101
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LAR-RPTPs: synaptic adhesion molecules that shape synapse development. Trends Cell Biol 2013; 23:465-75. [DOI: 10.1016/j.tcb.2013.07.004] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/07/2013] [Accepted: 07/08/2013] [Indexed: 12/21/2022]
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102
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Wentzel C, Sommer JE, Nair R, Stiefvater A, Sibarita JB, Scheiffele P. mSYD1A, a mammalian synapse-defective-1 protein, regulates synaptogenic signaling and vesicle docking. Neuron 2013; 78:1012-23. [PMID: 23791195 DOI: 10.1016/j.neuron.2013.05.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2013] [Indexed: 10/26/2022]
Abstract
Structure and function of presynaptic terminals are critical for the transmission and processing of neuronal signals. Trans-synaptic signaling systems instruct the differentiation and function of presynaptic release sites, but their downstream mediators are only beginning to be understood. Here, we identify the intracellular mSYD1A (mouse Synapse-Defective-1A) as a regulator of presynaptic function in mice. mSYD1A forms a complex with presynaptic receptor tyrosine phosphatases and controls tethering of synaptic vesicles at synapses. mSYD1A function relies on an intrinsically disordered domain that interacts with multiple structurally unrelated binding partners, including the active zone protein liprin-α2 and nsec1/munc18-1. In mSYD1A knockout mice, synapses assemble in normal numbers but there is a significant reduction in synaptic vesicle docking at the active zone and an impairment of synaptic transmission. Thus, mSYD1A is a regulator of presynaptic release sites at central synapses.
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103
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Song YS, Lee HJ, Prosselkov P, Itohara S, Kim E. Trans-induced cis interaction in the tripartite NGL-1, netrin-G1 and LAR adhesion complex promotes development of excitatory synapses. J Cell Sci 2013; 126:4926-38. [PMID: 23986473 DOI: 10.1242/jcs.129718] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The initial contact between axons and dendrites at early neuronal synapses is mediated by surface adhesion molecules and is thought to induce synaptic maturation through the recruitment of additional synaptic proteins. The initiation of synaptic maturation should be tightly regulated to ensure that synaptic maturation occurs selectively at subcellular sites of axo-dendritic adhesion. However, the underlying mechanism is poorly understood. Here, we report that the initial trans-synaptic adhesion mediated by presynaptic netrin-G1 and postsynaptic NGL-1 (netrin-G1 ligand-1) induces a cis interaction between netrin-G1 and the receptor protein tyrosine phosphatase LAR (leukocyte antigen-related), and that this promotes presynaptic differentiation. We propose that trans-synaptic adhesions at early neuronal synapses trigger recruitment of neighboring adhesion molecules in a cis manner in order to couple initial axo-dendritic adhesion with synaptic differentiation.
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Affiliation(s)
- Yoo Sung Song
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea
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104
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Won H, Mah W, Kim E. Autism spectrum disorder causes, mechanisms, and treatments: focus on neuronal synapses. Front Mol Neurosci 2013; 6:19. [PMID: 23935565 PMCID: PMC3733014 DOI: 10.3389/fnmol.2013.00019] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 12/24/2022] Open
Abstract
Autism spectrum disorder (ASD) is a group of developmental disabilities characterized by impairments in social interaction and communication and restricted and repetitive interests/behaviors. Advances in human genomics have identified a large number of genetic variations associated with ASD. These associations are being rapidly verified by a growing number of studies using a variety of approaches, including mouse genetics. These studies have also identified key mechanisms underlying the pathogenesis of ASD, many of which involve synaptic dysfunctions, and have investigated novel, mechanism-based therapeutic strategies. This review will try to integrate these three key aspects of ASD research: human genetics, animal models, and potential treatments. Continued efforts in this direction should ultimately reveal core mechanisms that account for a larger fraction of ASD cases and identify neural mechanisms associated with specific ASD symptoms, providing important clues to efficient ASD treatment.
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Affiliation(s)
- Hyejung Won
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Won Mah
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeon, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeon, South Korea
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105
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Siddiqui T, Tari P, Connor S, Zhang P, Dobie F, She K, Kawabe H, Wang Y, Brose N, Craig A. An LRRTM4-HSPG Complex Mediates Excitatory Synapse Development on Dentate Gyrus Granule Cells. Neuron 2013; 79:680-95. [DOI: 10.1016/j.neuron.2013.06.029] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 01/24/2023]
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106
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Verpelli C, Galimberti I, Gomez-Mancilla B, Sala C. Molecular basis for prospective pharmacological treatment strategies in intellectual disability syndromes. Dev Neurobiol 2013; 74:197-206. [PMID: 23695997 DOI: 10.1002/dneu.22093] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 03/27/2013] [Accepted: 05/13/2013] [Indexed: 11/07/2022]
Abstract
A number of mutated genes that code for proteins concerned with brain synapse function and circuit formation have been identified in patients affected by intellectual disability (ID) syndromes over the past 15 years. These genes are involved in synapse formation and plasticity, the regulation of dendritic spine morphology, the regulation of the synaptic cytoskeleton, the synthesis and degradation of specific synapse proteins, and the control of correct balance between excitatory and inhibitory synapses. In most of the cases, even mild alterations in synapse morphology, function, and balance give rise to mild or severe IDs. These studies provided a rationale for the development of pharmacological agents that are able to counteract functional synaptic anomalies and potentially improve the symptoms of some of these conditions. This review summarizes recent findings on the functions of some of the genes responsible for ID syndromes and some of the new potential pharmacological treatments for these diseases.
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Affiliation(s)
- Chiara Verpelli
- CNR Institute of Neuroscience, Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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107
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Verpelli C, Montani C, Vicidomini C, Heise C, Sala C. Mutations of the synapse genes and intellectual disability syndromes. Eur J Pharmacol 2013; 719:112-116. [PMID: 23872408 DOI: 10.1016/j.ejphar.2013.07.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/04/2013] [Accepted: 07/01/2013] [Indexed: 01/10/2023]
Abstract
Intellectual disability syndromes have been found associated to numerous mutated genes that code for proteins functionally involved in synapse formation, the regulation of dendritic spine morphology, the regulation of the synaptic cytoskeleton or the synthesis and degradation of specific synapse proteins. These studies have strongly demonstrated that even mild alterations in synapse morphology and function give rise to mild or severe alteration in intellectual abilities. Interestingly, pharmacological agents that are able to counteract these morphological and functional synaptic anomalies can also improve the symptoms of some of these conditions. This review is summarizing recent discoveries on the functions of some of the genes responsible for intellectual disability syndromes connected with synapse dysfunctions.
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Affiliation(s)
- Chiara Verpelli
- CNR Institute of Neuroscience and Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milano, Italy
| | - Caterina Montani
- CNR Institute of Neuroscience and Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milano, Italy
| | - Cinzia Vicidomini
- CNR Institute of Neuroscience and Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milano, Italy
| | - Christopher Heise
- CNR Institute of Neuroscience and Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milano, Italy
| | - Carlo Sala
- CNR Institute of Neuroscience and Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milano, Italy; Neuromuscular Diseases and Neuroimmunology, Neurological Institute Foundation Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
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108
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Protein tyrosine phosphatases PTPδ, PTPσ, and LAR: presynaptic hubs for synapse organization. Trends Neurosci 2013; 36:522-34. [PMID: 23835198 DOI: 10.1016/j.tins.2013.06.002] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/03/2013] [Accepted: 06/11/2013] [Indexed: 02/04/2023]
Abstract
Synapse development requires differentiation of presynaptic neurotransmitter release sites and postsynaptic receptive apparatus coordinated by synapse organizing proteins. In addition to the well-characterized neurexins, recent studies identified presynaptic type IIa receptor-type protein tyrosine phosphatases (RPTPs) as mediators of presynaptic differentiation and triggers of postsynaptic differentiation, thus extending the roles of RPTPs from axon outgrowth and guidance. Similarly to neurexins, RPTPs exist in multiple isoforms generated by alternative splicing that interact in a splice-selective code with diverse postsynaptic partners. The parallel RPTP and neurexin hub design facilitates synapse self-assembly through cooperation, pairs presynaptic similarity with postsynaptic diversity, and balances excitation with inhibition. Upon mutation of individual genes in neuropsychiatric disorders, imbalance of this synaptic organizing network may contribute to impaired cognitive function.
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109
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Bassani S, Zapata J, Gerosa L, Moretto E, Murru L, Passafaro M. The neurobiology of X-linked intellectual disability. Neuroscientist 2013; 19:541-52. [PMID: 23820068 DOI: 10.1177/1073858413493972] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
X-linked intellectual disability (XLID) affects 1% to 3% of the population. XLID subsumes several heterogeneous conditions, all of which are marked by cognitive impairment and reduced adaptive skills. XLID arises from mutations on the X chromosome; to date, 102 XLID genes have been identified. The proteins encoded by XLID genes are involved in higher brain functions, such as cognition, learning and memory, and their molecular role is the subject of intense investigation. Here, we review recent findings concerning a representative group of XLID proteins: the fragile X mental retardation protein; methyl-CpG-binding protein 2 and cyclin-dependent kinase-like 5 proteins, which are involved in Rett syndrome; the intracellular signaling molecules of the Rho guanosine triphosphatases family; and the class of cell adhesion molecules. We discuss how XLID gene mutations affect the structure and function of synapses.
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Affiliation(s)
- Silvia Bassani
- CNR Institute of Neuroscience, Department BIOMETRA, University of Milan, Milan, Italy
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110
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Penzes P, Buonanno A, Passafaro M, Sala C, Sweet RA. Developmental vulnerability of synapses and circuits associated with neuropsychiatric disorders. J Neurochem 2013; 126:165-82. [PMID: 23574039 PMCID: PMC3700683 DOI: 10.1111/jnc.12261] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/08/2013] [Indexed: 12/20/2022]
Abstract
Psychiatric and neurodegenerative disorders, including intellectual disability, autism spectrum disorders (ASD), schizophrenia (SZ), and Alzheimer's disease, pose an immense burden to society. Symptoms of these disorders become manifest at different stages of life: early childhood, adolescence, and late adulthood, respectively. Progress has been made in recent years toward understanding the genetic substrates, cellular mechanisms, brain circuits, and endophenotypes of these disorders. Multiple lines of evidence implicate excitatory and inhibitory synaptic circuits in the cortex and hippocampus as key cellular substrates of pathogenesis in these disorders. Excitatory/inhibitory balance--modulated largely by dopamine--critically regulates cortical network function, neural network activity (i.e. gamma oscillations) and behaviors associated with psychiatric disorders. Understanding the molecular underpinnings of synaptic pathology and neuronal network activity may thus provide essential insight into the pathogenesis of these disorders and can reveal novel drug targets to treat them. Here, we discuss recent genetic, neuropathological, and molecular studies that implicate alterations in excitatory and inhibitory synaptic circuits in the pathogenesis of psychiatric disorders across the lifespan.
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Affiliation(s)
- Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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111
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Hayashi T, Yoshida T, Ra M, Taguchi R, Mishina M. IL1RAPL1 associated with mental retardation and autism regulates the formation and stabilization of glutamatergic synapses of cortical neurons through RhoA signaling pathway. PLoS One 2013; 8:e66254. [PMID: 23785489 PMCID: PMC3681934 DOI: 10.1371/journal.pone.0066254] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/02/2013] [Indexed: 11/20/2022] Open
Abstract
Interleukin-1 receptor accessory protein-like 1 (IL1RAPL1) is associated with X-linked mental retardation and autism spectrum disorder. We found that IL1RAPL1 regulates synapse formation of cortical neurons. To investigate how IL1RAPL1 controls synapse formation, we here screened IL1RAPL1-interacting proteins by affinity chromatography and mass spectroscopy. IL1RAPL1 interacted with Mcf2-like (Mcf2l), a Rho guanine nucleotide exchange factor, through the cytoplasmic Toll/IL-1 receptor domain. Knockdown of endogenous Mcf2l and treatment with an inhibitor of Rho-associated protein kinase (ROCK), the downstream kinase of RhoA, suppressed IL1RAPL1-induced excitatory synapse formation of cortical neurons. Furthermore, we found that the expression of IL1RAPL1 affected the turnover of AMPA receptor subunits. Insertion of GluA1-containing AMPA receptors to the cell surface was decreased, whereas that of AMPA receptors composed of GluA2/3 was enhanced. Mcf2l knockdown and ROCK inhibitor treatment diminished the IL1RAPL1-induced changes of AMPA receptor subunit insertions. Our results suggest that Mcf2l-RhoA-ROCK signaling pathway mediates IL1RAPL1-dependent formation and stabilization of glutamatergic synapses of cortical neurons.
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Affiliation(s)
- Takashi Hayashi
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Moonjin Ra
- Department of Metabolome, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Ryo Taguchi
- Department of Metabolome, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Masayoshi Mishina
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
- Brain Science Laboratory, The Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, Japan
- * E-mail:
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112
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Mironova YA, Giger RJ. Where no synapses go: gatekeepers of circuit remodeling and synaptic strength. Trends Neurosci 2013; 36:363-73. [PMID: 23642707 DOI: 10.1016/j.tins.2013.04.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 02/07/2023]
Abstract
Growth inhibitory molecules in the adult mammalian central nervous system (CNS) have been implicated in the blocking of axonal sprouting and regeneration following injury. Prominent CNS regeneration inhibitors include Nogo-A, oligodendrocyte myelin glycoprotein (OMgp), and chondroitin sulfate proteoglycans (CSPGs), and a key question concerns their physiological role in the naïve CNS. Emerging evidence suggests novel functions in dendrites and at synapses of glutamatergic neurons. CNS regeneration inhibitors target the neuronal actin cytoskeleton to regulate dendritic spine maturation, long-term synapse stability, and Hebbian forms of synaptic plasticity. This is accomplished in part by antagonizing plasticity-promoting signaling pathways activated by neurotrophic factors. Altered function of CNS regeneration inhibitors is associated with mental illness and loss of long-lasting memory, suggesting unexpected and novel physiological roles for these molecules in brain health.
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, 3065 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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113
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Barone C, Bianca S, Luciano D, Di Benedetto D, Vinci M, Fichera M. Intragenic ILRAPL1 deletion in a male patient with intellectual disability, mild dysmorphic signs, deafness, and behavioral problems. Am J Med Genet A 2013; 161A:1381-5. [PMID: 23613341 DOI: 10.1002/ajmg.a.35860] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 12/14/2012] [Indexed: 11/07/2022]
Abstract
Intellectual disability affects approximately 2% of the population, with affected males outnumbering affected female, partly due to disturbances involving X-linked genes. To date >90 genes associated with X-linked intellectual disability have been identified and, among these, IL1RAPL1 (interleukin 1 receptor accessory protein-like 1), was first described and mapped to Xp21.3-22.1 in 1999. Intragenic deletions of IL1RAPL1, only rarely identified, have mostly been associated with nonspecific intellectual disability (IDX) and autism spectrum disorder. Array-CGH analysis performed in our patient with intellectual disability, mild dysmorphic signs and changes in behavior identified a 285 Kb deletion in chromosome Xp21.3-21.2, with breakpoints lying in IL1RAPL1 gene intron 2 and intron 3. This is the first patient reported in literature with deletion of only exon 3 of IL1RAPL1 gene. Our patient also exhibits bilateral progressive neurosensorial deafness, which has not been previously associated with IL1RAPL1 mutations.
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Affiliation(s)
- Chiara Barone
- Centro di Consulenza Genetica e Teratologia della Riproduzione, Dipartimento Materno Infantile, ARNAS Garibaldi Nesima, Catania, Italy
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114
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Goines PE, Ashwood P. Cytokine dysregulation in autism spectrum disorders (ASD): possible role of the environment. Neurotoxicol Teratol 2013; 36:67-81. [PMID: 22918031 PMCID: PMC3554862 DOI: 10.1016/j.ntt.2012.07.006] [Citation(s) in RCA: 199] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 07/03/2012] [Accepted: 07/31/2012] [Indexed: 02/07/2023]
Abstract
Autism spectrum disorders (ASD) are neurodevelopmental diseases that affect an alarming number of individuals. The etiological basis of ASD is unclear, and evidence suggests it involves both genetic and environmental factors. There are many reports of cytokine imbalances in ASD. These imbalances could have a pathogenic role, or they may be markers of underlying genetic and environmental influences. Cytokines act primarily as mediators of immunological activity but they also have significant interactions with the nervous system. They participate in normal neural development and function, and inappropriate activity can have a variety of neurological implications. It is therefore possible that cytokine dysregulation contributes directly to neural dysfunction in ASD. Further, cytokine profiles change dramatically in the face of infection, disease, and toxic exposures. Imbalances in cytokines may represent an immune response to environmental contributors to ASD. The following review is presented in two main parts. First, we discuss select cytokines implicated in ASD, including IL-1Β, IL-6, IL-4, IFN-γ, and TGF-Β, and focus on their role in the nervous system. Second, we explore several neurotoxic environmental factors that may be involved in the disorders, and focus on their immunological impacts. This review represents an emerging model that recognizes the importance of both genetic and environmental factors in ASD etiology. We propose that the immune system provides critical clues regarding the nature of the gene by environment interactions that underlie ASD pathophysiology.
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Affiliation(s)
- Paula E. Goines
- University of California, Davis, School of Veterinary Medicine, Department of Molecular Biosciences
| | - Paul Ashwood
- University of California, Davis, School of Medicine, Department of Medical Microbiology and Immunology
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115
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Pettem KL, Yokomaku D, Takahashi H, Ge Y, Craig AM. Interaction between autism-linked MDGAs and neuroligins suppresses inhibitory synapse development. ACTA ACUST UNITED AC 2013; 200:321-36. [PMID: 23358245 PMCID: PMC3563690 DOI: 10.1083/jcb.201206028] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Rare variants in MDGAs (MAM domain-containing glycosylphosphatidylinositol anchors), including multiple protein-truncating deletions, are linked to autism and schizophrenia, but the function of these genes is poorly understood. Here, we show that MDGA1 and MDGA2 bound to neuroligin-2 inhibitory synapse-organizing protein, also implicated in neurodevelopmental disorders. MDGA1 inhibited the synapse-promoting activity of neuroligin-2, without altering neuroligin-2 surface trafficking, by inhibiting interaction of neuroligin-2 with neurexin. MDGA binding and suppression of synaptogenic activity was selective for neuroligin-2 and not neuroligin-1 excitatory synapse organizer. Overexpression of MDGA1 in cultured rat hippocampal neurons reduced inhibitory synapse density without altering excitatory synapse density. Furthermore, RNAi-mediated knockdown of MDGA1 selectively increased inhibitory but not excitatory synapse density. These results identify MDGA1 as one of few identified negative regulators of synapse development with a unique selectivity for inhibitory synapses. These results also place MDGAs in the neurexin-neuroligin synaptic pathway implicated in neurodevelopmental disorders and support the idea that an imbalance between inhibitory and excitatory synapses may contribute to these disorders.
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Affiliation(s)
- Katherine L Pettem
- Brain Research Centre and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
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116
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Hendriks WJAJ, Elson A, Harroch S, Pulido R, Stoker A, den Hertog J. Protein tyrosine phosphatases in health and disease. FEBS J 2012; 280:708-30. [DOI: 10.1111/febs.12000] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 08/17/2012] [Accepted: 08/28/2012] [Indexed: 01/06/2023]
Affiliation(s)
| | - Ari Elson
- Department of Molecular Genetics; The Weizmann Institute of Science; Rehovot; Israel
| | - Sheila Harroch
- Department of Neuroscience; Institut Pasteur; Paris; France
| | - Rafael Pulido
- Centro de Investigación Príncipe Felipe; Valencia; Spain
| | - Andrew Stoker
- Neural Development Unit; Institute of Child Health; University College London; UK
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117
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Jordan KW, Craver KL, Magwire MM, Cubilla CE, Mackay TFC, Anholt RRH. Genome-wide association for sensitivity to chronic oxidative stress in Drosophila melanogaster. PLoS One 2012; 7:e38722. [PMID: 22715409 PMCID: PMC3371005 DOI: 10.1371/journal.pone.0038722] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 05/14/2012] [Indexed: 12/20/2022] Open
Abstract
Reactive oxygen species (ROS) are a common byproduct of mitochondrial energy metabolism, and can also be induced by exogenous sources, including UV light, radiation, and environmental toxins. ROS generation is essential for maintaining homeostasis by triggering cellular signaling pathways and host defense mechanisms. However, an imbalance of ROS induces oxidative stress and cellular death and is associated with human disease, including age-related locomotor impairment. To identify genes affecting sensitivity and resistance to ROS-induced locomotor decline, we assessed locomotion of aged flies of the sequenced, wild-derived lines from the Drosophila melanogaster Genetics Reference Panel on standard medium and following chronic exposure to medium supplemented with 3 mM menadione sodium bisulfite (MSB). We found substantial genetic variation in sensitivity to oxidative stress with respect to locomotor phenotypes. We performed genome-wide association analyses to identify candidate genes associated with variation in sensitivity to ROS-induced decline in locomotor performance, and confirmed the effects for 13 of 16 mutations tested in these candidate genes. Candidate genes associated with variation in sensitivity to MSB-induced oxidative stress form networks of genes involved in neural development, immunity, and signal transduction. Many of these genes have human orthologs, highlighting the utility of genome-wide association in Drosophila for studying complex human disease.
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Affiliation(s)
- Katherine W. Jordan
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Kyle L. Craver
- Department of Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Michael M. Magwire
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Carmen E. Cubilla
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Trudy F. C. Mackay
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Robert R. H. Anholt
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, United States of America
- Department of Biology, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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118
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Verpelli C, Sala C. Molecular and synaptic defects in intellectual disability syndromes. Curr Opin Neurobiol 2012; 22:530-6. [DOI: 10.1016/j.conb.2011.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 09/16/2011] [Accepted: 09/22/2011] [Indexed: 12/11/2022]
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119
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Differences in AMPA and kainate receptor interactomes facilitate identification of AMPA receptor auxiliary subunit GSG1L. Cell Rep 2012; 1:590-8. [PMID: 22813734 DOI: 10.1016/j.celrep.2012.05.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/02/2012] [Accepted: 05/07/2012] [Indexed: 12/20/2022] Open
Abstract
AMPA receptor (AMPA-R) complexes consist of channel-forming subunits, GluA1-4, and auxiliary proteins, including TARPs, CNIHs, synDIG1, and CKAMP44, which can modulate AMPA-R function in specific ways. The combinatorial effects of four GluA subunits binding to various auxiliary subunits amplify the functional diversity of AMPA-Rs. The significance and magnitude of molecular diversity, however, remain elusive. To gain insight into the molecular complexity of AMPA and kainate receptors, we compared the proteins that copurify with each receptor type in the rat brain. This interactome study identified the majority of known interacting proteins and, more importantly, provides candidates for additional studies. We validate the claudin homolog GSG1L as a newly identified binding protein and unique modulator of AMPA-R gating, as determined by detailed molecular, cellular, electrophysiological, and biochemical experiments. GSG1L extends the functional variety of AMPA-R complexes, and further investigation of other candidates may reveal additional complexity of ionotropic glutamate receptor function.
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Interleukin-1 receptor accessory protein organizes neuronal synaptogenesis as a cell adhesion molecule. J Neurosci 2012; 32:2588-600. [PMID: 22357843 DOI: 10.1523/jneurosci.4637-11.2012] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Interleukin-1 receptor accessory protein (IL-1RAcP) is the essential component of receptor complexes mediating immune responses to interleukin-1 family cytokines. IL-1RAcP in the brain exists in two isoforms, IL-1RAcP and IL-1RAcPb, differing only in the C-terminal region. Here, we found robust synaptogenic activities of IL-1RAcP in cultured cortical neurons. Knockdown of IL-1RAcP isoforms in cultured cortical neurons suppressed synapse formation as indicated by decreases of active zone protein Bassoon puncta and dendritic protrusions. IL-1RAcP recovered the accumulation of presynaptic Bassoon puncta, while IL-1RAcPb rescued both Bassoon puncta and dendritic protrusions. Consistently, the expression of IL-1RAcP in cortical neurons enhances the accumulation of Bassoon puncta and that of IL-1RAcPb stimulated both Bassoon puncta accumulation and spinogenesis. IL-1RAcP interacted with protein tyrosine phosphatase (PTP) δ through the extracellular domain. Mini-exon peptides in the Ig-like domains of PTPδ splice variants were critical for their efficient binding to IL-1RAcP. The synaptogenic activities of IL-1RAcP isoforms were diminished in cortical neurons from PTPδ knock-out mice. Correspondingly, PTPδ required IL-1RAcPb to induce postsynaptic differentiation. Thus, IL-1RAcPb bidirectionally regulated synapse formation of cortical neurons. Furthermore, the spine densities of cortical and hippocampal pyramidal neurons were reduced in IL-1RAcP knock-out mice lacking both isoforms. These results suggest that IL-1RAcP isoforms function as trans-synaptic cell adhesion molecules in the brain and organize synapse formation. Thus, IL-1RAcP represents an interesting molecular link between immune systems and synapse formation in the brain.
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Selective control of inhibitory synapse development by Slitrk3-PTPδ trans-synaptic interaction. Nat Neurosci 2012; 15:389-98, S1-2. [PMID: 22286174 PMCID: PMC3288805 DOI: 10.1038/nn.3040] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 01/03/2012] [Indexed: 02/06/2023]
Abstract
Balanced development of excitatory and inhibitory synapses is required for normal brain function, and their imbalance may underlie pathogenesis of neuropsychiatric disorders. Compared with many identified trans-synaptic adhesion complexes that organize excitatory synapses, little is known about organizers specific for inhibitory synapses. Here we report Slit and NTRK-like family member 3 (Slitrk3) as a postsynaptic adhesion molecule that selectively regulates inhibitory synapse development via trans-interaction with axonal tyrosine phosphatase receptor PTPδ. Slitrk3 expressed in fibroblasts triggers only inhibitory presynaptic differentiation in contacting axons of cocultured rat hippocampal neurons. Recombinant Slitrk3 preferentially localizes to inhibitory postsynaptic sites. Slitrk3-deficient mice exhibit decreases in inhibitory but not excitatory synapse number and function in hippocampal CA1 neurons and exhibit increased seizure susceptibility and spontaneous epileptiform activity. Slitrk3 requires trans-interaction with axonal PTPδ to induce inhibitory presynaptic differentiation. These results identify Slitrk3-PTPδ as an inhibitory-specific trans-synaptic organizing complex required for normal functional GABAergic synapse development.
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Chen X, Yoshida T, Sagara H, Mikami Y, Mishina M. Protein tyrosine phosphatase σ regulates the synapse number of zebrafish olfactory sensory neurons. J Neurochem 2011; 119:532-43. [PMID: 21812780 DOI: 10.1111/j.1471-4159.2011.07411.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The formation and refinement of synaptic connections are key steps of neural development to establish elaborate brain networks. To investigate the functional role of protein tyrosine phosphatase (PTP) σ, we employed an olfactory sensory neuron (OSN)-specific gene manipulation system in combination with in vivo imaging of transparent zebrafish embryos. Knockdown of PTPσ enhanced the accumulation of synaptic vesicles in the axon terminals of OSNs. The exaggerated accumulation of synaptic vesicles was restored to the normal level by the OSN-specific expression of PTPσ, indicating that presynaptic PTPσ is responsible for the regulation of synaptic vesicle accumulation. Consistently, transient expression of a dominant-negative form of PTPσ in OSNs enhanced the accumulation of synaptic vesicles. The exaggerated accumulation of synaptic vesicles was reproduced in transgenic zebrafish lines carrying an OSN-specific expression vector of the dominant-negative PTPσ. By electron microscopic analysis of the transgenic line, we found the significant increase of the number of OSN-mitral cell synapses in the central zone of the olfactory bulb. The density of docked vesicles at the active zone was also increased significantly. Our results suggest that presynaptic PTPσ controls the number of OSN-mitral cell synapses by suppressing their excessive increase.
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Affiliation(s)
- Xigui Chen
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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