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Wang H, Yuan Y, Zhang Z, Yan H, Feng Y, Li W. Dysbindin-1C is required for the survival of hilar mossy cells and the maturation of adult newborn neurons in dentate gyrus. J Biol Chem 2014; 289:29060-72. [PMID: 25157109 DOI: 10.1074/jbc.m114.590927] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
DTNBP1 (dystrobrevin-binding protein 1), which encodes dysbindin-1, is one of the leading susceptibility genes for schizophrenia. Both dysbindin-1B and -1C isoforms are decreased, but the dysbindin-1A isoform is unchanged in schizophrenic hippocampal formation, suggesting dysbindin-1 isoforms may have distinct roles in schizophrenia. We found that mouse dysbindin-1C, but not dysbindin-1A, is localized in the hilar glutamatergic mossy cells of the dentate gyrus. The maturation rate of newborn neurons in sandy (sdy) mice, in which both dysbindin-1A and -1C are deleted, is significantly delayed when compared with that in wild-type mice or with that in muted (mu) mice in which dysbindin-1A is destabilized but dysbindin-1C is unaltered. Dysbindin-1C deficiency leads to a decrease in mossy cells, which causes the delayed maturation of newborn neurons. This suggests that dysbindin-1C, rather than dysbindin-1A, regulates adult hippocampal neurogenesis in a non-cell autonomous manner.
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Affiliation(s)
- Hao Wang
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the University of Chinese Academy of Sciences, Beijing 100039
| | - Yefeng Yuan
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the University of Chinese Academy of Sciences, Beijing 100039
| | - Zhao Zhang
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the University of Chinese Academy of Sciences, Beijing 100039
| | - Hui Yan
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the Department of Histology and Embryology, Shanxi Medical University, Taiyuan 030001, and
| | - Yaqin Feng
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the Department of Histology and Embryology, Shanxi Medical University, Taiyuan 030001, and
| | - Wei Li
- From the State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, the Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing 100053, China
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Extracellular Ca²⁺ per se inhibits quantal size of catecholamine release in adrenal slice chromaffin cells. Cell Calcium 2014; 56:202-7. [PMID: 25103334 DOI: 10.1016/j.ceca.2014.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/13/2014] [Accepted: 07/12/2014] [Indexed: 11/24/2022]
Abstract
Classic calcium hypothesis states that depolarization-induced increase in intracellular Ca(2+) concentration ([Ca(2+)]i) triggers vesicle exocytosis by increasing vesicle release probability in neurons and neuroendocrine cells. The extracellular Ca(2+), in this calcium hypothesis, serves as a reservoir of Ca(2+) source. Recently we find that extracellular Ca(2+)per se inhibits the [Ca(2+)]i dependent vesicle exocytosis, but it remains unclear whether quantal size is regulated by extracellular, or intracellular Ca(2+) or both. In this work we showed that, in physiological condition, extracellular Ca(2+) per se specifically inhibited the quantal size of single vesicle release in rat adrenal slice chromaffin cells. The extracellular Ca(2+) in physiological concentration (2.5 mM) directly regulated fusion pore kinetics of spontaneous quantal release of catecholamine. In addition, removal of extracellular Ca(2+) directly triggered vesicle exocytosis without eliciting intracellular Ca(2+). We propose that intracellular Ca(2+) and extracellular Ca(2+)per se cooperately regulate single vesicle exocytosis. The vesicle release probability was jointly modulated by both intracellular and extracellular Ca(2+), while the vesicle quantal size was mainly determined by extracellular Ca(2+) in chromaffin cells physiologically.
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Pinner AL, Haroutunian V, Meador-Woodruff JH. Alterations of the myristoylated, alanine-rich C kinase substrate (MARCKS) in prefrontal cortex in schizophrenia. Schizophr Res 2014; 154:36-41. [PMID: 24568864 PMCID: PMC3999918 DOI: 10.1016/j.schres.2014.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 01/27/2014] [Accepted: 02/01/2014] [Indexed: 11/29/2022]
Abstract
Abnormal synaptic plasticity has been implicated in the cognitive deficits seen in schizophrenia, where alterations have been found in neurotransmission, signaling and dendritic dynamics. Rapid rearrangement of the actin cytoskeleton is critical for plasticity and abnormalities of molecular regulators of this process are candidates for understanding mechanisms underlying these changes in schizophrenia. The myristoylated, alanine-rich C-kinase substrate (MARCKS) is crucial for many roles associated with synaptic plasticity, including facilitation of neurotransmission, dendritic branching and in turn cognitive function. Accordingly, we hypothesized that this protein is abnormally expressed or regulated in schizophrenia. We measured protein expression of MARCKS by Western blot analysis in postmortem samples of dorsolateral prefrontal cortex (DLPFC) from elderly schizophrenia patients (N=16) and a comparison group (N=20). We also assayed phosphorylated-MARCKS (pMARCKS), given the role of phosphorylation in reversing membrane association by MARCKS. We found decreased expression of both MARCKS and pMARCKS in schizophrenia. Altered myristoylation may be a mechanism that explains this down-regulation of MARCKS, so we also assayed expression of the two isoforms of the key myristoylation enzyme, NMT, and an enzymatic inhibitor of this enzyme, NMT-inhibitor protein (NIP71) by Western blotting in these same subjects. Expression did not change between groups for these proteins, suggesting a mechanism other than myristoylation is responsible for decreased MARCKS expression in schizophrenia. These data suggest a potential mechanism underlying aspects of altered synaptic plasticity observed in schizophrenia.
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Affiliation(s)
- Anita L. Pinner
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
,Corresponding author: CIRC 593, 1719 6 Ave South, Birmingham, AL 35294-0021, USA, Tel: +1 205 996 6212, Fax: + 1 205 975 4879,
| | - Vahram Haroutunian
- Department of Psychiatry, Mt. Sinai School of Medicine, New York, NY, USA
| | - James H. Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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Abstract
Psychosis is an abnormal mental state characterized by disorganization, delusions and hallucinations. Animal models have become an increasingly important research tool in the effort to understand both the underlying pathophysiology and treatment of psychosis. There are multiple animal models for psychosis, with each formed by the coupling of a manipulation and a measurement. In this manuscript we do not address the diseases of which psychosis is a prominent comorbidity. Instead, we summarize the current state of affairs and future directions for animal models of psychosis. To accomplish this, our manuscript will first discuss relevant behavioral and electrophysiological measurements. We then provide an overview of the different manipulations that are combined with these measurements to produce animal models. The strengths and limitations of each model will be addressed in order to evaluate its cross-species comparability.
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55
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Importing, caring, breeding, genotyping, and phenotyping a genetic mouse in a Chinese university. J Mol Neurosci 2014; 53:487-92. [PMID: 24385195 DOI: 10.1007/s12031-013-0195-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
Abstract
The genetic manipulation of the laboratory mouse has been well developed and generated more and more mouse lines for biomedical research. To advance our science exploration, it is necessary to share genetically modified mouse lines with collaborators between institutions, even in different countries. The transfer process is complicated. Significant paperwork and coordination are required, concerning animal welfare, intellectual property rights, colony health status, and biohazard. Here, we provide a practical example of importing a transgenic mice line, Dynamin 1 knockout mice, from Yale University in the USA to Perking University in China for studying cell secretion. This example including the length of time that required for paper work, mice quarantine at the receiving institution, and expansion of the mouse line for experiments. The procedure described in this paper for delivery live transgenic mice from USA to China may serve a simple reference for transferring mouse lines between other countries too.
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56
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Moran PM, O'Tuathaigh CM, Papaleo F, Waddington JL. Dopaminergic function in relation to genes associated with risk for schizophrenia. PROGRESS IN BRAIN RESEARCH 2014; 211:79-112. [DOI: 10.1016/b978-0-444-63425-2.00004-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Orozco IJ, Koppensteiner P, Ninan I, Arancio O. The schizophrenia susceptibility gene DTNBP1 modulates AMPAR synaptic transmission and plasticity in the hippocampus of juvenile DBA/2J mice. Mol Cell Neurosci 2013; 58:76-84. [PMID: 24321452 DOI: 10.1016/j.mcn.2013.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 10/31/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022] Open
Abstract
The dystrobrevin binding protein (DTNBP) 1 gene has emerged over the last decade as a potential susceptibility locus for schizophrenia. While no causative mutations have been found, reduced expression of the encoded protein, dysbindin, was reported in patients. Dysbindin likely plays a role in the neuronal trafficking of proteins including receptors. One important pathway suspected to be affected in schizophrenia is the fast excitatory glutamatergic transmission mediated by AMPA receptors. Here, we investigated excitatory synaptic transmission and plasticity in hippocampal neurons from dysbindin-deficient sandy mice bred on the DBA/2J strain. In cultured neurons an enhancement of AMPAR responses was observed. The enhancement of AMPAR-mediated transmission was confirmed in hippocampal CA3-CA1 synapses, and was not associated with changes in the expression of GluA1-4 subunits or an increase in GluR2-lacking receptor complexes. Lastly, an enhancement in LTP was also found in these mice. These data provide compelling evidence that dysbindin, a widely suspected susceptibility protein in schizophrenia, is important for AMPAR-mediated synaptic transmission and plasticity in the developing hippocampus.
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Affiliation(s)
- Ian J Orozco
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
| | - Peter Koppensteiner
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Ipe Ninan
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
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58
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Wondolowski J, Dickman D. Emerging links between homeostatic synaptic plasticity and neurological disease. Front Cell Neurosci 2013; 7:223. [PMID: 24312013 PMCID: PMC3836049 DOI: 10.3389/fncel.2013.00223] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 11/03/2013] [Indexed: 01/22/2023] Open
Abstract
Homeostatic signaling systems are ubiquitous forms of biological regulation, having been studied for hundreds of years in the context of diverse physiological processes including body temperature and osmotic balance. However, only recently has this concept been brought to the study of excitatory and inhibitory electrical activity that the nervous system uses to establish and maintain stable communication. Synapses are a primary target of neuronal regulation with a variety of studies over the past 15 years demonstrating that these cellular junctions are under bidirectional homeostatic control. Recent work from an array of diverse systems and approaches has revealed exciting new links between homeostatic synaptic plasticity and a variety of seemingly disparate neurological and psychiatric diseases. These include autism spectrum disorders, intellectual disabilities, schizophrenia, and Fragile X Syndrome. Although the molecular mechanisms through which defective homeostatic signaling may lead to disease pathogenesis remain unclear, rapid progress is likely to be made in the coming years using a powerful combination of genetic, imaging, electrophysiological, and next generation sequencing approaches. Importantly, understanding homeostatic synaptic plasticity at a cellular and molecular level may lead to developments in new therapeutic innovations to treat these diseases. In this review we will examine recent studies that demonstrate homeostatic control of postsynaptic protein translation, retrograde signaling, and presynaptic function that may contribute to the etiology of complex neurological and psychiatric diseases.
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Affiliation(s)
- Joyce Wondolowski
- Department of Biology, University of Southern California Los Angeles, CA, USA
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59
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Glen WB, Horowitz B, Carlson GC, Cannon TD, Talbot K, Jentsch JD, Lavin A. Dysbindin-1 loss compromises NMDAR-dependent synaptic plasticity and contextual fear conditioning. Hippocampus 2013; 24:204-13. [PMID: 24446171 DOI: 10.1002/hipo.22215] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 09/23/2013] [Accepted: 09/25/2013] [Indexed: 01/19/2023]
Abstract
Genetic variants in DTNBP1 encoding the protein dysbindin-1 have often been associated with schizophrenia and with the cognitive deficits prominent in that disorder. Because impaired function of the hippocampus is thought to play a role in these memory deficits and because NMDAR-dependent synaptic plasticity in this region is a proposed biological substrate for some hippocampal-dependent memory functions in schizophrenia, we hypothesized that reduced dysbindin-1 expression would lead to impairments in NMDAR-dependent synaptic plasticity and in contextual fear conditioning. Acute slices from male mice carrying 0, 1, or 2 null mutant alleles of the Dtnbp1 gene were prepared, and field recordings from the CA1 striatum radiatum were obtained before and after tetanization of Schaffer collaterals of CA3 pyramidal cells. Mice homozygous for the null mutation in Dtnbp1 exhibited significantly reduced NMDAR-dependent synaptic potentiation compared to wild type mice, an effect that could be rescued by bath application of the NMDA receptor coagonist glycine (10 μM). Behavioral testing in adult mice revealed deficits in hippocampal memory processes. Homozygous null mice exhibited lower conditional freezing, without a change in the response to shock itself, indicative of a learning and memory deficit. Taken together, these results indicate that a loss of dysbindin-1 impairs hippocampal plasticity which may, in part, explain the role dysbindin-1 plays in the cognitive impairments of schizophrenia.
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Affiliation(s)
- W Bailey Glen
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
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60
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Jia J, Zhao J, Hu Z, Lindberg D, Li Z. Age-dependent regulation of synaptic connections by dopamine D2 receptors. Nat Neurosci 2013; 16:1627-36. [PMID: 24121738 PMCID: PMC3832846 DOI: 10.1038/nn.3542] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/12/2013] [Indexed: 12/14/2022]
Abstract
Dopamine D2 receptors (D2R) are G protein-coupled receptors that modulate synaptic transmission and are important for various brain functions, including learning and working memory. Abnormal D2R signaling has been implicated in psychiatric disorders such as schizophrenia. Here we report a new function of D2R in dendritic spine morphogenesis. Activation of D2R reduced spine number via GluN2B- and cAMP-dependent mechanisms in mice. Notably, this regulation occurred only during adolescence. During this period, D2R overactivation caused by mutations in the schizophrenia risk gene Dtnbp1 led to spine deficiency, dysconnectivity in the entorhinal-hippocampal circuit and impairment of spatial working memory. Notably, these defects could be ameliorated by D2R blockers administered during adolescence. Our findings suggest an age-dependent function of D2R in spine development, provide evidence that D2R dysfunction during adolescence impairs neuronal circuits and working memory, and indicate that adolescent interventions to prevent aberrant D2R activity protect against cognitive impairment.
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Affiliation(s)
- Jie–Min Jia
- Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jun Zhao
- Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhonghua Hu
- Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel Lindberg
- Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zheng Li
- Unit on Synapse Development and Plasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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61
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Matteucci A, Gaddini L, Macchia G, Varano M, Petrucci TC, Macioce P, Malchiodi-Albedi F, Ceccarini M. Developmental expression of dysbindin in Muller cells of rat retina. Exp Eye Res 2013; 116:1-8. [PMID: 23954924 DOI: 10.1016/j.exer.2013.08.006] [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: 03/13/2013] [Revised: 07/30/2013] [Accepted: 08/06/2013] [Indexed: 01/09/2023]
Abstract
Dysbindin, the product of the DTNBP1 gene, was identified by yeast two hybrid assay as a binding partner of dystrobrevin, a cytosolic component of the dystrophin protein complex. Although its functional role has not yet been completely elucidated, the finding that dysbindin assembles into the biogenesis of lysosome related organelles complex 1 (BLOC-1) suggests that it participates in intracellular trafficking and biogenesis of organelles and vesicles. Dysbindin is ubiquitous and in brain is expressed primarily in neurons. Variations at the dysbindin gene have been associated with increased risk for schizophrenia. As anomalies in retinal function have been reported in patients suffering from neuropsychiatric disorders, we investigated the expression of dysbindin in the retina. Our results show that differentially regulated dysbindin isoforms are expressed in rat retina during postnatal maturation. Interestingly, we found that dysbindin is mainly localized in Müller cells. The identification of dysbindin in glial cells may open new perspectives for a better understanding of the functional involvement of this protein in visual alterations associated to neuropsychiatric disorders.
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Affiliation(s)
- Andrea Matteucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy.
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62
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Tsoupri E, Capetanaki Y. Μyospryn: a multifunctional desmin-associated protein. Histochem Cell Biol 2013; 140:55-63. [PMID: 23748244 DOI: 10.1007/s00418-013-1103-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2013] [Indexed: 12/14/2022]
Abstract
Desmin, the muscle-specific intermediate filament protein, forms a 3D scaffold that links the contractile apparatus to the costameres of plasma membrane, intercalated disks, the nucleus, and also other membranous organelles. The cellular scaffold formed by desmin and its binding partners might be implicated in signaling and trafficking processes, vital mechanisms for the survival of the mammalian cell. One novel desmin-associated protein is the tripartite motif-like protein myospryn. Myospryn was initially identified as an associated partner to the biogenesis of lysosome-related organelles complex 1 protein dysbindin, implicating its potential involvement in vesicle trafficking and organelle biogenesis and/or positioning. Myospryn is also an A kinase anchoring protein, raising the possibility that together with desmin and other cytoskeletal and signaling proteins, it could participate in the subcellular targeting of protein kinase A activity in striated muscle. As with desmin, different members of this scaffold might play a crucial role in the pathogenesis of muscle disease, since any disturbance in these highly coordinated signaling pathways is expected to compromise efficient maintenance of structure-function integrity of muscle and lead to different cardiac and skeletal myopathies.
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Affiliation(s)
- Elsa Tsoupri
- Cell Biology Division, Center of Basic Research, Biomedical Research Foundation Academy of Athens, 11527, Athens, Greece
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63
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Larimore J, Ryder PV, Kim KY, Ambrose LA, Chapleau C, Calfa G, Gross C, Bassell GJ, Pozzo-Miller L, Smith Y, Talbot K, Park IH, Faundez V. MeCP2 regulates the synaptic expression of a Dysbindin-BLOC-1 network component in mouse brain and human induced pluripotent stem cell-derived neurons. PLoS One 2013; 8:e65069. [PMID: 23750231 PMCID: PMC3672180 DOI: 10.1371/journal.pone.0065069] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/22/2013] [Indexed: 02/06/2023] Open
Abstract
Clinical, epidemiological, and genetic evidence suggest overlapping pathogenic mechanisms between autism spectrum disorder (ASD) and schizophrenia. We tested this hypothesis by asking if mutations in the ASD gene MECP2 which cause Rett syndrome affect the expression of genes encoding the schizophrenia risk factor dysbindin, a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), and associated interacting proteins. We measured mRNA and protein levels of key components of a dysbindin interaction network by, quantitative real time PCR and quantitative immunohistochemistry in hippocampal samples of wild-type and Mecp2 mutant mice. In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients. We defined the distribution of the BLOC-1 subunit pallidin in human and mouse hippocampus and contrasted this distribution with that of symptomatic Mecp2 mutant mice. Neurons from mutant mice and Rett syndrome patients displayed selectively reduced levels of pallidin transcript. Pallidin immunoreactivity decreased in the hippocampus of symptomatic Mecp2 mutant mice, a feature most prominent at asymmetric synapses as determined by immunoelectron microcopy. Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice. Similarly, BDNF content was reduced in the hippocampus of BLOC-1 deficient mice suggesting that genetic defects in BLOC-1 are upstream of the BDNF phenotype in Mecp2 deficient mice. Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD.
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Affiliation(s)
- Jennifer Larimore
- Department of Biology, Agnes Scott College, Decatur, Georgia, United States of America
| | - Pearl V. Ryder
- Cell Biology, Emory University, Atlanta, Georgia, United States of America
| | - Kun-Yong Kim
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - L. Alex Ambrose
- Department of Biology, Agnes Scott College, Decatur, Georgia, United States of America
| | - Christopher Chapleau
- Department of Neurobiology, The University of Alabama, Birmingham, Alabama, United States of America
| | - Gaston Calfa
- Department of Neurobiology, The University of Alabama, Birmingham, Alabama, United States of America
| | - Christina Gross
- Cell Biology, Emory University, Atlanta, Georgia, United States of America
| | - Gary J. Bassell
- Cell Biology, Emory University, Atlanta, Georgia, United States of America
| | - Lucas Pozzo-Miller
- Department of Neurobiology, The University of Alabama, Birmingham, Alabama, United States of America
| | - Yoland Smith
- Department of Neurology, Emory University, Atlanta, Georgia, United States of America
- Yerkes National Primate Center, Emory University, Atlanta, Georgia, United States of America
| | - Konrad Talbot
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Victor Faundez
- Cell Biology, Emory University, Atlanta, Georgia, United States of America
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64
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Saggu S, Cannon TD, Jentsch JD, Lavin A. Potential molecular mechanisms for decreased synaptic glutamate release in dysbindin-1 mutant mice. Schizophr Res 2013; 146:254-63. [PMID: 23473812 PMCID: PMC3628687 DOI: 10.1016/j.schres.2013.01.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 01/14/2023]
Abstract
Behavioral genetic studies of humans have associated variation in the DTNBP1 gene with schizophrenia and its cognitive deficit phenotypes. The protein encoded by DTNBP1, dysbindin-1, is expressed in forebrain neurons where it interacts with proteins mediating vesicular trafficking and exocytosis. It has been shown that loss of dysbindin-1 results in a decrease in glutamate release in the prefrontal cortex; however the mechanisms underlying this decrease are not fully understood. In order to investigate this question, we evaluated dysbindin-1 null mutant mice, using electrophysiological recordings of prefrontal cortical neurons, imaging studies of vesicles, calcium dynamics and Western blot measures of synaptic proteins and Ca(2+) channels. Dysbindin-1 null mice showed a decrease in the ready releasable pool of synaptic vesicles, decreases in quantal size, decreases in the probability of release and deficits in the rate of endo- and exocytosis compared with wild-type controls. Moreover, the dysbindin-1 null mice show decreases in the [Ca(2+)]i,expression of L- and N-type Ca(2+)channels and several proteins involved in synaptic vesicle trafficking and priming. Our results provide new insights into the mechanisms of action of dysbindin-1.
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Affiliation(s)
- Shalini Saggu
- Dept of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Tyrone D. Cannon
- Depts of Psychology and Psychiatry & Biobehavioral Sciences, University of California, Los Angeles, CA
| | - J. David Jentsch
- Dept of Human Genetics, University of California, Los Angeles, CA
| | - Antonieta Lavin
- Dept of Neuroscience, Medical University of South Carolina, Charleston, SC
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65
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Liu X, Hong SI, Park SJ, dela Peña JB, Che H, Yoon SY, Kim DH, Kim JM, Cai M, Risbrough V, Geyer MA, Shin CY, Cheong JH, Park H, Lew JH, Ryu JH. The ameliorating effects of 5,7-dihydroxy-6-methoxy-2(4-phenoxyphenyl)-4H-chromene-4-one, an oroxylin A derivative, against memory impairment and sensorimotor gating deficit in mice. Arch Pharm Res 2013; 36:854-63. [DOI: 10.1007/s12272-013-0106-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/21/2013] [Indexed: 12/31/2022]
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66
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Carr GV, Jenkins KA, Weinberger DR, Papaleo F. Loss of dysbindin-1 in mice impairs reward-based operant learning by increasing impulsive and compulsive behavior. Behav Brain Res 2013; 241:173-84. [PMID: 23261874 PMCID: PMC3556458 DOI: 10.1016/j.bbr.2012.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/08/2012] [Accepted: 12/12/2012] [Indexed: 12/30/2022]
Abstract
The dystrobrevin-binding protein 1 (DTNBP1) gene, which encodes the dysbindin-1 protein, is a potential schizophrenia susceptibility gene. Polymorphisms in the DTNBP1 gene have been associated with altered cognitive abilities. In the present study, dysbindin-1 null mutant (dys-/-), heterozygous (dys+/-), and wild-type (dys+/+) mice, on a C57BL/6J genetic background, were tested in either a match to sample or nonmatch to sample visual discrimination task. This visual discrimination task was designed to measure rule learning and detect any changes in response timing over the course of testing. Dys-/- mice displayed significant learning deficits and required more trials to acquire this task. However, once criterion was reached, there were no differences between the genotypes on any behavioral measures. Dys-/- mice exhibited increased compulsive and impulsive behaviors compared to control littermates suggesting the inability to suppress incorrectly-timed responses underlies their increased time to acquisition. Indeed, group comparisons of behavior differences between the first and last day of testing showed that only dys-/- mice consistently decreased measures of perseverative, premature, timeout, and total responses. These findings illustrate how some aspects of altered cognitive performance in dys-/- mice might be related to increased impulsive and compulsive behaviors, analogous to cognitive deficits in some individuals with psychiatric disorders.
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Affiliation(s)
- Gregory V. Carr
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Kimberly A. Jenkins
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Daniel R. Weinberger
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
- Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, MD, USA
- Department of Psychiatry, Neurology, and Neuroscience and the Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Francesco Papaleo
- Clinical Brain Disorders Branch; Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
- Dipartimento di Scienze del Farmaco, Universita’ degli Studi di Padova, Largo Meneghetti, 2, 35131 Padova, Italy
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67
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Wei AH, Li W. Hermansky-Pudlak syndrome: pigmentary and non-pigmentary defects and their pathogenesis. Pigment Cell Melanoma Res 2012; 26:176-92. [DOI: 10.1111/pcmr.12051] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Affiliation(s)
| | - Wei Li
- State Key Laboratory of Molecular Developmental Biology; Institute of Genetics & Developmental Biology; Chinese Academy of Sciences; Beijing; China
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68
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Abstract
GABAergic interneurons of the cerebral cortex (cINs) play crucial roles in many aspects of cortical function. The diverse types of cINs are classified into subgroups according to their morphology, intrinsic physiology, neurochemical markers and synaptic targeting. Recent advances in mouse genetics, imaging and electrophysiology techniques have greatly advanced our efforts to understand the role of normal cIN function and its dysfunction in neuropsychiatric disorders. In schizophrenia (SCZ), a wealth of data suggests that cIN function is perturbed, and that interneuron dysfunction may underlie key symptoms of the disease. In this review, we discuss the link between cINs and SCZ, focusing on the evidence for GABAergic signaling deficits from both SCZ patients and mouse models.
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69
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Ayalew M, Le-Niculescu H, Levey DF, Jain N, Changala B, Patel SD, Winiger E, Breier A, Shekhar A, Amdur R, Koller D, Nurnberger JI, Corvin A, Geyer M, Tsuang MT, Salomon D, Schork NJ, Fanous AH, O'Donovan MC, Niculescu AB. Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction. Mol Psychiatry 2012; 17:887-905. [PMID: 22584867 PMCID: PMC3427857 DOI: 10.1038/mp.2012.37] [Citation(s) in RCA: 322] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/28/2012] [Accepted: 03/05/2012] [Indexed: 02/07/2023]
Abstract
We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.
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Affiliation(s)
- M Ayalew
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - H Le-Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - D F Levey
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N Jain
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - B Changala
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S D Patel
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E Winiger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Breier
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R Amdur
- Washington DC VA Medical Center, Washington, DC, USA
| | - D Koller
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J I Nurnberger
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Corvin
- Department of Psychiatry, Trinity College, Dublin, Ireland
| | - M Geyer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - M T Tsuang
- Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - D Salomon
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - N J Schork
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A H Fanous
- Washington DC VA Medical Center, Washington, DC, USA
| | - M C O'Donovan
- Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff, UK
| | - A B Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Indianapolis VA Medical Center, Indianapolis, IN, USA
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Abstract
xCT is the functional subunit of the cystine/glutamate antiporter system xc−, which exchanges intracellular glutamate with extracellular cystine. xCT has been reported to play roles in the maintenance of intracellular redox and ambient extracellular glutamate, which may affect neuronal function. To assess a potential role of xCT in the mouse hippocampus, we performed fear conditioning and passive avoidance for long-term memories and examined hippocampal synaptic plasticity in wild-type mice and xCT-null mutants, sut mice. Long-term memory was impaired in sut mice. Normal basal synaptic transmission and short-term presynaptic plasticity at hippocampal Schaffer collateral–CA1 synapses were observed in sut mice. However, LTP (long-term potentiation) was significantly reduced in sut mice compared with their wild-type counterparts. Supplementation of extracellular glutamate did not reverse the reduction in LTP. Taken together, our results suggest that xCT plays a role in the modulation of hippocampal long-term plasticity.
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71
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Lutkenhoff E, Karlsgodt KH, Gutman B, Stein JL, Thompson PM, Cannon TD, Jentsch JD. Structural and functional neuroimaging phenotypes in dysbindin mutant mice. Neuroimage 2012; 62:120-9. [PMID: 22584233 DOI: 10.1016/j.neuroimage.2012.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 05/02/2012] [Accepted: 05/05/2012] [Indexed: 12/19/2022] Open
Abstract
Schizophrenia is a highly heritable psychiatric disorder that is associated with a number of structural and functional neurophenotypes. DTNBP1, the gene encoding dysbindin-1, is a promising candidate gene for schizophrenia. Use of a mouse model carrying a large genomic deletion exclusively within the dysbindin gene permits a direct investigation of the gene in isolation. Here, we use manganese-enhanced magnetic resonance imaging (MEMRI) to explore the regional alterations in brain structure and function caused by loss of the gene encoding dysbindin-1. We report novel findings that uniquely inform our understanding of the relationship of dysbindin-1 to known schizophrenia phenotypes. First, in mutant mice, analysis of the rate of manganese uptake into the brain over a 24-hour period, putatively indexing basal cellular activity, revealed differences in dopamine rich brain regions, as well as in CA1 and dentate subregions of the hippocampus formation. Finally, novel tensor-based morphometry techniques were applied to the mouse MRI data, providing evidence for structural volume deficits in cortical regions, subiculum and dentate gyrus, and the striatum of dysbindin mutant mice. The affected cortical regions were primarily localized to the sensory cortices in particular the auditory cortex. This work represents the first application of manganese-enhanced small animal imaging to a mouse model of schizophrenia endophenotypes, and a novel combination of functional and structural measures. It revealed both hypothesized and novel structural and functional neural alterations related to dysbindin-1.
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Affiliation(s)
- Evan Lutkenhoff
- Interdisciplinary Neuroscience Program, University of California, Los Angeles, CA 90095, USA
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72
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O'Tuathaigh CMP, Desbonnet L, Waddington JL. Mutant mouse models in evaluating novel approaches to antipsychotic treatment. Handb Exp Pharmacol 2012:113-45. [PMID: 23027414 DOI: 10.1007/978-3-642-25758-2_5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this review we consider the application of mutant mouse phenotypes to the study of psychotic illness in general and schizophrenia in particular, as they relate to behavioral, psychopharmacological, and cellular phenotypes of putative import for antipsychotic drug development. Mutant models appear to be heuristic at two main levels; firstly, by indicating the functional roles of neuronal components thought to be of relevance to the putative pathobiology of psychotic illness, they help resolve overt behavioral and underlying cellular processes regulated by those neuronal components; secondly, by indicating the functional roles of genes associated with risk for psychotic illness, they help resolve overt behavioral and underlying cellular processes regulated by those risk genes. We focus initially on models of dopaminergic and glutamatergic dysfunction. Then, we consider advances in the genetics of schizophrenia and mutant models relating to replicable risk genes. Lastly, we extend this discussion by exemplifying two new variant approaches in mutant mice that may serve as prototypes for advancing antipsychotic drug development. There is continuing need not only to address numerous technical challenges but also to develop more "real-world" paradigms that reflect the milieu of gene × environment and gene × gene interactions that characterize psychotic illness and its response to antipsychotic drugs.
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Affiliation(s)
- Colm M P O'Tuathaigh
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
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73
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Cellular Mechanisms for the Biogenesis and Transport of Synaptic and Dense-Core Vesicles. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 299:27-115. [DOI: 10.1016/b978-0-12-394310-1.00002-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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74
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Yin DM, Chen YJ, Sathyamurthy A, Xiong WC, Mei L. Synaptic dysfunction in schizophrenia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:493-516. [PMID: 22351070 DOI: 10.1007/978-3-7091-0932-8_22] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Schizophrenia alters basic brain processes of perception, emotion, and judgment to cause hallucinations, delusions, thought disorder, and cognitive deficits. Unlike neurodegeneration diseases that have irreversible neuronal degeneration and death, schizophrenia lacks agreeable pathological hallmarks, which makes it one of the least understood psychiatric disorders. With identification of schizophrenia susceptibility genes, recent studies have begun to shed light on underlying pathological mechanisms. Schizophrenia is believed to result from problems during neural development that lead to improper function of synaptic transmission and plasticity, and in agreement, many of the susceptibility genes encode proteins critical for neural development. Some, however, are also expressed at high levels in adult brain. Here, we will review evidence for altered neurotransmission at glutamatergic, GABAergic, dopaminergic, and cholinergic synapses in schizophrenia and discuss roles of susceptibility genes in neural development as well as in synaptic plasticity and how their malfunction may contribute to pathogenic mechanisms of schizophrenia. We propose that mouse models with precise temporal and spatial control of mutation or overexpression would be useful to delineate schizophrenia pathogenic mechanisms.
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Affiliation(s)
- Dong-Min Yin
- Department of Neurology, Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, GA 30912, USA
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75
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Papaleo F, Yang F, Garcia S, Chen J, Lu B, Crawley JN, Weinberger DR. Dysbindin-1 modulates prefrontal cortical activity and schizophrenia-like behaviors via dopamine/D2 pathways. Mol Psychiatry 2012; 17:85-98. [PMID: 20956979 PMCID: PMC3388848 DOI: 10.1038/mp.2010.106] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Dysbindin-1 regulates D2-receptor trafficking and is implicated in schizophrenia and related cognitive abnormalities, but whether this molecular effect mediates the clinical manifestations of the disorder is unknown. We explored in dysbindin-1-deficient mice (dys-/-) (1) schizophrenia-related behaviors, (2) molecular and electrophysiological changes in medial prefrontal cortex (mPFC) and (3) the dependence of these on D2-receptor stimulation. Dysbindin-1 disruption altered dopamine-related behaviors and impaired working memory under challenging/stressful conditions. Dys-/- pyramidal neurons in mPFC layers II/III were hyperexcitable at baseline but hypoexcitable following D2 stimulation. Dys-/- were also respectively more and less sensitive to D2 agonist- and antagonist-induced behavioral effects. Dys-/- had reduced expression of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and CaMKKβ in mPFC. Chronic D2 agonist treatment reproduced these changes in protein expression, and some of the dys-/- behavioral effects. These results elucidate dysbindin's modulation of D2-related behavior, cortical activity and mPFC CaMK components, implicating cellular and molecular mechanisms of the association of dysbindin with psychosis.
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Affiliation(s)
- F Papaleo
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD 20892, USA.
| | - F Yang
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA,Section on Neural Development and Plasticity, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - S Garcia
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - J Chen
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - B Lu
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
| | - JN Crawley
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, MD, USA
| | - DR Weinberger
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, Bethesda, MD, USA
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76
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Larimore J, Tornieri K, Ryder PV, Gokhale A, Zlatic SA, Craige B, Lee JD, Talbot K, Pare JF, Smith Y, Faundez V. The schizophrenia susceptibility factor dysbindin and its associated complex sort cargoes from cell bodies to the synapse. Mol Biol Cell 2011; 22:4854-67. [PMID: 21998198 PMCID: PMC3237628 DOI: 10.1091/mbc.e11-07-0592] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 09/08/2011] [Accepted: 10/07/2011] [Indexed: 11/11/2022] Open
Abstract
Dysbindin assembles into the biogenesis of lysosome-related organelles complex 1 (BLOC-1), which interacts with the adaptor protein complex 3 (AP-3), mediating a common endosome-trafficking route. Deficiencies in AP-3 and BLOC-1 affect synaptic vesicle composition. However, whether AP-3-BLOC-1-dependent sorting events that control synapse membrane protein content take place in cell bodies upstream of nerve terminals remains unknown. We tested this hypothesis by analyzing the targeting of phosphatidylinositol-4-kinase type II α (PI4KIIα), a membrane protein present in presynaptic and postsynaptic compartments. PI4KIIα copurified with BLOC-1 and AP-3 in neuronal cells. These interactions translated into a decreased PI4KIIα content in the dentate gyrus of dysbindin-null BLOC-1 deficiency and AP-3-null mice. Reduction of PI4KIIα in the dentate reflects a failure to traffic from the cell body. PI4KIIα was targeted to processes in wild-type primary cultured cortical neurons and PC12 cells but failed to reach neurites in cells lacking either AP-3 or BLOC-1. Similarly, disruption of an AP-3-sorting motif in PI4KIIα impaired its sorting into processes of PC12 and primary cultured cortical neuronal cells. Our findings indicate a novel vesicle transport mechanism requiring BLOC-1 and AP-3 complexes for cargo sorting from neuronal cell bodies to neurites and nerve terminals.
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Affiliation(s)
| | - Karine Tornieri
- Department of Cell Biology, Emory University, Atlanta, GA 30322
| | - Pearl V. Ryder
- Department of Cell Biology, Emory University, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Avanti Gokhale
- Department of Cell Biology, Emory University, Atlanta, GA 30322
| | - Stephanie A. Zlatic
- Department of Cell Biology, Emory University, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Branch Craige
- Department of Cell Biology, Emory University, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Joshua D. Lee
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104
| | - Konrad Talbot
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Yoland Smith
- Department of Neurology and Yerkes National Primate Research Center
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University, Atlanta, GA 30322
- Center for Neurodegenerative Disease, Emory University, Atlanta, GA 30322
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77
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Carlson GC, Talbot K, Halene TB, Gandal MJ, Kazi HA, Schlosser L, Phung QH, Gur RE, Arnold SE, Siegel SJ. Dysbindin-1 mutant mice implicate reduced fast-phasic inhibition as a final common disease mechanism in schizophrenia. Proc Natl Acad Sci U S A 2011; 108:E962-70. [PMID: 21969553 PMCID: PMC3203764 DOI: 10.1073/pnas.1109625108] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
DTNBP1 (dystrobrevin binding protein 1) is a leading candidate susceptibility gene in schizophrenia and is associated with working memory capacity in normal subjects. In schizophrenia, the encoded protein dystrobrevin-binding protein 1 (dysbindin-1) is often reduced in excitatory cortical limbic synapses. We found that reduced dysbindin-1 in mice yielded deficits in auditory-evoked response adaptation, prepulse inhibition of startle, and evoked γ-activity, similar to patterns in schizophrenia. In contrast to the role of dysbindin-1 in glutamatergic transmission, γ-band abnormalities in schizophrenia are most often attributed to disrupted inhibition and reductions in parvalbumin-positive interneuron (PV cell) activity. To determine the mechanism underlying electrophysiological deficits related to reduced dysbindin-1 and the potential role of PV cells, we examined PV cell immunoreactivity and measured changes in net circuit activity using voltage-sensitive dye imaging. The dominant circuit impact of reduced dysbindin-1 was impaired inhibition, and PV cell immunoreactivity was reduced. Thus, this model provides a link between a validated candidate gene and an auditory endophenotypes. Furthermore, these data implicate reduced fast-phasic inhibition as a common underlying mechanism of schizophrenia-associated intermediate phenotypes.
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Affiliation(s)
- Gregory C Carlson
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403, USA.
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78
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Xiong W, Liu T, Wang Y, Chen X, Sun L, Guo N, Zheng H, Zheng L, Ruat M, Han W, Zhang CX, Zhou Z. An inhibitory effect of extracellular Ca2+ on Ca2+-dependent exocytosis. PLoS One 2011; 6:e24573. [PMID: 22028769 PMCID: PMC3196490 DOI: 10.1371/journal.pone.0024573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Accepted: 08/14/2011] [Indexed: 11/21/2022] Open
Abstract
Aim Neurotransmitter release is elicited by an elevation of intracellular Ca2+ concentration ([Ca2+]i). The action potential triggers Ca2+ influx through Ca2+ channels which causes local changes of [Ca2+]i for vesicle release. However, any direct role of extracellular Ca2+ (besides Ca2+ influx) on Ca2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG) neurons and chromaffin cells, widely used models for studying vesicle exocytosis. Results Using photolysis of caged Ca2+ and caffeine-induced release of stored Ca2+, we found that extracellular Ca2+ inhibited exocytosis following moderate [Ca2+]i rises (2–3 µM). The IC50 for extracellular Ca2+ inhibition of exocytosis (ECIE) was 1.38 mM and a physiological reduction (∼30%) of extracellular Ca2+ concentration ([Ca2+]o) significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca2+]o. The calcimimetics Mg2+, Cd2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca2+-sensing receptor (CaSR) was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. Conclusion/Significance As an extension of the classic Ca2+ hypothesis of synaptic release, physiological levels of extracellular Ca2+ play dual roles in evoked exocytosis by providing a source of Ca2+ influx, and by directly regulating quantal size and release probability in neuronal cells.
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Affiliation(s)
- Wei Xiong
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Tao Liu
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Yeshi Wang
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xiaowei Chen
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Lei Sun
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Ning Guo
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Hui Zheng
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Lianghong Zheng
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Martial Ruat
- CNRS, UPR9040, Institut de Neurobiologie Alfred Fessard-IFR 2118, Gif sur Yvette, France
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, Agency for Science, Technology, and Research, Singapore, Singapore
| | - Claire Xi Zhang
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
- * E-mail: (ZZ); (CXZ)
| | - Zhuan Zhou
- State Key Laboratory of Biomembrane Engineering and Center for Life Sciences, Institute of Molecular Medicine, Peking University, Beijing, China
- * E-mail: (ZZ); (CXZ)
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79
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Jones CA, Watson DJG, Fone KCF. Animal models of schizophrenia. Br J Pharmacol 2011; 164:1162-94. [PMID: 21449915 PMCID: PMC3229756 DOI: 10.1111/j.1476-5381.2011.01386.x] [Citation(s) in RCA: 532] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/09/2011] [Accepted: 03/12/2011] [Indexed: 12/27/2022] Open
Abstract
Developing reliable, predictive animal models for complex psychiatric disorders, such as schizophrenia, is essential to increase our understanding of the neurobiological basis of the disorder and for the development of novel drugs with improved therapeutic efficacy. All available animal models of schizophrenia fit into four different induction categories: developmental, drug-induced, lesion or genetic manipulation, and the best characterized examples of each type are reviewed herein. Most rodent models have behavioural phenotype changes that resemble 'positive-like' symptoms of schizophrenia, probably reflecting altered mesolimbic dopamine function, but fewer models also show altered social interaction, and learning and memory impairment, analogous to negative and cognitive symptoms of schizophrenia respectively. The negative and cognitive impairments in schizophrenia are resistant to treatment with current antipsychotics, even after remission of the psychosis, which limits their therapeutic efficacy. The MATRICS initiative developed a consensus on the core cognitive deficits of schizophrenic patients, and recommended a standardized test battery to evaluate them. More recently, work has begun to identify specific rodent behavioural tasks with translational relevance to specific cognitive domains affected in schizophrenia, and where available this review focuses on reporting the effect of current and potential antipsychotics on these tasks. The review also highlights the need to develop more comprehensive animal models that more adequately replicate deficits in negative and cognitive symptoms. Increasing information on the neurochemical and structural CNS changes accompanying each model will also help assess treatments that prevent the development of schizophrenia rather than treating the symptoms, another pivotal change required to enable new more effective therapeutic strategies to be developed.
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Affiliation(s)
- C A Jones
- School of Biomedical Sciences, Medical School, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
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80
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Karlsgodt KH, Bachman P, Winkler AM, Bearden CE, Glahn DC. Genetic influence on the working memory circuitry: behavior, structure, function and extensions to illness. Behav Brain Res 2011; 225:610-22. [PMID: 21878355 DOI: 10.1016/j.bbr.2011.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 10/17/2022]
Abstract
Working memory is a highly heritable complex cognitive trait that is critical for a number of higher-level functions. However, the neural substrates of this behavioral phenotype are intricate and it is unknown through what precise biological mechanism variation in working memory is transmitted. In this review we explore different functional and structural components of the working memory circuitry, and the degree to which each of them is contributed to by genetic factors. Specifically, we consider dopaminergic function, glutamatergic function, white matter integrity and gray matter structure all of which provide potential mechanisms for the inheritance of working memory deficits. In addition to discussing the overall heritability of these measures we also address specific genes that may play a role. Each of these heritable components has the potential to uniquely contribute to the working memory deficits observed in genetic disorders, including 22q deletion syndrome, fragile X syndrome, phenylketonuria (PKU), and schizophrenia. By observing the individual contributions of disruptions in different components of the working memory circuitry to behavioral performance, we highlight the concept that there may be many routes to a working memory deficit; even though the same cognitive measure may be a valid endophenotype across different disorders, the underlying cause of, and treatment for, the deficit may differ. This has implications for our understanding of the transmission of working memory deficits in both healthy and disordered populations.
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Affiliation(s)
- Katherine H Karlsgodt
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
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81
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Mullin AP, Gokhale A, Larimore J, Faundez V. Cell biology of the BLOC-1 complex subunit dysbindin, a schizophrenia susceptibility gene. Mol Neurobiol 2011; 44:53-64. [PMID: 21520000 PMCID: PMC3321231 DOI: 10.1007/s12035-011-8183-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 04/12/2011] [Indexed: 11/28/2022]
Abstract
There is growing interest in the biology of dysbindin and its genetic locus (DTNBP1) due to genetic variants associated with an increased risk of schizophrenia. Reduced levels of dysbindin mRNA and protein in the hippocampal formation of schizophrenia patients further support involvement of this locus in disease risk. Here, we discuss phylogenetically conserved dysbindin molecular interactions that define its contribution to the assembly of the biogenesis of lysosome-related organelles complex-1 (BLOC-1). We explore fundamental cellular processes where dysbindin and the dysbindin-containing BLOC-1 complex are implicated. We propose that cellular, tissue, and system neurological phenotypes from dysbindin deficiencies in model genetic organisms, and likely individuals affected with schizophrenia, emerge from abnormalities in few core cellular mechanisms controlled by BLOC-1-dysbindin-containing complex rather than from defects in dysbindin itself.
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Affiliation(s)
- Ariana P Mullin
- Graduate Program in Neuroscience, Emory University, Atlanta, GA, USA
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82
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Altered presynaptic ultrastructure in excitatory hippocampal synapses of mice lacking dystrophins Dp427 or Dp71. Neurobiol Dis 2011; 43:134-41. [DOI: 10.1016/j.nbd.2011.02.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/20/2011] [Accepted: 02/27/2011] [Indexed: 11/13/2022] Open
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83
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Zic2 hypomorphic mutant mice as a schizophrenia model and ZIC2 mutations identified in schizophrenia patients. Sci Rep 2011; 1:16. [PMID: 22355535 PMCID: PMC3216504 DOI: 10.1038/srep00016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 05/23/2011] [Indexed: 12/23/2022] Open
Abstract
ZIC2 is a causal gene for holoprosencephaly and encodes a zinc-finger-type transcriptional regulator. We characterized Zic2kd/+ mice with a moderate (40%) reduction in Zic2 expression. Zic2kd/+ mice showed increased locomotor activity in novel environments, cognitive and sensorimotor gating dysfunctions, and social behavioral abnormalities. Zic2kd/+ brain involved enlargement of the lateral ventricle, thinning of the cerebral cortex and corpus callosum, and decreased number of cholinergic neurons in the basal forebrain. Because these features are reminiscent of schizophrenia, we examined ZIC2 variant-carrying allele frequencies in schizophrenia patients and in controls in the Japanese population. Among three novel missense mutations in ZIC2, R409P was only found in schizophrenia patients, and was located in a strongly conserved position of the zinc finger domain. Mouse Zic2 with the corresponding mutation showed lowered transcription-activating capacity and had impaired target DNA-binding and co-factor-binding capacities. These results warrant further study of ZIC2 in the pathogenesis of schizophrenia.
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84
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Ghiani CA, Dell'Angelica EC. Dysbindin-containing complexes and their proposed functions in brain: from zero to (too) many in a decade. ASN Neuro 2011; 3:e00058. [PMID: 21504412 PMCID: PMC3155195 DOI: 10.1042/an20110010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/18/2011] [Accepted: 04/20/2011] [Indexed: 02/07/2023] Open
Abstract
Dysbindin (also known as dysbindin-1 or dystrobrevin-binding protein 1) was identified 10 years ago as a ubiquitously expressed protein of unknown function. In the following years, the protein and its encoding gene, DTNBP1, have become the focus of intensive research owing to genetic and histopathological evidence suggesting a potential role in the pathogenesis of schizophrenia. In this review, we discuss published results demonstrating that dysbindin function is required for normal physiology of the mammalian central nervous system. In tissues other than brain and in non-neuronal cell types, the protein has been characterized as a stable component of a multi-subunit complex, named BLOC-1 (biogenesis of lysosome-related organelles complex-1), which has been implicated in intracellular protein trafficking and the biogenesis of specialized organelles of the endosomal-lysosomal system. In the brain, however, dysbindin has been proposed to associate into multiple complexes with alternative binding partners, and to play a surprisingly wide variety of functions including transcriptional regulation, neurite and dendritic spine formation, synaptic vesicle biogenesis and exocytosis, and trafficking of glutamate and dopamine receptors. This puzzling array of molecular and functional properties ascribed to the dysbindin protein from brain underscores the need of further research aimed at ascertaining its biological significance in health and disease.
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Key Words
- biogenesis of lysosome-related organelles complex-1 (bloc-1)
- dtnbp1
- dysbindin
- dystrobrevin-binding protein
- schizophrenia
- ap-3, adaptor protein-3
- bloc, biogenesis of lysosome-related organelles complex
- coip, co-immunoprecipitation
- hek-293 cells, human embryonic kidney cells
- hps, hermansky–pudlak syndrome
- jnk, c-jun n-terminal kinase
- ms/ms, tandem mass spectrometry
- rnai, rna interference
- shrna, short-hairpin rna
- sirna, small-interfering rna
- wash, wiskott–aldrich syndrome protein and scar homologue
- vamp-7, vesicle-associated membrane protein 7
- wave, wasp (wiskott–aldrich syndrome protein) verprolin homologous
- y2h, yeast two-hybrid
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Affiliation(s)
- Cristina A Ghiani
- *Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
- †Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
| | - Esteban C Dell'Angelica
- *Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
- ‡Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
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85
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Fatjó-Vilas M, Papiol S, Estrada G, Bombín I, Peralta V, Rosa A, Parellada M, Miret S, Martín M, Lázaro L, Campanera S, Muñoz MJ, Lera-Miguel S, Arias B, Navarro ME, Castro-Fornieles J, Cuesta MJ, Arango C, Fañanás L. Dysbindin-1 gene contributes differentially to early- and adult-onset forms of functional psychosis. Am J Med Genet B Neuropsychiatr Genet 2011; 156B:322-33. [PMID: 21305691 DOI: 10.1002/ajmg.b.31166] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 12/02/2010] [Indexed: 12/11/2022]
Abstract
Dysbindin-1 is a relatively ubiquitous protein in the brain which is involved in the modulation of synaptic homeostasis. The dysbindin-1 gene (DTNBP1) has been associated with schizophrenia and bipolar disorder diagnoses. However, its contribution to the severity of the clinical and neurocognitive expression of these disorders remains controversial. We aimed to explore the association between DTNBP1 and the phenotypes which are more directly linked with the underlying biology, such as age at onset and neurocognitive impairment. The present family sample comprised 894 Caucasian individuals: 268 patients affected by functional psychosis [58% with illness onset before 18 years, mean age at onset (SD): 14.71 (2.10)], 483 parents and 143 siblings. Ten DTNBP1 single nucleotide polymorphisms were genotyped in all individuals and their transmission disequilibrium was tested in relation to: (i) the risk for psychosis; (ii) patients' age at onset; and (iii) familial neurocognitive performance (including IQ estimation and executive functioning). In early-onset families a 5-marker haplotype encompassing exons 2-4 and the surrounding introns was significantly over-transmitted to cases, while in adult-onset families two haplotypes corresponding to the region between introns 4 and 7 were over-transmitted to cases. Estimated IQ was associated with the rs760666 marker in the whole sample, whereas a significant association between executive functioning and the rs2619522 marker appeared in early-onset families. Our findings confirm the role of the dysbindin-1 gene in the risk for functional psychosis and show a differential haplotypic risk pattern in families with early as opposed to adult onset in the affected offspring.
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Affiliation(s)
- Mar Fatjó-Vilas
- Departament de Biologia Animal, Facultat de Biologia, Universitat de Barcelona, Institut de Biomedicina de la Universitat de Barcelona, Centro de Investigación Biomédica en Red de Salud Mental, Spain
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86
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Kobayashi K, Umeda-Yano S, Yamamori H, Takeda M, Suzuki H, Hashimoto R. Correlated alterations in serotonergic and dopaminergic modulations at the hippocampal mossy fiber synapse in mice lacking dysbindin. PLoS One 2011; 6:e18113. [PMID: 21448290 PMCID: PMC3063243 DOI: 10.1371/journal.pone.0018113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 02/25/2011] [Indexed: 01/21/2023] Open
Abstract
Dysbindin-1 (dystrobrevin-binding protein 1, DTNBP1) is one of the promising schizophrenia susceptibility genes. Dysbindin protein is abundantly expressed in synaptic regions of the hippocampus, including the terminal field of the mossy fibers, and this hippocampal expression of dysbindin is strongly reduced in patients with schizophrenia. In the present study, we examined the functional role of dysbindin in hippocampal mossy fiber-CA3 synaptic transmission and its modulation using the sandy mouse, a spontaneous mutant with deletion in the dysbindin gene. Electrophysiological recordings were made in hippocampal slices prepared from adult male sandy mice and their wild-type littermates. Basic properties of the mossy fiber synaptic transmission in the mutant mice were generally normal except for slightly reduced frequency facilitation. Serotonin and dopamine, two major neuromodulators implicated in the pathophysiology of schizophrenia, can potentiate mossy fiber synaptic transmission probably via an increase in cAMP levels. Synaptic potentiation induced by serotonin and dopamine was very variable in magnitude in the mutant mice, with some mice showing prominent enhancement as compared with the wild-type mice. In addition, the magnitude of potentiation induced by these monoamines significantly correlated with each other in the mutant mice, indicating that a subpopulation of sandy mice has marked hypersensitivity to both serotonin and dopamine. While direct activation of the cAMP cascade by forskolin induced robust synaptic potentiation in both wild-type and mutant mice, this forskolin-induced potentaition correlated in magnitude with the serotonin-induced potentiation only in the mutant mice, suggesting a possible change in coupling of receptor activation to downstream signaling. These results suggest that the dysbindin deficiency could be an essential genetic factor that causes synaptic hypersensitivity to dopamine and serotonin. The altered monoaminergic modulation at the mossy fiber synapse could be a candidate pathophysiological basis for impairment of hippocampus-dependent brain functions in schizophrenia.
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87
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Talbot K, Louneva N, Cohen JW, Kazi H, Blake DJ, Arnold SE. Synaptic dysbindin-1 reductions in schizophrenia occur in an isoform-specific manner indicating their subsynaptic location. PLoS One 2011; 6:e16886. [PMID: 21390302 PMCID: PMC3046962 DOI: 10.1371/journal.pone.0016886] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/06/2011] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND An increasing number of studies report associations between variation in DTNBP1, a top candidate gene in schizophrenia, and both the clinical symptoms of the disorder and its cognitive deficits. DTNBP1 encodes dysbindin-1, reduced levels of which have been found in synaptic fields of schizophrenia cases. This study determined whether such synaptic reductions are isoform-specific. METHODOLOGY/PRINCIPAL FINDINGS Using Western blotting of tissue fractions, we first determined the synaptic localization of the three major dysbindin-1 isoforms (A, B, and C). All three were concentrated in synaptosomes of multiple brain areas, including auditory association cortices in the posterior half of the superior temporal gyrus (pSTG) and the hippocampal formation (HF). Tests on the subsynaptic tissue fractions revealed that each isoform is predominantly, if not exclusively, associated with synaptic vesicles (dysbindin-1B) or with postsynaptic densities (dysbindin-1A and -1C). Using Western blotting on pSTG (n = 15) and HF (n = 15) synaptosomal fractions from schizophrenia cases and their matched controls, we discovered that synaptic dysbindin-1 is reduced in an isoform-specific manner in schizophrenia without changes in levels of synaptophysin or PSD-95. In pSTG, about 92% of the schizophrenia cases displayed synaptic dysbindin-1A reductions averaging 48% (p = 0.0007) without alterations in other dysbindin-1 isoforms. In the HF, by contrast, schizophrenia cases displayed normal levels of synaptic dysbindin-1A, but 67% showed synaptic reductions in dysbindin-1B averaging 33% (p = 0.0256), while 80% showed synaptic reductions in dysbindin-1C averaging 35% (p = 0.0171). CONCLUSIONS/SIGNIFICANCE Given the distinctive subsynaptic localization of dysbindin-1A, -1B, and -1C across brain regions, the observed pSTG reductions in dysbindin-1A are postsynaptic and may promote dendritic spine loss with consequent disruption of auditory information processing, while the noted HF reductions in dysbindin-1B and -1C are both presynaptic and postsynaptic and could promote deficits in spatial working memory.
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Affiliation(s)
- Konrad Talbot
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
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88
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Wolf C, Jackson MC, Kissling C, Thome J, Linden DE. Dysbindin-1 genotype effects on emotional working memory. Mol Psychiatry 2011; 16:145-55. [PMID: 20010894 PMCID: PMC3044452 DOI: 10.1038/mp.2009.129] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 10/15/2009] [Accepted: 11/03/2009] [Indexed: 01/03/2023]
Abstract
We combined functional imaging and genetics to investigate the behavioral and neural effects of a dysbindin-1 (DTNBP1) genotype associated with the expression level of this important synaptic protein, which has been implicated in schizophrenia. On a working memory (WM) task for emotional faces, participants with the genotype related to increased expression showed higher WM capacity for happy faces compared with the genotype related to lower expression. Activity in several task-related brain areas with known DTNBP1 expression was increased, including hippocampal, temporal and frontal cortex. Although these increases occurred across emotions, they were mostly observed in areas whose activity correlated with performance for happy faces. This suggests effects of variability in DTNBP1 on emotion-specific WM capacity and region-specific task-related brain activation in humans. Synaptic effects of DTNBP1 implicate that altered dopaminergic and/or glutamatergic neurotransmission may be related to the increased WM capacity. The combination of imaging and genetics thus allows us to bridge the gap between the cellular/molecular and systems/behavioral level and extend the cognitive neuroscience approach to a comprehensive biology of cognition.
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Affiliation(s)
- Claudia Wolf
- Wolfson Centre for Cognitive and Clinical Neuroscience, School of Psychology, Bangor University, Brigantia Building, Bangor, LL57 2AS, UK
| | - Margaret C. Jackson
- Wolfson Centre for Cognitive and Clinical Neuroscience, School of Psychology, Bangor University, Brigantia Building, Bangor, LL57 2AS, UK
| | - Christian Kissling
- Laboratory of Molecular Psychiatry and Pharmacology, Institute of Life Science, School of Medicine, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Johannes Thome
- Laboratory of Molecular Psychiatry and Pharmacology, Institute of Life Science, School of Medicine, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - David E.J. Linden
- Wolfson Centre for Cognitive and Clinical Neuroscience, School of Psychology, Bangor University, Brigantia Building, Bangor, LL57 2AS, UK
- North Wales Clinical School, Bangor University, Bangor, LL57 2AS, UK
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89
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Lu L, Mamiya T, Koseki T, Mouri A, Nabeshima T. Genetic Animal Models of Schizophrenia Related with the Hypothesis of Abnormal Neurodevelopment. Biol Pharm Bull 2011; 34:1358-63. [DOI: 10.1248/bpb.34.1358] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Lingling Lu
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institute, Meijo University
- Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University
| | - Takayoshi Mamiya
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institute, Meijo University
- Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University
- Japanese Drug Organization for Appropriate Use and Research
| | - Takenao Koseki
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institute, Meijo University
- Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University
| | - Akihiro Mouri
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institute, Meijo University
- Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University
- Japanese Drug Organization for Appropriate Use and Research
| | - Toshitaka Nabeshima
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institute, Meijo University
- Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University
- Japanese Drug Organization for Appropriate Use and Research
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90
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Karlsgodt KH, Robleto K, Trantham-Davidson H, Jairl C, Cannon TD, Lavin A, Jentsch JD. Reduced dysbindin expression mediates N-methyl-D-aspartate receptor hypofunction and impaired working memory performance. Biol Psychiatry 2011; 69:28-34. [PMID: 21035792 PMCID: PMC4204919 DOI: 10.1016/j.biopsych.2010.09.012] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/13/2010] [Accepted: 09/07/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Schizophrenia is a heritable disorder associated with disrupted neural transmission and dysfunction of brain systems involved in higher cognition. The gene encoding dystrobrevin-binding-protein-1 (dysbindin) is a putative candidate gene associated with cognitive impairments, including memory deficits, in both schizophrenia patients and unaffected individuals. The underlying mechanism is thought to be based in changes in glutamatergic and dopaminergic function within the corticostriatal networks known to be critical for schizophrenia. This hypothesis derives support from studies of mice with a null mutation in the dysbindin gene that exhibit memory dysfunction and excitatory neurotransmission abnormalities in prefrontal and hippocampal networks. At a cellular level, dysbindin is thought to mediate presynaptic glutamatergic transmission. METHODS We investigated the relationship between glutamate receptor dynamics and memory performance in dysbindin mutant mice. We assessed N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor function in prefrontal cortex pyramidal neurons in vitro with whole-cell recordings, molecular quantitative analyses (reverse transcription-polymerase chain reaction) of the mandatory NMDA receptor subunit NR1, and cognitive function with a spatial working memory task. RESULTS Decreases in dysbindin are associated with specific decreases in NMDA-evoked currents in prefrontal pyramidal neurons, as well as decreases in NR1 expression. Furthermore, the degree of NR1 expression correlates with spatial working memory performance, providing a mechanistic explanation for cognitive changes previously associated with dysbindin expression. CONCLUSIONS These data show a significant downregulation of NMDA receptors due to dysbindin deficiency and illuminate molecular mechanisms mediating the association between dysbindin insufficiency and cognitive impairments associated with schizophrenia, encouraging study of the dysbindin/NR1 expression association in humans with schizophrenia.
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Affiliation(s)
- Katherine H Karlsgodt
- Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California, USA
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91
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Balu DT, Coyle JT. Neuroplasticity signaling pathways linked to the pathophysiology of schizophrenia. Neurosci Biobehav Rev 2011; 35:848-70. [PMID: 20951727 PMCID: PMC3005823 DOI: 10.1016/j.neubiorev.2010.10.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 10/06/2010] [Accepted: 10/10/2010] [Indexed: 12/15/2022]
Abstract
Schizophrenia is a severe mental illness that afflicts nearly 1% of the world's population. One of the cardinal pathological features of schizophrenia is perturbation in synaptic connectivity. Although the etiology of schizophrenia is unknown, it appears to be a developmental disorder involving the interaction of a potentially large number of risk genes, with no one gene producing a strong effect except rare, highly penetrant copy number variants. The purpose of this review is to detail how putative schizophrenia risk genes (DISC-1, neuregulin/ErbB4, dysbindin, Akt1, BDNF, and the NMDA receptor) are involved in regulating neuroplasticity and how alterations in their expression may contribute to the disconnectivity observed in schizophrenia. Moreover, this review highlights how many of these risk genes converge to regulate common neurotransmitter systems and signaling pathways. Future studies aimed at elucidating the functions of these risk genes will provide new insights into the pathophysiology of schizophrenia and will likely lead to the nomination of novel therapeutic targets for restoring proper synaptic connectivity in the brain in schizophrenia and related disorders.
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Affiliation(s)
- Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
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92
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Johnstone M, Thomson PA, Hall J, McIntosh AM, Lawrie SM, Porteous DJ. DISC1 in schizophrenia: genetic mouse models and human genomic imaging. Schizophr Bull 2011; 37:14-20. [PMID: 21149852 PMCID: PMC3004186 DOI: 10.1093/schbul/sbq135] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Schizophrenia and related disorders have a major genetic component. Several large-scale studies have uncovered a number of possible candidate genes, but these have yet to be consistently replicated and their underlying biological function remains elusive. One exception is 'Disrupted in schizophrenia 1' (DISC1), a gene locus originally identified in a large Scottish family, showing a heavy burden of major mental illnesses associated with a balanced t(1;11)(q42.1;q14.3) chromosome translocation. Substantial genetic and biological research on DISC1 has been reported in the intervening 10 years: DISC1 is now recognized as a genetic risk factor for a spectrum of psychiatric disorders and DISC1 impacts on many aspects of central nervous system (CNS) function, including neurodevelopment, neurosignaling, and synaptic functioning. Evidence has emerged from genetic studies showing a relationship between DISC1 and quantitative traits, including working memory, cognitive aging, gray matter volume in the prefrontal cortex, and abnormalities in hippocampal structures and function. DISC1 interacts with numerous proteins also involved in neuronal migration, neurite outgrowth, cytoskeletal modulation, and signal transduction, some of which have been reported as independent genetic susceptibility factors for psychiatric morbidity. Here, we focus on the growing literature relating genetic variation in the DISC1 pathway to functional and structural studies of the brain in humans and in the mouse.
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Affiliation(s)
- Mandy Johnstone
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Pippa A. Thomson
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Jeremy Hall
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Andrew M. McIntosh
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Stephen M. Lawrie
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
| | - David J. Porteous
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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93
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Zhang JP, Burdick KE, Lencz T, Malhotra AK. Meta-analysis of genetic variation in DTNBP1 and general cognitive ability. Biol Psychiatry 2010; 68:1126-33. [PMID: 21130223 PMCID: PMC3026311 DOI: 10.1016/j.biopsych.2010.09.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 07/30/2010] [Accepted: 09/06/2010] [Indexed: 01/31/2023]
Abstract
BACKGROUND The human dystrobrevin binding protein 1 (DTNBP1) gene has been linked to risk for schizophrenia. Recent studies indicate that several single nucleotide polymorphisms (SNPs) in the DTNBP1 gene may also influence general cognitive ability in both schizophrenic patients and healthy control subjects. We examined the relationship between DTNBP1 SNPs and general cognitive ability in nonpsychiatric healthy samples via meta-analysis. METHODS MEDLINE search (12/31/09) yielded 11 articles examining DTNBP1 variation and general cognitive ability, of which 8 studies had data available encompassing 10 independent cohorts (total n = 7592). The phenotype was defined as either the first principal component score from multiple neuropsychological tests (Spearman's g) or full-scale IQ. Meta-analyses were conducted for nine SNPs for which cognitive data were available from at least three cohorts. For each SNP in each cohort, effect size was computed between major allele homozygotes and minor allele carriers; effect size was then pooled across studies using a random effect model. RESULTS Pooled effect sizes from two of the nine SNPs (rs1018381 and rs2619522) were -.123 and -.083, ps < .01, respectively, suggesting that the minor allele carriers of these SNPs had lower cognitive ability scores than the major allele homozygotes. Results remained significant after examining heterogeneity among samples and potential publication biases. Other SNPs did not show significant effects on general cognitive ability. CONCLUSIONS Genetic variation in DTNBP1 modestly influences general cognitive ability. Further studies are needed to elucidate the biological mechanisms that may account for this relationship.
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Affiliation(s)
| | - Katherine E. Burdick
- Division of Psychiatry Research, The Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, NY, Center for Psychiatric Neurosciences, Feinstein Institute for Medical Research, Manhasset, NY, Department of Psychiatry and Behavioral Science, Albert Einstein College of Medicine, Bronx, NY
| | - Todd Lencz
- Division of Psychiatry Research, The Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, NY, Center for Psychiatric Neurosciences, Feinstein Institute for Medical Research, Manhasset, NY, Department of Psychiatry and Behavioral Science, Albert Einstein College of Medicine, Bronx, NY, Department of Psychiatry, Hofstra University School of Medicine, Hempstead, NY
| | - Anil K. Malhotra
- Division of Psychiatry Research, The Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, NY, Center for Psychiatric Neurosciences, Feinstein Institute for Medical Research, Manhasset, NY, Department of Psychiatry and Behavioral Science, Albert Einstein College of Medicine, Bronx, NY
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94
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Fei E, Ma X, Zhu C, Xue T, Yan J, Xu Y, Zhou J, Wang G. Nucleocytoplasmic shuttling of dysbindin-1, a schizophrenia-related protein, regulates synapsin I expression. J Biol Chem 2010; 285:38630-40. [PMID: 20921223 PMCID: PMC2992295 DOI: 10.1074/jbc.m110.107912] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 09/23/2010] [Indexed: 01/29/2023] Open
Abstract
Dysbindin-1 is a 50-kDa coiled-coil-containing protein encoded by the gene DTNBP1 (dystrobrevin-binding protein 1), a candidate genetic factor for schizophrenia. Genetic variations in this gene confer a susceptibility to schizophrenia through a decreased expression of dysbindin-1. It was reported that dysbindin-1 regulates the expression of presynaptic proteins and the release of neurotransmitters. However, the precise functions of dysbindin-1 are largely unknown. Here, we show that dysbindin-1 is a novel nucleocytoplasmic shuttling protein and translocated to the nucleus upon treatment with leptomycin B, an inhibitor of exportin-1/CRM1-mediated nuclear export. Dysbindin-1 harbors a functional nuclear export signal necessary for its nuclear export, and the nucleocytoplasmic shuttling of dysbindin-1 affects its regulation of synapsin I expression. In brains of sandy mice, a dysbindin-1-null strain that displays abnormal behaviors related to schizophrenia, the protein and mRNA levels of synapsin I are decreased. These findings demonstrate that the nucleocytoplasmic shuttling of dysbindin-1 regulates synapsin I expression and thus may be involved in the pathogenesis of schizophrenia.
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MESH Headings
- Active Transport, Cell Nucleus/drug effects
- Active Transport, Cell Nucleus/genetics
- Animals
- Antibiotics, Antineoplastic/pharmacology
- Brain/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cytoplasm/genetics
- Cytoplasm/metabolism
- Dysbindin
- Dystrophin-Associated Proteins
- Fatty Acids, Unsaturated/pharmacology
- Gene Expression Regulation
- HEK293 Cells
- Humans
- Karyopherins/antagonists & inhibitors
- Karyopherins/genetics
- Karyopherins/metabolism
- Mice
- Mice, Mutant Strains
- Presynaptic Terminals/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Schizophrenia/genetics
- Schizophrenia/metabolism
- Synapsins/biosynthesis
- Synapsins/genetics
- Exportin 1 Protein
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Affiliation(s)
- Erkang Fei
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Xiaochuan Ma
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Cuiqing Zhu
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ting Xue
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Jie Yan
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yuxia Xu
- the State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jiangning Zhou
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
| | - Guanghui Wang
- From the Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China and
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95
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Evaluating the effects of immunotoxicants using carbon fiber microelectrode amperometry. Anal Bioanal Chem 2010; 398:2979-85. [DOI: 10.1007/s00216-010-4263-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 09/24/2010] [Accepted: 09/28/2010] [Indexed: 11/25/2022]
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96
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Abstract
Genetic variations in dysbindin-1 (dystrobrevin-binding protein-1) are one of the most commonly reported variations associated with schizophrenia. As schizophrenia could be regarded as a neurodevelopmental disorder resulting from abnormalities of synaptic connectivity, we attempted to clarify the function of dysbindin-1 in neuronal development. We examined the developmental change of dysbindin-1 in rat brain by western blotting and found that a 50 kDa isoform is highly expressed during the embryonic stage, whereas a 40 kDa one is detected at postnatal day 11 and increased thereafter. Immunofluorescent analyses revealed that dysbindin-1 is enriched at the spine-like structure of primary cultured rat hippocampal neurons. We identified WAVE2, but not N-WASP, as a binding partner for dysbindin-1. We also found that Abi-1, a binding molecule for WAVE2 involved in spine morphogenesis, interacts with dysbindin-1. Although dysbindin-1, WAVE2 and Abi-1 form a ternary complex, dysbindin-1 promoted the binding of WAVE2 to Abi-1. RNA interference-mediated knockdown of dysbindin-1 led to the generation of abnormally elongated immature dendritic protrusions. The present results indicate possible functions of dysbindin-1 at the postsynapse in the regulation of dendritic spine morphogenesis through the interaction with WAVE2 and Abi-1.
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97
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Wilson C, Terry AV. Neurodevelopmental animal models of schizophrenia: role in novel drug discovery and development. ACTA ACUST UNITED AC 2010; 4:124-37. [PMID: 20643635 DOI: 10.3371/csrp.4.2.4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Schizophrenia is a devastating mental illness that is associated with a lifetime of disability. For patients to successfully function in society, the amelioration of disease symptoms is imperative. The recently published results of two large antipsychotic clinical trials (e.g., CATIE, CUtLASS) clearly exemplified the limitations of currently available treatment options for schizophrenia, and further highlighted the critical need for novel drug discovery and development in this field. One of the biggest challenges in schizophrenia-related drug discovery is to find an appropriate animal model of the illness so that novel hypotheses can be tested at the basic science level. A number of pharmacological, genetic, and neurodevelopmental models have been introduced; however, none of these models has been rigorously evaluated for translational relevance or to satisfy requirements of "face," "construct" and "predictive" validity. Given the apparent polygenic nature of schizophrenia and the limited translational significance of pharmacological models, neurodevelopmental models may offer the best chance of success. The purpose of this review is to provide a general overview of the various neurodevelopmental models of schizophrenia that have been introduced to date, and to summarize their behavioral and neurochemical phenotypes that may be useful from a drug discovery and development standpoint. While it may be that, in the final analysis, no single animal model will satisfy all the requirements necessary for drug discovery purposes, several of the models may be useful for modeling various phenomenological and pathophysiological components of schizophrenia that could be targeted independently with separate molecules or multi-target drugs.
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Affiliation(s)
- Christina Wilson
- Department of Pharmacology and Toxicology, School of Graduate Studies, Medical College of Georgia, Augusta, GA 30912-2300, USA
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98
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Abstract
Homeostatic synaptic plasticity is a negative feedback mechanism that neurons use to offset excessive excitation or inhibition by adjusting their synaptic strengths. Recent findings reveal a complex web of signaling processes involved in this compensatory form of synaptic strength regulation, and in contrast to the popular view of homeostatic plasticity as a slow, global phenomenon, neurons may also rapidly tune the efficacy of individual synapses on demand. Here we review our current understanding of cellular and molecular mechanisms of homeostatic synaptic plasticity.
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Affiliation(s)
- Karine Pozo
- MRC Cell Biology Unit and MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
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99
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Pócsai K, Bagyura Z, Kálmán M. Components of the basal lamina and dystrophin-dystroglycan complex in the neurointermediate lobe of rat pituitary gland: different localizations of beta-dystroglycan, dystrobrevins, alpha1-syntrophin, and aquaporin-4. J Histochem Cytochem 2010; 58:463-79. [PMID: 20124096 PMCID: PMC2857818 DOI: 10.1369/jhc.2010.954768] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 01/21/2010] [Indexed: 11/22/2022] Open
Abstract
The so-called neurointermediate lobe is composed of the intermediate and neural lobes of the pituitary. The present immunohistochemical study investigated components of the basal lamina (laminin, agrin, and perlecan), the dystrophin-dystroglycan complex (dystrophin, beta-dystroglycan, alpha1-dystrobrevin, beta-dystrobrevin, utrophin, and alpha1-syntrophin), and the aquaporins (aquaporin-4 and -9). Glia markers (GFAP, S100, and glutamine synthetase) and components of connective tissue (collagen type I and fibronectin) were also labeled. In the neurohypophysis, immunostaining of basal lamina delineated meningeal invaginations. In these invaginations, vessels were seen to penetrate the organ without submerging into its parenchyma. On the parenchymal side of the invaginations, beta-dystroglycan was detected, whereas utrophin was detected in the walls of vessels. Immunostaining of alpha1-dystrobrevin and alpha1-syntrophin did not delineate the vessels. The cells of the intermediate lobe were fully immunoreactive to alpha1-dystrobrevin and alpha1-syntrophin, whereas components of the basal lamina delineated the contours of the cells. GFAP-immunoreactive processes surrounded them. Aquaporin-4 localized at the periphery of the neurohypophysis, mainly adjacent to the intermediate lobe but not along the vessels. It colocalized only partially with GFAP and not at all with alpha1-syntrophin. Aquaporin-9 was not detected. These results emphasize the possibility that the components of the dystrophin-dystroglycan complex localize differently and raise the question about the roles of dystrobrevins, alpha1-syntrophin, and aquaporin-4 in the functions of the intermediate and neural lobes, respectively.
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Affiliation(s)
- Károly Pócsai
- Department of Anatomy, Histology and Embryology, Semmelweis University, Tuzoltó 58, Budapest, H-1094, Hungary
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100
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Mead CLR, Kuzyk MA, Moradian A, Wilson GM, Holt RA, Morin GB. Cytosolic protein interactions of the schizophrenia susceptibility gene dysbindin. J Neurochem 2010; 113:1491-503. [PMID: 20236384 DOI: 10.1111/j.1471-4159.2010.06690.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Using immunoprecipitation, mass spectrometry, and western blot analysis we investigated cytosolic protein interactions of the schizophrenia susceptibility gene dysbindin in mammalian cells. We identified novel interactions with members of the exocyst, dynactin and chaperonin containing T-complex protein complexes, and we confirmed interactions reported previously with all members of the biogenesis of lysosome-related organelles complex-1 and the adaptor-related protein complex 3. We report interactions between dysbindin and the exocyst and dynactin complex that confirm a link between two important schizophrenia susceptibility genes: dysbindin and disrupted-in-schizophrenia-1. To expand upon this network of interacting proteins we also investigated protein interactions for members of the exocyst and dynactin complexes in mammalian cells. Our results are consistent with the notion that impairment of aspects of the synaptic vesicle life cycle may be a pathogenic mechanism in schizophrenia.
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Affiliation(s)
- Carri-Lyn R Mead
- Michael Smith Genome Sciences Centre, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada
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