarized distribution of Na(+),K(+) -ATPase activity persists following progesterone-induced maturation, and it becomes gradually more polarized towards the animal pole. The time course following progesterone-induced maturation suggests that there is an initial up-regulation and then gradual down-regulation of Na(+),K(+) -ATPase activity leading to germinal vesicle breakdown (GVBD). By GVBD, the Na(+),K(+) -ATPase activity is completely down-regulated due to endocytotic removal of pump molecules from the plasma membrane into the sub-cortical region of the oocyte. This study provides the first direct evidence for a marked asymmetric localization of Na(+),K(+) -ATPase activity in any vertebrate oocyte. Here, we propose that such asymmetry in Na(+),K(+) -ATPase activity in stage-VI oocytes, and their down-regulation following progesterone-induced maturation, is likely to have a role in the active state of the germinal vesicle in stage-VI oocytes and chromosomal condensation after GVBD.
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43
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Akimova OA, Van Huysse J, Tremblay J, Orlov SN. Low efficiency of functional translation of ouabain-resistant α2-Na(+),K(+)-ATPase mRNA in C7-MDCK epithelial cells. Can J Physiol Pharmacol 2011; 90:83-8. [PMID: 22188474 DOI: 10.1139/y11-113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na(+),K(+)-ATPase is a heterodimer consisting of catalytic α1-α4 and regulatory β1-β3 subunits. Recently, we reported that transfection with ouabain-resistant α1R-Na(+),K(+)-ATPase rescues renal epithelial C7-MDCK cells exclusively expressing the ouabain-sensitive α1S-isoform from the cytotoxic action of ouabain. To explore the role of α2 subunit in ion transport and cytotoxic action of ouabain, we compared the effect of ouabain on K(+) ((86)Rb) influx and the survival of ouabain-treated C7-MDCK cells stably transfected with α1R- and α2R-Na(+),K(+)-ATPase. α2R mRNA in transfected cells was ∼8-fold more abundant than α1R mRNA, whereas immunoreactive α2R protein content was 5-fold lower than endogenous α1S protein. A concentration of 10 µmol/L ouabain led to complete inhibition of (86)Rb influx both in mock- and α2R-transfected cells, whereas maximal inhibition of (86)Rb influx in α1R-transfectd cells was observed at 1000 µmol/L ouabain. In contrast to the massive death of mock- and α2R-transfected cells exposed to 3 µmol/L ouabain , α1R-cells survived after 24 h incubation with 1000 µmol/L ouabain. Thus, our results show that unlike α1R, the presence of α2R-Na(+),K(+)-ATPase subunit mRNA and immunoreactive protein does not contribute to Na(+)/K(+) pump activity, and does not rescue C7-MDCK cells from the cytotoxic action of ouabain. Our results also suggest that the lack of impact of transfected α2-Na(+),K(+)-ATPase on Na(+)/K(+) pump activity and cell survival can be attributed to the low efficiency of its translation and (or) delivery to the plasma membrane of renal epithelial cells.
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Affiliation(s)
- Olga A Akimova
- Research Centre, Centre hospitalier de l'Université de Montréal (CRCHUM) - Technopôle Angus, 2901 Rachel East, Montreal, QC H1W 4A4, Canada
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Rimer M. Emerging roles for MAP kinases in agrin signaling. Commun Integr Biol 2011; 4:143-6. [PMID: 21655426 DOI: 10.4161/cib.4.2.14357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 11/19/2022] Open
Abstract
Information between neurons and the target cells they innervate passes through sites of functional contact called synapses. How synapses form and are altered by sensory or cognitive experience is central to understand nervous system function. Studies of synapse formation and plasticity have concentrated on a few "model" synapses. The vertebrate neuromuscular junction (NMJ), the synapse between a motoneuron in the spinal cord and a skeletal muscle fiber, is one such model synapse. The extracellular matrix proteoglycan agrin plays an essential organizing role at the NMJ. Agrin is also present at some synapses in the brain and in other organs in the periphery, but its function outside the NMJ is unclear. The core signaling pathway for agrin at the NMJ, which is still incompletely defined, includes molecules specifically involved in this cascade and molecules used in other signaling pathways in many cells. Mitogen-activated protein kinases (MAPKs) are evolutionarily conserved components of intracellular signaling modules that control a myriad of cellular processes. This article reviews emerging evidence that suggests that MAPKs are involved in agrin signaling at the NMJ and in the putative functions of agrin in the formation of a subset of synapses in the brain.
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Affiliation(s)
- Mendell Rimer
- Department of Neuroscience & Experimental Therapeutics; College of Medicine; Texas A&M Health Science Center; College Station, TX USA
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45
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Patel TR, Meier M, Li J, Morris G, Rowe AJ, Stetefeld J. T-shaped arrangement of the recombinant agrin G3-IgG Fc protein. Protein Sci 2011; 20:931-40. [PMID: 21448912 PMCID: PMC3104224 DOI: 10.1002/pro.628] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/14/2011] [Accepted: 03/16/2011] [Indexed: 12/12/2022]
Abstract
Agrin is a large heparin sulphate proteoglycan with multiple domains, which is located in the extracellular matrix. The C-terminal G3 domain of agrin is functionally one of the most important domains. It harbors an α-dystroglycan binding site and carries out acetylcholine receptor clustering activities. In the present study, we have fused the G3 domain of agrin to an IgG Fc domain to produce a G3-Fc fusion protein that we intend to use as a tool to investigate new binding partners of agrin. As a first step of the study, we have characterized the recombinant fusion protein using a multidisciplinary approach using dynamic light scattering, analytical ultracentrifugation and small angle X-ray scattering (SAXS). Interestingly, our SAXS analysis using the high-resolution structures of G3 and Fc domain as models indicates that the G3-Fc protein forms a T-shaped molecule with the G3 domains extruding perpendicularly from the Fc scaffold. To validate our models, we have used the program HYDROPRO to calculate the hydrodynamic properties of the solution models. The calculated values are in excellent agreement with those determined experimentally.
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Affiliation(s)
- Trushar R Patel
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T2N2, Canada
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46
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Li KC, Zhang FX, Li CL, Wang F, Yu MY, Zhong YQ, Zhang KH, Lu YJ, Wang Q, Ma XL, Yao JR, Wang JY, Lin LB, Han M, Zhang YQ, Kuner R, Xiao HS, Bao L, Gao X, Zhang X. Follistatin-like 1 suppresses sensory afferent transmission by activating Na+,K+-ATPase. Neuron 2011; 69:974-87. [PMID: 21382556 DOI: 10.1016/j.neuron.2011.01.022] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2010] [Indexed: 01/09/2023]
Abstract
Excitatory synaptic transmission is modulated by inhibitory neurotransmitters and neuromodulators. We found that the synaptic transmission of somatic sensory afferents can be rapidly regulated by a presynaptically secreted protein, follistatin-like 1 (FSTL1), which serves as a direct activator of Na(+),K(+)-ATPase (NKA). The FSTL1 protein is highly expressed in small-diameter neurons of the dorsal root ganglion (DRG). It is transported to axon terminals via small translucent vesicles and secreted in both spontaneous and depolarization-induced manners. Biochemical assays showed that FSTL1 binds to the α1 subunit of NKA and elevates NKA activity. Extracellular FSTL1 induced membrane hyperpolarization in cultured cells and inhibited afferent synaptic transmission in spinal cord slices by activating NKA. Genetic deletion of FSTL1 in small DRG neurons of mice resulted in enhanced afferent synaptic transmission and sensory hypersensitivity, which could be reduced by intrathecally applied FSTL1 protein. Thus, FSTL1-dependent activation of NKA regulates the threshold of somatic sensation.
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Affiliation(s)
- Kai-Cheng Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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Bøttger P, Tracz Z, Heuck A, Nissen P, Romero-Ramos M, Lykke-Hartmann K. Distribution of Na/K-ATPase alpha 3 isoform, a sodium-potassium P-type pump associated with rapid-onset of dystonia parkinsonism (RDP) in the adult mouse brain. J Comp Neurol 2011; 519:376-404. [PMID: 21165980 DOI: 10.1002/cne.22524] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Na(+)/K(+)-ATPase1 alpha subunit 3 (ATP1α(3)) is one of many essential components that maintain the sodium and potassium gradients across the plasma membrane in animal cells. Mutations in the ATP1A3 gene cause rapid-onset of dystonia parkinsonism (RDP), a rare movement disorder characterized by sudden onset of dystonic spasms and slowness of movement. To achieve a better understanding of the pathophysiology of the disease, we used immunohistochemical approaches to describe the regional and cellular distribution of ATP1α(3) in the adult mouse brain. Our results show that localization of ATP1α(3) is restricted to neurons, and it is expressed mostly in projections (fibers and punctuates), but cell body expression is also observed. We found high expression of ATP1α(3) in GABAergic neurons in all nuclei of the basal ganglia (striatum, globus pallidus, subthalamic nucleus, and substantia nigra), which is a key circuitry in the fine movement control. Several thalamic nuclei structures harboring connections to and from the cortex expressed high levels of the ATP1α(3) isoform. Other structures with high expression of ATP1α(3) included cerebellum, red nucleus, and several areas of the pons (reticulotegmental nucleus of pons). We also found high expression of ATP1α(3) in projections and cell bodies in hippocampus; most of these ATP1α(3)-positive cell bodies showed colocalization to GABAergic neurons. ATP1α(3) expression was not significant in the dopaminergic cells of substantia nigra. In conclusion, and based on our data, ATP1α(3) is widely expressed in neuronal populations but mainly in GABAergic neurons in areas and nuclei related to movement control, in agreement with RDP symptoms.
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Affiliation(s)
- Pernille Bøttger
- Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation
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Blom H, Rönnlund D, Scott L, Spicarova Z, Widengren J, Bondar A, Aperia A, Brismar H. Spatial distribution of Na+-K+-ATPase in dendritic spines dissected by nanoscale superresolution STED microscopy. BMC Neurosci 2011; 12:16. [PMID: 21272290 PMCID: PMC3040715 DOI: 10.1186/1471-2202-12-16] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 01/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Na+,K+-ATPase plays an important role for ion homeostasis in virtually all mammalian cells, including neurons. Despite this, there is as yet little known about the isoform specific distribution in neurons. RESULTS With help of superresolving stimulated emission depletion microscopy the spatial distribution of Na+,K+-ATPase in dendritic spines of cultured striatum neurons have been dissected. The found compartmentalized distribution provides a strong evidence for the confinement of neuronal Na+,K+-ATPase (α3 isoform) in the postsynaptic region of the spine. CONCLUSIONS A compartmentalized distribution may have implications for the generation of local sodium gradients within the spine and for the structural and functional interaction between the sodium pump and other synaptic proteins. Superresolution microscopy has thus opened up a new perspective to elucidate the nature of the physiological function, regulation and signaling role of Na+,K+-ATPase from its topological distribution in dendritic spines.
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Affiliation(s)
- Hans Blom
- Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
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Morth JP, Pedersen BP, Buch-Pedersen MJ, Andersen JP, Vilsen B, Palmgren MG, Nissen P. A structural overview of the plasma membrane Na+,K+-ATPase and H+-ATPase ion pumps. Nat Rev Mol Cell Biol 2011; 12:60-70. [PMID: 21179061 DOI: 10.1038/nrm3031] [Citation(s) in RCA: 244] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Plasma membrane ATPases are primary active transporters of cations that maintain steep concentration gradients. The ion gradients and membrane potentials derived from them form the basis for a range of essential cellular processes, in particular Na(+)-dependent and proton-dependent secondary transport systems that are responsible for uptake and extrusion of metabolites and other ions. The ion gradients are also both directly and indirectly used to control pH homeostasis and to regulate cell volume. The plasma membrane H(+)-ATPase maintains a proton gradient in plants and fungi and the Na(+),K(+)-ATPase maintains a Na(+) and K(+) gradient in animal cells. Structural information provides insight into the function of these two distinct but related P-type pumps.
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Affiliation(s)
- J Preben Morth
- Danish National Research Foundation, Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Denmark
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Abstract
The elusiveness of neuropathic pain mechanisms is a major impediment in developing effective clinical treatments. Here we show that peripheral nerve injury decreased agrin expression in the ipsilateral spinal dorsal horn of rats displaying tactile allodynia. SCP1, an acetaminophen analog, suppressed allodynia and promoted agrin upregulation. Preemptive treatment with SCP1 also upregulated agrin, thereby preventing neuropathic pain development. Expression of 50 kDa agrin delivered by adeno-associated virus into the dorsal horn also suppressed allodynia and hyperalgesia. Allodynia suppression was a consequence of serine residue 896/897 phosphorylation of NMDA receptor NR1 subunits in the GABA interneurons of the dorsal horn. Agrin silencing by small interference RNA, administered with either AAV-Ag50 vector or SCP1, blocked allodynia suppression, agrin upregulation, and NR1 phosphorylation. In conclusion, 50 kDa agrin modulates neuropathic pain through NR1 phosphorylation in GABA neurons. This mechanism may open new approaches for treating not only neuropathic pain, but also epilepsy, tremors, and spasticity.
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