ORCID Profile
0000-0001-8732-8735
Current Organisations
Genes to Cognition international consortium
,
The University of Edinburgh
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Publisher: Wiley
Date: 20-04-2015
DOI: 10.1111/MEC.13161
Abstract: Chromosomal inversion polymorphisms are common in animals and plants, and recent models suggest that alternative arrangements spread by capturing different combinations of alleles acting additively or epistatically to favour local adaptation. It is also thought that inversions typically maintain favoured combinations for a long time by suppressing recombination between alternative chromosomal arrangements. Here, we consider patterns of linkage disequilibrium and genetic ergence in an old inversion polymorphism in Drosophila melanogaster (In(3R)Payne) known to be associated with climate change adaptation and a recent invasion event into Australia. We extracted, karyotyped and sequenced whole chromosomes from two Australian populations, so that changes in the arrangement of the alleles between geographically separated tropical and temperate areas could be compared. Chromosome-wide linkage disequilibrium (LD) analysis revealed strong LD within the region spanned by In(3R)Payne. This genomic region also showed strong differentiation between the tropical and the temperate populations, but no differentiation between different karyotypes from the same population, after controlling for chromosomal arrangement. Patterns of differentiation across the chromosome arm and in gene ontologies were enhanced by the presence of the inversion. These data support the notion that inversions are strongly selected by bringing together combinations of genes, but it is still not clear if such combinations act additively or epistatically. Our data suggest that climatic adaptation through inversions can be dynamic, reflecting changes in the relative abundance of different forms of an inversion and ongoing evolution of allelic content within an inversion.
Publisher: EMBO
Date: 2009
DOI: 10.1038/MSB.2009.27
Publisher: Springer Science and Business Media LLC
Date: 02-03-2017
DOI: 10.1038/NCOMMS14613
Abstract: The proteome of human brain synapses is highly complex and is mutated in over 130 diseases. This complexity arose from two whole-genome duplications early in the vertebrate lineage. Zebrafish are used in modelling human diseases however, its synapse proteome is uncharacterized, and whether the teleost-specific genome duplication (TSGD) influenced complexity is unknown. We report the characterization of the proteomes and ultrastructure of central synapses in zebrafish and analyse the importance of the TSGD. While the TSGD increases overall synapse proteome complexity, the postsynaptic density (PSD) proteome of zebrafish has lower complexity than mammals. A highly conserved set of ∼1,000 proteins is shared across vertebrates. PSD ultrastructural features are also conserved. Lineage-specific proteome differences indicate that vertebrate species evolved distinct synapse types and functions. The data sets are a resource for a wide range of studies and have important implications for the use of zebrafish in modelling human synaptic diseases.
Publisher: Rockefeller University Press
Date: 18-11-2002
Abstract: Voltage-dependent potassium channels regulate membrane excitability and cell–cell communication in the mammalian nervous system, and are found highly localized at distinct neuronal subcellular sites. Kv1 (mammalian Shaker family) potassium channels and the neurexin Caspr2, both of which contain COOH-terminal PDZ domain binding peptide motifs, are found colocalized at high density at juxtaparanodes flanking nodes of Ranvier of myelinated axons. The PDZ domain–containing protein PSD-95, which clusters Kv1 potassium channels in heterologous cells, has been proposed to play a major role in potassium channel clustering in mammalian neurons. Here, we show that PSD-95 colocalizes precisely with Kv1 potassium channels and Caspr2 at juxtaparanodes, and that a macromolecular complex of Kv1 channels and PSD-95 can be immunopurified from mammalian brain and spinal cord. Surprisingly, we find that the high density clustering of Kv1 channels and Caspr2 at juxtaparanodes is normal in a mutant mouse lacking juxtaparanodal PSD-95, and that the indirect interaction between Kv1 channels and Caspr2 is maintained in these mutant mice. These data suggest that the primary function of PSD-95 at juxtaparanodes lies outside of its accepted role in mediating the high density clustering of Kv1 potassium channels at these sites.
Publisher: Cold Spring Harbor Laboratory
Date: 18-03-2022
DOI: 10.1101/2022.03.16.484431
Abstract: Complex wiring between neurons underlies the information-processing network enabling all brain functions, including cognition and memory. For understanding how the network is structured, processes information, and changes over time, comprehensive visualization of the architecture of living brain tissue with its cellular and molecular components would open up major opportunities. However, electron microscopy (EM) provides nanometre-scale resolution required for full in-silico reconstruction 1–5 , yet is limited to fixed specimens and static representations. Light microscopy allows live observation, with super-resolution approaches 6–12 facilitating nanoscale visualization, but comprehensive 3D-reconstruction of living brain tissue has been hindered by tissue photo-burden, photobleaching, insufficient 3D-resolution, and inadequate signal-to-noise ratio (SNR). Here we demonstrate saturated reconstruction of living brain tissue. We developed an integrated imaging and analysis technology, adapting stimulated emission depletion (STED) microscopy 6,13 in extracellularly labelled tissue 14 for high SNR and near-isotropic resolution. Centrally, a two-stage deep-learning approach leveraged previously obtained information on s le structure to drastically reduce photo-burden and enable automated volumetric reconstruction down to single synapse level. Live reconstruction provides unbiased analysis of tissue architecture across time in relation to functional activity and targeted activation, and contextual understanding of molecular labelling. This adoptable technology will facilitate novel insights into the dynamic functional architecture of living brain tissue.
Publisher: Elsevier BV
Date: 08-2017
Publisher: Society for Neuroscience
Date: 03-06-2009
DOI: 10.1523/JNEUROSCI.1090-09.2009
Abstract: Here, we report that postsynaptic density protein of 95 kDa (PSD-95), a postsynaptic density scaffolding protein, classically conceptualized as being essential for the regulation of ionotropic glutamatergic signaling at the postsynaptic membrane, plays an unanticipated and essential role in mediating the actions of hallucinogens and atypical antipsychotic drugs at 5-HT 2A and 5-HT 2C serotonergic G-protein-coupled receptors. We show that PSD-95 is crucial for normal 5-HT 2A and 5-HT 2C expression in vivo and that PSD-95 maintains normal receptor expression by promoting apical dendritic targeting and stabilizing receptor turnover in vivo . Significantly, 5-HT 2A - and 5-HT 2C -mediated downstream signaling is impaired in PSD-95 null mice, and the 5-HT 2A -mediated head-twitch response is abnormal. Furthermore, the ability of 5-HT 2A inverse agonists to normalize behavioral changes induced by glutamate receptor antagonists is abolished in the absence of PSD-95 in vivo . These results demonstrate that PSD-95, in addition to the well known role it plays in scaffolding macromolecular glutamatergic signaling complexes, profoundly modulates metabotropic 5-HT 2A and 5-HT 2C receptor function.
Publisher: Springer Netherlands
Date: 2007
DOI: 10.1007/978-1-4020-5943-8_9
Abstract: It is now apparent that multiprotein signalling complexes or "signalling machines" are responsible for orchestrating many complex signalling pathways in the cell. The synapse is a sub-cellular specialisation which transmits and converts patterns of electrical activity into cellular memory. This processing of electrical information is mediated by the protein components of the synapse. The organisation of synaptic proteins has been investigated over the last number of years using proteomic methods and with the application ofbioinformatics a landscape of modular protein complexes at the synapse is emerging. Many share a common organisation centred on a receptor/channel, a protein scaffold, (in which the signalling molecules are localised) and membrane to cytoskeleton interactions. The use of PDZ-domain based protein scaffolds is a particularly common feature in the construction of neuronal protein complexes and the differential presence of these proteins in complexes can have functional consequences. Here we overview current proteomic methodologies for the analysis of multiprotein complexes. In addition, we describe the characterisation of a number of multiprotein complexes associated with ion channels (NMDAR, P2X7 and Kir2) and GPCRs (5-HT2A/5-HT2C, D2 and mGluR5) and discuss common their common components and organisation.
Publisher: Cold Spring Harbor Laboratory
Date: 12-07-2018
DOI: 10.1101/363614
Abstract: In recent years, the remarkable molecular complexity of synapses has been revealed, with over 1000 proteins identified in the synapse proteome. Although it is known that different receptors and other synaptic proteins are present in different types of neurons and synapses, the extent of synapse ersity across the brain is largely unknown, mainly owing to technical limitations. Combining mouse genetics and proteomics we have previously reported highly efficient methods for purification of synaptic protein complexes under native conditions. In that approach, tandem affinity purification (TAP) tags were fused to the carboxyl terminus of PSD95 using gene targeting in mice. Here we report an approach that restricts tagging of endogenous PSD95 to cells expressing Cre recombinase. In addition, we developed a labelling strategy enabling visualization of endogenous PSD95 tagged by fluorescent proteins in Cre-expressing cells. We demonstrate the feasibility of proteomic characterisation of synapse proteomes and visualization of synapse proteins in specific cell types. We find that composition of PSD95 complexes purified from specific cell types differs from those extracted from tissues with erse cellular composition. Therefore, these novel conditional PSD95 tagging lines will not only serve as powerful tools for precisely dissecting synapse ersity in specific subsets of regions/neuronal cells, but also provide an opportunity to better understand brain region-specific alterations associated with various psychiatric/neurological diseases. The newly developed conditional gene tagging methods can be applied to many different synaptic proteins and will thus facilitate research on the molecular complexity of synapses.
Publisher: Society for Neuroscience
Date: 22-09-2010
DOI: 10.1523/JNEUROSCI.0896-10.2010
Abstract: Neuroligins are postsynaptic cell adhesion molecules that associate with presynaptic neurexins. Both factors form a transsynaptic connection, mediate signaling across the synapse, specify synaptic functions, and play a role in synapse formation. Neuroligin dysfunction impairs synaptic transmission, disrupts neuronal networks, and is thought to participate in cognitive diseases. Here we report that chemical treatment designed to induce long-term potentiation or long-term depression (LTD) induces neuroligin 1/3 turnover, leading to either increased or decreased surface membrane protein levels, respectively. Despite its structural role at a crucial transsynaptic position, GFP-neuroligin 1 leaves synapses in hippoc al neurons over time with chemical LTD-induced neuroligin internalization depending on an intact microtubule cytoskeleton. Accordingly, neuroligin 1 and its binding partner postsynaptic density protein-95 (PSD-95) associate with components of the dynein motor complex and undergo retrograde cotransport with a dynein subunit. Transgenic depletion of dynein function in mice causes postsynaptic NLG1/3 and PSD-95 enrichment. In parallel, PSD lengths and spine head sizes are significantly increased, a phenotype similar to that observed upon transgenic overexpression of NLG1 (Dahlhaus et al., 2010). Moreover, application of a competitive PSD-95 peptide and neuroligin 1 C-terminal mutagenesis each specifically alter neuroligin 1 surface membrane expression and interfere with its internalization. Our data suggest the concept that synaptic plasticity regulates neuroligin turnover through active cytoskeleton transport.
Publisher: Oxford University Press
Date: 07-2013
DOI: 10.1093/MED/9780199934959.003.0024
Abstract: Human synapses contain over 1000 proteins forming the synapse proteome and diseases that disrupt these proteins cause synaptopathy. Hundreds of gene mutations in synapse proteins cause over 130 brain diseases including major psychiatric, neurological and childhood developmental disorders. The synapse proteome is organized into the presynaptic and postsynaptic proteome and each is further organized into macromolecular multiprotein complexes that perform key functions. Disruption of these complexes underlies a common etiology of diseases with related clinical features such as Schizophrenia, Autism and Intellectual Disability. Mutations in the different genes encoding the proteins comprising these complexes also underlies the multigenic nature of diseases. Synaptic disease is emerging as a major cause of brain disease and understanding the organization and function of the synapse proteome opens important new avenues for disease classification and therapeutic intervention.
Publisher: Public Library of Science (PLoS)
Date: 20-12-2006
Publisher: Springer Science and Business Media LLC
Date: 10-07-2023
DOI: 10.1038/S41592-023-01936-6
Abstract: Three-dimensional (3D) reconstruction of living brain tissue down to an in idual synapse level would create opportunities for decoding the dynamics and structure–function relationships of the brain’s complex and dense information processing network however, this has been hindered by insufficient 3D resolution, inadequate signal-to-noise ratio and prohibitive light burden in optical imaging, whereas electron microscopy is inherently static. Here we solved these challenges by developing an integrated optical/machine-learning technology, LIONESS (live information-optimized nanoscopy enabling saturated segmentation). This leverages optical modifications to stimulated emission depletion microscopy in comprehensively, extracellularly labeled tissue and previous information on s le structure via machine learning to simultaneously achieve isotropic super-resolution, high signal-to-noise ratio and compatibility with living tissue. This allows dense deep-learning-based instance segmentation and 3D reconstruction at a synapse level, incorporating molecular, activity and morphodynamic information. LIONESS opens up avenues for studying the dynamic functional (nano-)architecture of living brain tissue.
Publisher: Wiley
Date: 31-03-2006
Publisher: Springer Science and Business Media LLC
Date: 09-2012
DOI: 10.1038/NATURE11405
Publisher: Springer Science and Business Media LLC
Date: 08-2018
DOI: 10.1016/J.PHAREP.2018.02.021
Abstract: Synaptic Ras-GTPase-activating protein 1 (SYNGAP1) is an abundant brain-specific protein localized at the postsynaptic density of mammalian excitatory synapses. SYNGAP1 functions as a crucial regulator of downstream intracellular signaling triggered by N-methyl-d-aspartate receptor activation. One of the most important signaling pathways regulated by SYNGAP1 is the Ras-Raf-MEK-ERK pathway. SYNGAP1 deficiency is associated with hyperphosphorylation of MEK and ERK kinases and with altered synaptic function in Syngap1 Using electrophysiological recordings of field responses in hippoc al slices, we examined if disturbances of synaptic physiology in the hippoc us of 7-8-month old Syngap1 We found that in hippoc al slices from vehicle-treated Syngap1 The differential sensitivity of basal synaptic transmission and LTP to MEK inhibition indicates that the effects of SYNGAP1 deficiency on these synaptic parameters are mediated by distinct pathways. Our findings also suggest that at least some physiological phenotypes of the germline Syngap1 mutation can be ameliorated by pharmacological treatment of adult animals.
Publisher: Oxford University Press (OUP)
Date: 10-11-2012
DOI: 10.1093/NAR/GKS1040
Publisher: Elsevier BV
Date: 02-2004
DOI: 10.1016/S0896-6273(04)00048-0
Abstract: To identify the molecular mechanisms underlying psychostimulant-elicited plasticity in the brain reward system, we undertook a phenotype-driven approach using genome-wide microarray profiling of striatal transcripts from three genetic and one pharmacological mouse models of psychostimulant or dopamine supersensitivity. A small set of co-affected genes was identified. One of these genes encoding the synaptic scaffolding protein PSD-95 is downregulated in the striatum of all three mutants and in chronically, but not acutely, cocaine-treated mice. At the synaptic level, enhanced long-term potentiation (LTP) of the frontocortico-accumbal glutamatergic synapses correlates with PSD-95 reduction in every case. Finally, targeted deletion of PSD-95 in an independent line of mice enhances LTP, augments the acute locomotor-stimulating effects of cocaine, but leads to no further behavioral plasticity in response to chronic cocaine. Our findings uncover a previously unappreciated role of PSD-95 in psychostimulant action and identify a molecular and cellular mechanism shared between drug-related plasticity and learning.
Publisher: Springer Science and Business Media LLC
Date: 11-1997
DOI: 10.1038/36849
Abstract: Members of the Ras subfamily of small guanine-nucleotide-binding proteins are essential for controlling normal and malignant cell proliferation as well as cell differentiation. The neuronal-specific guanine-nucleotide-exchange factor, Ras-GRF/CDC25Mm, induces Ras signalling in response to Ca2+ influx and activation of G-protein-coupled receptors in vitro, suggesting that it plays a role in neurotransmission and plasticity in vivo. Here we report that mice lacking Ras-GRF are impaired in the process of memory consolidation, as revealed by emotional conditioning tasks that require the function of the amygdala learning and short-term memory are intact. Electrophysiological measurements in the basolateral amygdala reveal that long-term plasticity is abnormal in mutant mice. In contrast, Ras-GRF mutants do not reveal major deficits in spatial learning tasks such as the Morris water maze, a test that requires hippoc al function. Consistent with apparently normal hippoc al functions, Ras-GRF mutants show normal NMDA (N-methyl-D-aspartate) receptor-dependent long-term potentiation in this structure. These results implicate Ras-GRF signalling via the Ras/MAP kinase pathway in synaptic events leading to formation of long-term memories.
Publisher: Elsevier BV
Date: 07-1992
DOI: 10.1016/0165-3806(92)90249-V
Abstract: The mas proto-oncogene encodes a protein with a predicted structure similar to members of the family of seven transmembrane domain spanning receptors. These receptors are thought to transduce extracellular signals to G-proteins. Angiotensin II and III have been reported to be the functional ligands for the mas oncogene-encoded receptor (Jackson et al., 1988). We show here using in situ hybridization histochemistry and RNase protection assays that mas mRNA is expressed in a subpopulation of neurons in both the adult and developing rat CNS. In the adult CNS, mas mRNA is most abundant in hippoc al pyramidal neurons and dentate granule cells mas transcripts are also present at low levels in the cortex and thalamus. mas is first expressed in the developing rat CNS at postnatal day 1 (P1). Even at this early stage in CNS development the pattern of mas expression is similar to that seen in the adult. Although at P1 most neurons of the dentate gyrus are not yet generated and cells of the hippoc al CA fields are undergoing migration and synaptogenesis (Bayer 1980 Altman and Bayer, 1990a, 1990b, 1990c), mas is specifically expressed in these cell populations. This extremely restricted pattern of expression suggests that mas may function in determining the morphology and connections of specific cell types in the hippoc us. This function may in part be carried out by the ability of mas to link external cues to intracellular processes.
Publisher: Springer Science and Business Media LLC
Date: 09-09-2009
DOI: 10.1038/NRN2717
Abstract: Understanding the evolutionary origins of behaviour is a central aim in the study of biology and may lead to insights into human disorders. Synaptic transmission is observed in a wide range of invertebrate and vertebrate organisms and underlies their behaviour. Proteomic studies of the molecular components of the highly complex mammalian postsynaptic machinery point to an ancestral molecular machinery in unicellular organisms--the protosynapse--that existed before the evolution of metazoans and neurons, and hence challenges existing views on the origins of the brain. The phylogeny of the molecular components of the synapse provides a new model for studying synapse ersity and complexity, and their implications for brain evolution.
Publisher: Elsevier BV
Date: 06-2011
Publisher: Wiley
Date: 10-10-2013
DOI: 10.1111/ADB.12087
Publisher: Springer Science and Business Media LLC
Date: 15-09-2006
DOI: 10.1007/S10519-006-9114-3
Abstract: The mammalian postsynaptic proteome (PSP) comprises a highly interconnected set of approximately 1,000 proteins. The PSP is organized into macromolecular complexes that have a modular architecture defined by protein interactions and function. Signals initiated by neurotransmitter receptors are integrated by these complexes and their constituent enzymes to orchestrate multiple downstream cellular changes, including transcriptional regulation of genes at the nucleus. Genome wide transcriptome studies are beginning to map the sets of genes regulated by the synapse proteome. Conversely, understanding the transcriptional regulation of genes encoding the synapse proteome will shed light on synapse formation. Mutations that disrupt synapse signalling complexes result in cognitive impairments in mice and humans, and recent evidence indicates that these mutation change gene expression profiles. We discuss the need for global approaches combining genetics, transcriptomics and proteomics in order to understand cognitive function and disruption in diseases.
Publisher: Wiley
Date: 20-07-2015
DOI: 10.1111/EVA.12286
Publisher: EMBO
Date: 11-01-2017
Abstract: Exposure to cocaine generates silent synapses in the nucleus accumbens ( NA c), whose eventual unsilencing/maturation by recruitment of calcium‐permeable AMPA ‐type glutamate receptors ( CP ‐ AMPAR s) after drug withdrawal results in profound remodeling of NA c neuro‐circuits. Silent synapse‐based NA c remodeling was shown to be critical for several drug‐induced behaviors, but its role in acquisition and retention of the association between drug rewarding effects and drug‐associated contexts has remained unclear. Here, we find that the postsynaptic proteins PSD ‐93, PSD ‐95, and SAP 102 differentially regulate excitatory synapse properties in the NA c. Mice deficient for either of these scaffold proteins exhibit distinct maturation patterns of silent synapses and thus provided instructive animal models to examine the role of NA c silent synapse maturation in cocaine‐conditioned place preference ( CPP ). Wild‐type and knockout mice alike all acquired cocaine‐ CPP and exhibited increased levels of silent synapses after drug‐context conditioning. However, the mice differed in CPP retention and CP ‐ AMPAR incorporation. Collectively, our results indicate that CP ‐ AMPAR ‐mediated maturation of silent synapses in the NA c is a signature of drug–context association, but this maturation is not required for establishing or retaining cocaine‐ CPP .
Publisher: Society for Neuroscience
Date: 05-2003
Publisher: Elsevier BV
Date: 05-2001
DOI: 10.1016/S0166-2236(00)01792-6
Abstract: The recent success of large-scale industrialized genomic sequencing opens new doors in studies of biological systems. In the current post-genomic era we must ask how to translate this DNA sequence information into an understanding of living cells, tissues and organisms. One of the major goals is to characterize protein function, biochemical pathways and networks. Achieving this aim is greatly advanced by application of new proteomic tools combined with database mining. Neuroscience in particular is poised to benefit from these approaches in light of its high complexity and cross-talk between different neurotransmitter receptors within the same synapse or across the synaptic cleft. Little is known about the global in vivo protein interactions within synapses, and the knowledge of all proteins present in such structures will help in determining sub-complexes and the modular arrangement of proteins within them. This article reviews the impact of and outlines the application of proteomic analysis in the field of neuroscience, illustrating this with the ex le of NMDA receptor complexes.
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.NLM.2013.06.006
Abstract: Human disorders of cognition arise from hundreds of gene mutations and mice serve as models for developing and testing therapeutic approaches. Recent advancements using touchscreen psychological tests that measure similar components of cognition in mice and humans can be combined with genetics. These experiments formally demonstrate that different components of cognition in humans and mice are not merely analogous, but homologous, sharing common descent and genetic constitution. They also show that it is possible to genetically dissect different behaviours and identify their underlying molecular mechanisms. Using these methods as standardised approaches offers the prospect of understanding the genetic architecture of the cognitive repertoire and the identification of new targets for drug development. Rigorously defining homologous mechanisms using genetics and touchscreen tests may also improve drug trial design. Recommendations for mouse clinical trial protocols combined with human genetics are proposed.
Publisher: Elsevier BV
Date: 2016
Publisher: American Association for the Advancement of Science (AAAS)
Date: 23-08-2005
Abstract: Reversible protein phosphorylation mediated by kinases, phosphatases, and regulatory molecules is an essential mechanism of signal transduction in living cells. Although phosphorylation is the most intensively studied of the several hundred known posttranslational modifications on proteins, until recently the rate of identification of phosphorylation sites has remained low. The use of tandem mass spectrometry has greatly accelerated the identification of phosphorylation sites, although progress was limited by difficulties in phosphoresidue enrichment techniques. We have improved upon existing immobilized metal-affinity chromatography (IMAC) techniques for capturing phosphopeptides, to selectively purify phosphoproteins from complex mixtures. Combinations of phosphoprotein and phosphopeptide enrichment were more effective than current single phosphopeptide purification approaches. We have also implemented iterative mass spectrometry-based scanning techniques to improve detection of phosphorylated peptides in these enriched s les. Here, we provide detailed instructions for implementing and validating these methods together with analysis by tandem mass spectrometry for the study of phosphorylation at the mammalian synapse. This strategy should be widely applicable to the characterization of protein phosphorylation in erse tissues, organelles, and in cell culture.
Publisher: Oxford University Press (OUP)
Date: 15-10-2005
DOI: 10.1093/HMG/DDI330
Abstract: Proteomic experiments have produced a draft profile of the overall molecular composition of the mammalian neuronal synapse. It appears that synapses have over 1000 protein components and the mapping of their interactions, organization and functions will lead to a global view of the role of synapses in physiology and disease. A major functional subcomponent of the synaptic machinery is a multiprotein complex of glutamate receptors and adhesion proteins with associated adaptor and signalling enzymes totally 185 proteins known as the N-methyl-d-aspartate receptor complex/MAGUK associated signalling complex (NRC/MASC). Here, we review the proteomic studies and functions of NRC/MASC and specifically report on the role of its component genes in human diseases. Using a systematic literature search protocol, we identified reports of mutations or polymorphisms in 47 genes associated with 183 disorders, of which 54 were nervous system disorders. A similar number of genes are important in mouse synaptic plasticity and behaviour, where the NRC/MASC acts as a signalling complex with multiple functions provided by its in idual protein components and their interactions. The in idual gene mutations suggest not only an important role for the NRC/MASC in human diseases but that these diseases may be functionally connected by their common link to the NRC/MASC. The NRC/MASC is a rich source of genetic variation and provides a platform for understanding relationships of disease phenotype amenable to systematic studies such as the Genes to Cognition research consortium (www.genes2cognition.org) that links human and mouse genetics with proteomic studies.
Publisher: Informa UK Limited
Date: 04-2010
DOI: 10.1586/EPR.09.109
Publisher: Wiley
Date: 17-10-2005
DOI: 10.1111/J.1471-4159.2005.03507.X
Abstract: Characterization of the composition of the postsynaptic proteome (PSP) provides a framework for understanding the overall organization and function of the synapse in normal and pathological conditions. We have identified 698 proteins from the postsynaptic terminal of mouse CNS synapses using a series of purification strategies and analysis by liquid chromatography tandem mass spectrometry and large-scale immunoblotting. Some 620 proteins were found in purified postsynaptic densities (PSDs), nine in AMPA-receptor immuno-purifications, 100 in isolates using an antibody against the NMDA receptor subunit NR1, and 170 by peptide-affinity purification of complexes with the C-terminus of NR2B. Together, the NR1 and NR2B complexes contain 186 proteins, collectively referred to as membrane-associated guanylate kinase-associated signalling complexes. We extracted data from six other synapse proteome experiments and combined these with our data to provide a consensus on the composition of the PSP. In total, 1124 proteins are present in the PSP, of which 466 were validated by their detection in two or more studies, forming what we have designated the Consensus PSD. These synapse proteome data sets offer a basis for future research in synaptic biology and will provide useful information in brain disease and mental disorder studies.
Publisher: Springer Science and Business Media LLC
Date: 07-1970
DOI: 10.1038/76615
Abstract: N-methyl-d-aspartate receptors (NMDAR) mediate long-lasting changes in synapse strength via downstream signaling pathways. We report proteomic characterization with mass spectrometry and immunoblotting of NMDAR multiprotein complexes (NRC) isolated from mouse brain. The NRC comprised 77 proteins organized into receptor, adaptor, signaling, cytoskeletal and novel proteins, of which 30 are implicated from binding studies and another 19 participate in NMDAR signaling. NMDAR and metabotropic glutamate receptor subtypes were linked to cadherins and L1 cell-adhesion molecules in complexes lacking AMPA receptors. These neurotransmitter-adhesion receptor complexes were bound to kinases, phosphatases, GTPase-activating proteins and Ras with effectors including MAPK pathway components. Several proteins were encoded by activity-dependent genes. Genetic or pharmacological interference with 15 NRC proteins impairs learning and with 22 proteins alters synaptic plasticity in rodents. Mutations in three human genes (NF1, Rsk-2, L1) are associated with learning impairments, indicating the NRC also participates in human cognition.
Publisher: Oxford University Press (OUP)
Date: 2009
DOI: 10.1093/NAR/GKN700
Publisher: Springer Science and Business Media LLC
Date: 27-04-2004
DOI: 10.1038/NN1240
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.BIOPSYCH.2009.07.027
Abstract: Schizophrenia is a major psychiatric disease with strong evidence of genetic risk factors. Recent studies based on genome-wide study of copy number variations (CNVs) have detected novel recurrent submicroscopic copy number changes, including recurrent deletions at 1q21.11, 15q11.3, 15q13.3, and the recurrent CNV at the 2p16.3 neurexin 1 locus. These schizophrenia susceptibility CNV loci demonstrate that schizophrenia is, at least in part, genetic in origin and provide the basis for further investigation of mutations associated with the disease. The studies combined have also established the role of rare and-in sporadic cases-de novo variants in schizophrenia. Furthermore, neuronal-related genes and genetic pathways are starting to emerge from the CNV loci associated with schizophrenia. Here, we review the major findings in the recent literature, which begin to unravel the genetic and biological architecture of this complex human neuropsychiatric disorder.
Publisher: Frontiers Media SA
Date: 2012
Publisher: Springer Science and Business Media LLC
Date: 09-2009
DOI: 10.1038/NRN2701
Abstract: Advances in technology have equipped the field of neuroproteomics with refined tools for the study of the expression, interaction and function of proteins in the nervous system. In combination with bioinformatics, neuroproteomics can address the organization of dynamic, functional protein networks and macromolecular structures that underlie physiological, anatomical and behavioural processes. Furthermore, neuroproteomics is contributing to the elucidation of disease mechanisms and is a powerful tool for the identification of biomarkers.
Publisher: Elsevier BV
Date: 05-2012
Publisher: American Physical Society (APS)
Date: 24-08-2007
Publisher: Elsevier BV
Date: 04-1993
DOI: 10.1016/0197-0186(93)90019-2
Abstract: The study of ubiquitously expressed proto-oncogenes or tumor suppressor genes provided important insights into the second messenger signaling pathways common to neural and non-neural tissues. Therefore, it is expected that the analysis of proto-oncogenes expressed in neural tissues should probe into neurotrophic and neurotransmitter receptors, ion channels and other molecules involved in processes underlying basic physiological functions of the nervous system. This expectation is fulfilled by le experimental evidence. Using the trk, abl and src families of tyrosine kinase encoded proto-oncogenes, we discuss here new insights into the structural and functional organization of neural tissues gained from the molecular and genetic analyses of these genes and their products. Special attention is given to the description of initial steps of signaling through the Trk receptors in response to neurotrophic factors of the Nerve Growth Factor family. The genetic analysis of the Drosophila abl gene product identified new gene products that interact with the Abl protein. This analysis illuminates the power of Drosophila genetics in dissecting components of a signal transduction pathway. The Src-family of non-receptor type protein-tyrosine kinases is discussed from the point of functional redundancy as revealed by targeted gene disruption and expression studies. The recent progress in the field of proto-oncogenes has been impressive and it is expected that proto-oncogenes will continue to provide valuable tools in the study of the complex signaling pathways that underlie the physiological functions of the central nervous system.
Publisher: Springer Science and Business Media LLC
Date: 19-03-2022
DOI: 10.1007/S00401-022-02412-9
Abstract: Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder. Separate lines of evidence suggest that synapses and astrocytes play a role in the pathological mechanisms underlying ALS. Given that astrocytes make specialised contacts with some synapses, called tripartite synapses, we hypothesise that tripartite synapses could act as the fulcrum of disease in ALS. To test this hypothesis, we have performed an extensive microscopy-based investigation of synapses and tripartite synapses in the spinal cord of ALS model mice and post-mortem human tissue from ALS cases. We reveal widescale synaptic changes at the early symptomatic stages of the SOD1 G93a mouse model. Super-resolution microscopy reveals that large complex postsynaptic structures are lost in ALS mice. Most surprisingly, tripartite synapses are selectively lost, while non-tripartite synapses remain in equal number to healthy controls. Finally, we also observe a similar selective loss of tripartite synapses in human post-mortem ALS spinal cords. From these data we conclude that tripartite synaptopathy is a key hallmark of ALS.
Publisher: Cold Spring Harbor Laboratory
Date: 27-12-2021
DOI: 10.1101/2021.12.21.473638
Abstract: Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. Spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence occur in many disorders 1–10 , suggesting that brain circuits possess an intrinsic capacity to repair themselves. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6 , a neurodevelopmental disorder model 11 . Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the postnatal expansion of synapse ersity and acquisition of normal synaptome architecture were delayed in all brain regions, interfering with network and cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synaptome architecture to its normal developmental trajectory. Synapse subtypes with high rates of protein turnover mediated these events. These results show synaptome remodelling confers resilience to neurodevelopmental disorders.
Publisher: Elsevier BV
Date: 10-2006
DOI: 10.1016/J.NEURON.2006.09.012
Abstract: Trafficking of AMPA receptors (AMPA-Rs) to and from synapses controls the strength of excitatory synaptic transmission. However, proteins that cluster AMPA-Rs at synapses remain poorly understood. Here we show that PSD-95-like membrane-associated guanylate kinases (PSD-MAGUKs) mediate this synaptic targeting, and we uncover a remarkable functional redundancy within this protein family. By manipulating endogenous neuronal PSD-MAGUK levels, we find that both PSD-95 and PSD-93 independently mediate AMPA-R targeting at mature synapses. We also reveal unanticipated synapse heterogeneity as loss of either PSD-95 or PSD-93 silences largely nonoverlapping populations of excitatory synapses. In adult PSD-95 and PSD-93 double knockout animals, SAP-102 is upregulated and compensates for the loss of synaptic AMPA-Rs. At immature synapses, PSD-95 and PSD-93 play little role in synaptic AMPA-R clustering instead, SAP-102 dominates. These studies establish a PSD-MAGUK-specific regulation of AMPA-R synaptic expression that establishes and maintains glutamatergic synaptic transmission in the mammalian central nervous system.
Publisher: Springer Science and Business Media LLC
Date: 25-04-2016
DOI: 10.1038/SREP24626
Abstract: The molecular features of synapses in the hippoc us underpin current models of learning and cognition. Although synapse ultra-structural ersity has been described in the canonical hippoc al circuitry, our knowledge of sub-synaptic organisation of synaptic molecules remains largely unknown. To address this, mice were engineered to express Post Synaptic Density 95 protein (PSD95) fused to either eGFP or mEos2 and imaged with two orthogonal super-resolution methods: gated stimulated emission depletion (g-STED) microscopy and photoactivated localisation microscopy (PALM). Large-scale analysis of ~100,000 synapses in 7 hippoc al sub-regions revealed they comprised discrete PSD95 nanoclusters that were spatially organised into single and multi-nanocluster PSDs. Synapses in different sub-regions, cell-types and locations along the dendritic tree of CA1 pyramidal neurons, showed ersity characterised by the number of nanoclusters per synapse. Multi-nanocluster synapses were frequently found in the CA3 and dentate gyrus sub-regions, corresponding to large thorny excrescence synapses. Although the structure of in idual nanoclusters remained relatively conserved across all sub-regions, PSD95 packing into nanoclusters also varied between sub-regions determined from nanocluster fluorescence intensity. These data identify PSD95 nanoclusters as a basic structural unit, or building block, of excitatory synapses and their number characterizes synapse size and structural ersity.
Publisher: Springer Science and Business Media LLC
Date: 20-03-2019
DOI: 10.1038/S41467-019-09337-0
Abstract: Dendritic spines are the postsynaptic sites that receive most of the excitatory synaptic inputs, and thus provide the structural basis for synaptic function. Here, we describe an accurate method for measurement and analysis of spine morphology based on structured illumination microscopy (SIM) and computational geometry in cultured neurons. Surface mesh data converted from SIM images were comparable to data reconstructed from electron microscopic images. Dimensional reduction and machine learning applied to large data sets enabled identification of spine phenotypes caused by genetic mutations in key signal transduction molecules. This method, combined with time-lapse live imaging and glutamate uncaging, could detect plasticity-related changes in spine head curvature. The results suggested that the concave surfaces of spines are important for the long-term structural stabilization of spines by synaptic adhesion molecules.
Publisher: eLife Sciences Publications, Ltd
Date: 07-2017
Publisher: Springer Science and Business Media LLC
Date: 19-12-2010
DOI: 10.1038/NN.2719
Publisher: Public Library of Science (PLoS)
Date: 29-04-2011
Publisher: Elsevier BV
Date: 10-2017
Publisher: Wiley
Date: 29-12-2020
DOI: 10.1111/GBB.12723
Publisher: eLife Sciences Publications, Ltd
Date: 08-10-2014
DOI: 10.7554/ELIFE.03842
Abstract: Planar cell polarity (PCP) regulates basal body (BB) docking and positioning during cilia formation, but the underlying mechanisms remain elusive. In this study, we investigate the uncharacterized gene Flattop (Fltp) that is transcriptionally activated during PCP acquisition in ciliated tissues. Fltp knock-out mice show BB docking and ciliogenesis defects in multiciliated lung cells. Furthermore, Fltp is necessary for kinocilium positioning in monociliated inner ear hair cells. In these cells, the core PCP molecule Dishevelled 2, the BB/spindle positioning protein Dlg3, and Fltp localize directly adjacent to the apical plasma membrane, physically interact and surround the BB at the interface of the microtubule and actin cytoskeleton. Dlg3 and Fltp knock-outs suggest that both cooperatively translate PCP cues for BB positioning in the inner ear. Taken together, the identification of novel BB/spindle positioning components as potential mediators of PCP signaling might have broader implications for other cell types, ciliary disease, and asymmetric cell ision.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-12-1992
Abstract: Mice with mutations in four nonreceptor tyrosine kinase genes, fyn, src, yes, and abl, were used to study the role of these kinases in long-term potentiation (LTP) and in the relation of LTP to spatial learning and memory. All four kinases were expressed in the hippoc us. Mutations in src, yes, and abl did not interfere with either the induction or the maintenance of LTP. However, in fyn mutants, LTP was blunted even though synaptic transmission and two short-term forms of synaptic plasticity, paired-pulse facilitation and post-tetanic potentiation, were normal. In parallel with the blunting of LTP, fyn mutants showed impaired spatial learning, consistent with a functional link between LTP and learning. Although fyn is expressed at mature synapses, its lack of expression during development resulted in an increased number of granule cells in the dentate gyrus and of pyramidal cells in the CA3 region. Thus, a common tyrosine kinase pathway may regulate the growth of neurons in the developing hippoc us and the strength of synaptic plasticity in the mature hippoc us.
Publisher: Kluwer Academic Publishers
Date: 2004
Publisher: Cold Spring Harbor Laboratory
Date: 08-1995
Abstract: Signaling by tyrosine kinases is required for the induction of synaptic plasticity in the central nervous system. Comparison of fyn, src, yes, and abl nonreceptor tyrosine kinase mutant mice shows a specific requirement for Fyn in the induction of long-term potentiation at CA1 synapses in the hippoc us. To identify components of a Fyn-dependent pathway that may be involved with hippoc us function we examined tyrosine-phosphorylated proteins in kinase mutant mice. We found that nine proteins were hypophosphorylated specifically in fyn mutants. One of the hypophosphorylated proteins was focal adhesion tyrosine kinase (FAK). FAK also showed reduced activity in immunocomplex kinase assays only in fyn mutants. FAK is expressed at very high levels in the brain but in contrast to non-neural cells, FAK was not restricted to focal adhesion contacts. FAK was found in axons, dendrites, and the intermediate filament cytoskeleton of astrocytes. Brain extracts from the mutants also show specific patterns of compensatory changes in the activity of the remaining Src family kinases. Tyrosine phosphorylation is a critical regulator of FAK, and impairments in FAK signal transduction in fyn mutants may contribute to the mutant neural phenotype.
Publisher: Oxford University Press (OUP)
Date: 23-02-2006
DOI: 10.1093/BFGP/ELL013
Abstract: Proteomic study of the synapse has generated an extensive list of molecular components, revealing one of the most complex functional systems currently known to cell biology. While fundamental to neural information processing, behaviour and disease, the molecular organisation of the synapse and its relation to higher-level function has yet to be clearly understood. Neurotransmitter receptor complexes, such as the N-methyl-D-aspartate receptor complex (NRC/MASC), are major components of the synaptic proteome. We have recently completed a detailed study of MASC, its functional organisation and involvement in behaviour and disease. This pointed to simple design principles underlying synaptic organisation. Drawing together the results of proteomic and analytical study, we sketch out a model for synaptic functional organisation.
Publisher: Rockefeller University Press
Date: 18-05-2009
Abstract: All but the smallest-diameter axons in the central nervous system are myelinated, but the signals that initiate myelination are unknown. Our prior work has shown that integrin signaling forms part of the cell–cell interactions that ensure only those oligodendrocytes contacting axons survive. Here, therefore, we have asked whether integrins regulate the interactions that lead to myelination. Using homologous recombination to insert a single-copy transgene into the hypoxanthine phosphoribosyl transferase (hprt) locus, we find that mice expressing a dominant-negative β1 integrin in myelinating oligodendrocytes require a larger axon diameter to initiate timely myelination. Mice with a conditional deletion of focal adhesion kinase (a signaling molecule activated by integrins) exhibit a similar phenotype. Conversely, transgenic mice expressing dominant-negative β3 integrin in oligodendrocytes display no myelination abnormalities. We conclude that β1 integrin plays a key role in the axoglial interactions that sense axon size and initiate myelination, such that loss of integrin signaling leads to a delay in myelination of small-diameter axons.
Publisher: Springer Science and Business Media LLC
Date: 11-05-2021
DOI: 10.1038/S41598-021-88945-7
Abstract: Genes encoding synaptic proteins are highly associated with neuronal disorders many of which show clinical co-morbidity. We integrated 58 published synaptic proteomic datasets that describe over 8000 proteins and combined them with direct protein–protein interactions and functional metadata to build a network resource that reveals the shared and unique protein components that underpin multiple disorders. All the data are provided in a flexible and accessible format to encourage custom use.
Publisher: Society for Neuroscience
Date: 24-12-2008
DOI: 10.1523/JNEUROSCI.3398-08.2008
Abstract: Clustering of Kv1 channels at the juxtaparanodal region (JXP) in myelinated axons depends on their association with the Caspr2/TAG-1 adhesion complex. The interaction between these channels and Caspr2 was suggested to depend on PDZ (PSD-95/Discs large/zona occludens-1) scaffolding proteins. Here, we show that at a subset of the JXP, PSD-93 colocalizes with Caspr2, K + channels and its related protein postsynaptic density protein-95 (PSD-95). The localization of PSD-93 and PSD-95 depends on the presence of Caspr2, as both scaffolding proteins failed to accumulate at the JXP in mice lacking either Caspr2 or TAG-1. In contrast, Caspr2 and K + channels still colocalized and associated in PSD-93 , PSD-95 or double PSD-93/PSD-95 null mice. To directly evaluate the role of PDZ domain proteins in the function of Caspr2, we examined the ability of transgenic Caspr2 molecules lacking either their cytoplasmic domain (Caspr2dCT), or their PDZ-binding sequence (Caspr2dPDZ), to restore Kv1 channel clustering in Caspr2 null mice. We found that while Kv1 channels were distributed throughout internodes in nerves expressing Caspr2dCT, they were clustered at the JXP in axons expressing a full-length Caspr2 (Caspr2FL) or the Caspr2dPDZ transgene. Further proteomic analysis revealed that Caspr2 interacts with a distinct set of scaffolding proteins through its PDZ- and protein 4.1-binding sequences. These results demonstrate that while the molecular assembly of the JXP requires the cytoplasmic domain of Caspr2, its carboxy-terminal PDZ-binding motif is dispensable for Kv1 channel clustering. This mechanism is clearly distinct from the one operating at the axon initial segment, which requires PSD-93 for Kv1 channel clustering.
Publisher: American Society for Microbiology
Date: 15-09-2015
DOI: 10.1128/AEM.01239-15
Abstract: Bacterial endosymbionts have been identified as potentially useful biological control agents for a range of invertebrate vectors of disease. Previous studies of Culicoides (Diptera: Ceratopogonidae) species using conventional PCR assays have provided evidence of Wolbachia (1/33) and Cardinium (8/33) infections. Here, we screened 20 species of Culicoides for Wolbachia and Cardinium , utilizing a combination of conventional PCR and more sensitive quantitative PCR (qPCR) assays. Low levels of Cardinium DNA were detected in females of all but one of the Culicoides species screened, and low levels of Wolbachia were detected in females of 9 of the 20 Culicoides species. Sequence analysis based on partial 16S rRNA gene and gyrB sequences identified “ Candidatus Cardinium hertigii” from group C, which has previously been identified in Culicoides from Japan, Israel, and the United Kingdom. Wolbachia strains detected in this study showed 98 to 99% sequence identity to Wolbachia previously detected from Culicoides based on the 16S rRNA gene, whereas a strain with a novel wsp sequence was identified in Culicoides narrabeenensis. Cardinium isolates grouped to geographical regions independent of the host Culicoides species, suggesting possible geographical barriers to Cardinium movement. Screening also identified Asaia bacteria in Culicoides . These findings point to a ersity of low-level endosymbiont infections in Culicoides , providing candidates for further characterization and highlighting the widespread occurrence of these endosymbionts in this insect group.
Publisher: eLife Sciences Publications, Ltd
Date: 21-10-2016
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.BRAINRES.2006.03.075
Abstract: Post synaptic density protein 95 (PSD-95) is a postsynaptic adaptor protein coupling the NMDA receptor to downstream signalling pathways underlying plasticity. Mice carrying a targeted gene mutation of PSD-95 show altered behavioural plasticity including spatial learning, neuropathic pain, orientation preference in visual cortical cells, and cocaine sensitisation. These behavioural effects are accompanied by changes in long-term potentiation of synaptic transmission. In vitro studies of PSD-95 signalling indicate that it may play a role in regulating dendritic spine structure. Here, we show that PSD-95 mutant mice have alterations in dendritic spine density in the striatum (a 15% decrease along the dendritic length) and in the hippoc us (a localised 40% increase) without changes in dendritic branch patterns or gross neuronal architecture. These changes in spine density were accompanied by altered expression of proteins known to interact with PSD-95, including NR2B and SAP102, suggesting that PSD-95 plays a role in regulating the expression and activation of proteins found within the NMDA receptor complex. Thus, PSD-95 is an important regulator of neuronal structure as well as plasticity in vivo.
Publisher: Oxford University Press
Date: 12-2017
DOI: 10.1093/MED/9780190681425.003.0017
Abstract: Synapses are the hallmark of the neuroanatomy of the brain. The million billion synapses of the human brain connect the nerve cells into the networks that underpin all behavior. The molecular anatomy of synapses is also remarkably complicated with ~2000 proteins in the synapse proteome. The proteins are physically organized into a hierarchy of molecular machines that control synapse biology. These proteins integrate and compute the information in patterns of nerve cell activity. Mutations in hundreds of genes that encode synaptic proteins contribute to over one hundred brain diseases, including common mental disorders. The synapse proteome is of fundamental importance to mental illness.
Publisher: Portland Press Ltd.
Date: 22-03-2010
DOI: 10.1042/BST0380445
Abstract: Understanding how cognitive processes including learning, memory, decision making and ideation are encoded by the genome is a key question in biology. Identification of sets of genes underlying human mental disorders is a path towards this objective. Schizophrenia is a common disease with cognitive symptoms, high heritability and complex genetics. We have identified genes involved with schizophrenia by measuring differences in DNA copy number across the entire genome in 91 schizophrenia cases and 92 controls in the Scottish population. Our data reproduce rare and common variants observed in public domain data from & schizophrenia cases, confirming known disease loci as well as identifying novel loci. We found copy number variants in PDE10A (phosphodiesterase 10A), CYFIP1 [cytoplasmic FMR1 (Fragile X mental retardation 1)-interacting protein 1], K+ channel genes KCNE1 and KCNE2, the Down's syndrome critical region 1 gene RCAN1 (regulator of calcineurin 1), cell-recognition protein CHL1 (cell adhesion molecule with homology with L1CAM), the transcription factor SP4 (specificity protein 4) and histone deacetylase HDAC9, among others (see www.genes2cognition.org/SCZ-CNV). Integrating the function of these many genes into a coherent model of schizophrenia and cognition is a major unanswered challenge.
Publisher: eLife Sciences Publications, Ltd
Date: 09-2023
DOI: 10.7554/ELIFE.89376
Publisher: Springer Science and Business Media LLC
Date: 15-01-2008
Abstract: Glutamate gated postsynaptic receptors in the central nervous system (CNS) are essential for environmentally stimulated behaviours including learning and memory in both invertebrates and vertebrates. Though their genetics, biochemistry, physiology, and role in behaviour have been intensely studied in vitro and in vivo , their molecular evolution and structural aspects remain poorly understood. To understand how these receptors have evolved different physiological requirements we have investigated the molecular evolution of glutamate gated receptors and ion channels, in particular the N -methyl- D -aspartate (NMDA) receptor, which is essential for higher cognitive function. Studies of rodent NMDA receptors show that the C-terminal intracellular domain forms a signalling complex with enzymes and scaffold proteins, which is important for neuronal and behavioural plasticity The vertebrate NMDA receptor was found to have subunits with C-terminal domains up to 500 amino acids longer than invertebrates. This extension was specific to the NR2 subunit and occurred before the duplication and subsequent ergence of NR2 in the vertebrate lineage. The shorter invertebrate C-terminus lacked vertebrate protein interaction motifs involved with forming a signaling complex although the terminal PDZ interaction domain was conserved. The vertebrate NR2 C-terminal domain was predicted to be intrinsically disordered but with a conserved secondary structure. We highlight an evolutionary adaptation specific to vertebrate NMDA receptor NR2 subunits. Using in silico methods we find that evolution has shaped the NMDA receptor C-terminus into an unstructured but modular intracellular domain that parallels the expansion in complexity of an NMDA receptor signalling complex in the vertebrate lineage. We propose the NR2 C-terminus has evolved to be a natively unstructured yet flexible hub organising postsynaptic signalling. The evolution of the NR2 C-terminus and its associated signalling complex may contribute to species differences in behaviour and in particular cognitive function.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Proceedings of the National Academy of Sciences
Date: 06-1990
Abstract: Plasmids comprising transgene insertions in four lines of transgenic mice have been retrieved by plasmid rescue into a set of Escherichia coli strains with mutations in different members of the methylation-dependent restriction system (MDRS). Statistical analysis of plasmid rescue frequencies has revealed that the MDRS loci detect differential modifications of the transgene insertions among mouse lines that show distinctive patterns of transgene expression. Plasmids in mice that express hybrid insulin transgenes during development can be readily cloned into E. coli strains carrying mutations in two of the MDRS loci, mcrA and mcrB. In mice in which transgene expression is inappropriately delayed into adulthood, plasmids can only be cloned into E. coli that carry mutations in all known MDRS activities. Differential cloning frequencies in the presence or absence of the various methylation-dependent restriction genes represent a further way to distinguish regions of mammalian chromosomes. These multiply deficient E. coli strains will also facilitate the molecular cloning of modified chromosomal DNA.
Publisher: Elsevier BV
Date: 06-2001
DOI: 10.1016/S0959-4388(00)00220-8
Abstract: Synaptic transmission of distinct patterns of spikes, or 'neural code', leads to plastic changes in synapses and other parts of the neuron, as well as learning in animals. Recent findings indicate that specialized multiprotein structures associated with neurotransmitter receptors and cell-adhesion proteins function as molecular devices that both read the neural code and initiate long-term changes in synaptic structure and function.
Publisher: Proceedings of the National Academy of Sciences
Date: 06-08-2018
Abstract: In vivo fluorescence microscopy with resolution well beyond the diffraction limit entails complexities that challenge the attainment of sufficient image brightness and contrast. These challenges have so far h ered investigations of the nanoscale distributions of synaptic proteins in the living mouse. Here, we describe a combination of stimulated emission depletion microscopy and endogenous protein labeling, providing high-quality in vivo data of the key scaffolding protein PSD95 at the postsynaptic membrane, which frequently appeared in extended distributions rather than as isolated nanoclusters. Operating in the far-red to near-IR wavelength range, this combination promises reduced photostress compared with prior in vivo nanoscopy at much shorter wavelengths.
Publisher: Frontiers Media SA
Date: 21-08-2023
DOI: 10.3389/FNMOL.2023.1027898
Abstract: Amyotrophic Lateral Sclerosis (ALS) is characterised by a loss of motor neurons in the brain and spinal cord that is preceded by early-stage changes in synapses that may be associated with TAR-DNA-Binding Protein 43 (TDP-43) pathology. Cellular inclusions of hyperphosphorylated TDP-43 (pTDP-43) are a key hallmark of neurodegenerative diseases such ALS. However, there has been little characterisation of the synaptic expression of TDP-43 inside subpopulations of spinal cord synapses. This study utilises a range of high-resolution and super-resolution microscopy techniques with immunolabelling, as well as an aptamer-based TDP-43 labelling strategy visualised with single-molecule localisation microscopy, to characterise and quantify the presence of pTDP-43 in populations of excitatory synapses near where motor neurons reside in the lateral ventral horn of the mouse lumbar spinal cord. We observe that TDP-43 is expressed in approximately half of spinal cord synapses as nanoscale clusters. Synaptic TDP-43 clusters are found most abundantly at synapses associated with VGLUT1-positive presynaptic terminals, compared to VGLUT2-associated synapses. Our nanoscopy techniques showed no difference in the subsynaptic expression of pTDP-43 in the ALS mouse model, SOD1 G93a , compared to healthy controls, despite prominent structural deficits in VGLUT1-associated synapses in SOD1 G93a mice. This research characterises the basic synaptic expression of TDP-43 with nanoscale precision and provides a framework with which to investigate the potential relationship between TDP-43 pathology and synaptic pathology in neurodegenerative diseases.
Publisher: Proceedings of the National Academy of Sciences
Date: 18-02-2003
Abstract: How in idual receptive field properties are formed in the maturing sensory neocortex remains largely unknown. The shortening of N -methyl- d -aspartate (NMDA) receptor currents by 2A subunit (NR2A) insertion has been proposed to delimit the critical period for experience-dependent refinement of circuits in visual cortex. In mice engineered to maintain prolonged NMDA responses by targeted deletion of NR2A, the sensitivity to monocular deprivation was surprisingly weakened but restricted to the typical critical period and delayed normally by dark rearing from birth. Orientation preference instead failed to mature, occluding further effects of dark rearing. Interestingly, a full ocular dominance plasticity (but not orientation bias) was selectively restored by enhanced inhibition, reflecting an imbalanced excitation in the absence of NR2A. Many of the downstream pathways involved in NMDA signaling are coupled to the receptor through a variety of protein–protein interactions and adaptor molecules. To further investigate a mechanistic dissociation of receptive field properties in the developing visual system, mice carrying a targeted disruption of the NR2A-associated 95-kDa postsynaptic density (PSD95) scaffolding protein were analyzed. Although the development and plasticity of ocular dominance was unaffected, orientation preference again failed to mature in these mice. Taken together, our results demonstrate that the cellular basis generating in idual sensory response properties is separable in the developing neocortex.
Publisher: Springer Science and Business Media LLC
Date: 08-06-2008
DOI: 10.1038/NN.2135
Publisher: Springer Science and Business Media LLC
Date: 12-06-2012
DOI: 10.1038/NCOMMS1900
Publisher: Wiley
Date: 1989
DOI: 10.1111/J.1399-3011.1989.TB00681.X
Abstract: The cDNA for a widely distributed neuroendocrine protein called 7B2 has been cloned from beta cell tumors of transgenic mice and sequenced. As deduced from the cDNA sequence, 7B2 is a secretory protein of 186 amino acids, nearly identical to its human and porcine homologs. The presence of several pairs of basic residues in the carboxyl terminal portion of the protein suggests that 7B2 can undergo proteolytic maturation in secretory granules and thus generate potential bioactive peptides. 7B2 mRNA is about 1.5 kilobase long and is apparently transcribed from a single gene per haploid genome. The use of tissue-specific promoters to express oncogenes in rare cell types of transgenic mice is a powerful tool for immortalization and expansion of these cells, and it facilitates the isolation and the study of rare proteins such as 7B2.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2014
DOI: 10.1038/TP.2013.114
Abstract: Differences in general cognitive ability (intelligence) account for approximately half of the variation in any large battery of cognitive tests and are predictive of important life events including health. Genome-wide analyses of common single-nucleotide polymorphisms indicate that they jointly tag between a quarter and a half of the variance in intelligence. However, no single polymorphism has been reliably associated with variation in intelligence. It remains possible that these many small effects might be aggregated in networks of functionally linked genes. Here, we tested a network of 1461 genes in the postsynaptic density and associated complexes for an enriched association with intelligence. These were ascertained in 3511 in iduals (the Cognitive Ageing Genetics in England and Scotland (CAGES) consortium) phenotyped for general cognitive ability, fluid cognitive ability, crystallised cognitive ability, memory and speed of processing. By analysing the results of a genome wide association study (GWAS) using Gene Set Enrichment Analysis, a significant enrichment was found for fluid cognitive ability for the proteins found in the complexes of N -methyl-D-aspartate receptor complex P =0.002. Replication was sought in two additional cohorts ( N =670 and 2062). A meta-analytic P -value of 0.003 was found when these were combined with the CAGES consortium. The results suggest that genetic variation in the macromolecular machines formed by membrane-associated guanylate kinase (MAGUK) scaffold proteins and their interaction partners contributes to variation in intelligence.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 1994
DOI: 10.1016/0166-2236(94)90077-9
Abstract: Novel transgenic approaches provide an exciting opportunity to assess the impact of the loss of specific genes in the biochemistry and electrophysiology of neurons involved in a learned behavior. Recent studies describing mice harboring mutations in five kinase genes expressed in the hippoc us found that two of these kinases, the alpha-Ca(2+)-calmodulin-dependent kinase II and the Fyn tyrosine kinase are necessary for the establishment of long-term potentiation. In addition to providing a new tool for the dissection of the molecular mechanisms of synaptic plasticity, these mutants will be important in determining how changes in synaptic strength affect not only learning and memory, but also a host of other processes thought to be associated with plasticity.
Publisher: Springer Science and Business Media LLC
Date: 08-09-2009
Abstract: Synapse formation and the development of neural networks are known to be controlled by a coordinated program of mRNA synthesis. microRNAs are now recognized to be important regulators of mRNA translation and stability in a wide variety of organisms. While specific microRNAs are known to be involved in neural development, the extent to which global microRNA and mRNA profiles are coordinately regulated in neural development is unknown. We examined mouse primary neuronal cultures, analyzing microRNA and mRNA expression. Three main developmental patterns of microRNA expression were observed: steady-state levels, up-regulated and down-regulated. Co-expressed microRNAs were found to have related target recognition sites and to be encoded in distinct genomic locations. A number of 43 differentially expressed miRNAs were located in five genomic clusters. Their predicted mRNA targets show reciprocal levels of expression. We identified a set of reciprocally expressed microRNAs that target mRNAs encoding postsynaptic density proteins and high-level steady-state microRNAs that target non-neuronal low-level expressed mRNAs. We characterized hundreds of miRNAs in neuronal culture development and identified three major modes of miRNA expression. We predict these miRNAs to regulate reciprocally expressed protein coding genes, including many genes involved in synaptogenesis. The identification of miRNAs that target mRNAs during synaptogenesis indicates a new level of regulation of the synapse.
Publisher: Frontiers Media SA
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 27-04-2016
DOI: 10.1038/NCOMMS11264
Abstract: How neuronal proteomes self-organize is poorly understood because of their inherent molecular and cellular complexity. Here, focusing on mammalian synapses we use blue-native PAGE and ‘gene-tagging’ of GluN1 to report the first biochemical purification of endogenous NMDA receptors (NMDARs) directly from adult mouse brain. We show that NMDARs partition between two discrete populations of receptor complexes and ∼1.5 MDa supercomplexes. We tested the assembly mechanism with six mouse mutants, which indicates a tripartite requirement of GluN2B, PSD93 and PSD95 gate the incorporation of receptors into ∼1.5 MDa supercomplexes, independent of either canonical PDZ-ligands or GluN2A. Supporting the essential role of GluN2B, quantitative gene-tagging revealed a fourfold molar excess of GluN2B over GluN2A in adult forebrain. NMDAR supercomplexes are assembled late in postnatal development and triggered by synapse maturation involving epigenetic and activity-dependent mechanisms. Finally, screening the quaternary organization of 60 native proteins identified numerous discrete supercomplexes that populate the mammalian synapse.
Publisher: Elsevier BV
Date: 11-2003
Publisher: Wiley
Date: 14-12-2023
Abstract: The multiple applications of super‐resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide‐guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non‐specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background‐free fluorescence microscopy. We have identified amine‐derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid‐phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal‐to‐background ratios. Furthermore, we have demonstrated their application in peptide‐PAINT imaging of postsynaptic density protein‐95 nanoclusters in the synaptosomes from mouse brain tissues.
Publisher: Cold Spring Harbor Laboratory
Date: 27-10-2020
DOI: 10.1101/2020.10.27.356899
Abstract: Synapses contain highly complex proteomes which control synaptic transmission, cognition and behaviour. Genes encoding synaptic proteins are associated with neuronal disorders many of which show clinical co-morbidity. Our hypothesis is that there is mechanistic overlap that is emergent from the network properties of the molecular complex. To test this requires a detailed and comprehensive molecular network model. We integrated 57 published synaptic proteomic datasets obtained between 2000 and 2019 that describe over 7000 proteins. The complexity of the postsynaptic proteome is reaching an asymptote with a core set of ~3000 proteins, with less data on the presynaptic terminal, where each new study reveals new components in its landscape. To complete the network, we added direct protein-protein interaction data and functional metadata including disease association. The resulting amalgamated molecular interaction network model is embedded into a SQLite database. The database is highly flexible allowing the widest range of queries to derive custom network models based on meta-data including species, disease association, synaptic compartment, brain region, and method of extraction. This network model enables us to perform in-depth analyses that dissect molecular pathways of multiple diseases revealing shared and unique protein components. We can clearly identify common and unique molecular profiles for co-morbid neurological disorders such as Schizophrenia and Bipolar Disorder and even disease comorbidities which span biological systems such as the intersection of Alzheimer’s Disease with Hypertension.
Publisher: Springer Science and Business Media LLC
Date: 20-02-2015
Publisher: Springer Science and Business Media LLC
Date: 28-10-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 09-12-1988
Abstract: Transgenic mouse lineages were established that carry the normal (M) or mutant (Z) alleles of the human alpha 1-antitrypsin (alpha 1-Pi) gene. All of the alpha 1-Pi transgenic mice expressed the human protein in the liver, cartilage, gut, kidneys, lymphoid macrophages, and thymus. The human M-allele protein was secreted normally into the serum. However, the human Z-allele protein accumulated in several cell types, but particularly in hepatocytes, and was found in serum in tenfold lower concentrations than the M-allele protein. Mice in one lineage carrying the mutant Z allele expressed high levels of human alpha 1-Pi RNA and displayed significant runting (50% of normal weight) in the neonatal period. This lineage was found to have alpha 1-Pi-induced liver pathology in the neonatal period, concomitant with the accumulation of human Z protein in diastase-resistant cytoplasmic globules that could be revealed in the Periodic acid-Schiff reaction (PAS). The phenotype of mice in the strain expressing high levels of the Z allele is remarkably similar to human neonatal hepatitis, and this strain may prove to be a useful animal model for studying this disease.
Publisher: Wiley
Date: 06-11-2019
DOI: 10.1111/EJN.14597
Publisher: Springer Science and Business Media LLC
Date: 10-01-2017
DOI: 10.1038/SREP40284
Abstract: Heterozygous mutations or deletions of the human Euchromatin Histone Methyltransferase 1 ( EHMT1 ) gene are the main causes of Kleefstra syndrome, a neurodevelopmental disorder that is characterized by impaired memory, autistic features and mostly severe intellectual disability. Previously, Ehmt1 +/− heterozygous knockout mice were found to exhibit cranial abnormalities and decreased sociability, phenotypes similar to those observed in Kleefstra syndrome patients. In addition, Ehmt1 +/− knockout mice were impaired at fear extinction and novel- and spatial object recognition. In this study, Ehmt1 +/− and wild-type mice were tested on several cognitive tests in a touchscreen-equipped operant chamber to further investigate the nature of learning and memory changes. Performance of Ehmt1 +/− mice in the Visual Discrimination & Reversal learning, object-location Paired-Associates learning- and Extinction learning tasks was found to be unimpaired. Remarkably, Ehmt1 +/− mice showed enhanced performance on the Location Discrimination test of pattern separation. In line with improved Location Discrimination ability, an increase in BrdU-labelled cells in the subgranular zone of the dentate gyrus was observed. In conclusion, reduced levels of EHMT1 protein in Ehmt1 +/− mice does not result in general learning deficits in a touchscreen-based battery, but leads to increased adult cell proliferation in the hippoc us and enhanced pattern separation ability.
Publisher: Springer Berlin Heidelberg
Date: 2003
Publisher: Wiley
Date: 10-2005
DOI: 10.1111/J.1460-9568.2005.04342.X
Abstract: The role of the endoplasmic reticulum (ER) localized in dendritic spines has become a subject of intense interest because of its potential functions in local protein synthesis and signal transduction. Although it is recognized from electron microscopic studies that not all spines contain ER, little is know of its dynamic regulation or turnover. Here, we report a surprising degree of turnover of ER within spines. Using confocal microscopy imaging we observed continuity of spine-ER with dendritic ER in hippoc al primary neurons. Over 24 h, less than 50% of spine ER was stable. Despite this high degree of turn over, we identified a significant subset of spines that maintained ER for at least 4 days. These results indicate that within a single neuron, the organelle composition of a spine is unexpectedly dynamic and may explain aspects of the spine-to-spine variation in calcium spike magnitude and localized protein synthesis and trafficking.
Publisher: Society for Neuroscience
Date: 16-06-2010
Publisher: Wiley
Date: 11-02-2011
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.NEURON.2010.06.026
Abstract: A large international consortium reports in Nature on the ersity of genomic changes in families with autism spectrum disorders. Inherited and de novo mutations affecting many genes were discovered implicating disruption to postsynaptic and cellular signaling processes.
Publisher: Elsevier BV
Date: 2016
Publisher: American Physiological Society
Date: 11-2018
Abstract: Although the activation of extrasynaptic GluN2B-containing N-methyl-d-aspartate (NMDA) receptors has been implicated in neurodegenerative diseases, such as Alzheimer’s and Huntington’s disease, their physiological function remains unknown. In this study, we found that extrasynaptic GluN2B receptors play a homeostatic role by antagonizing long-term potentiation (LTP) induction under conditions of prolonged synaptic stimulation. In particular, we have previously found that brief theta-pulse stimulation (5 Hz for 30 s) triggers robust LTP, whereas longer stimulation times (5 Hz for 3 min) have no effect on basal synaptic transmission in the hippoc al CA1 region. Here, we show that prolonged stimulation blocked LTP by activating extrasynaptic GluN2B receptors via glutamate spillover. In addition, we found that this homeostatic mechanism was absent in slices from the SAP102 knockout, providing evidence for a functional coupling between extrasynaptic GluN2B and the SAP102 scaffold protein. In conclusion, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction via the activation of extrasynaptic GluN2B-containing NMDA receptors. NEW & NOTEWORTHY Although long-term potentiation (LTP) is an attractive model for memory storage, it tends to destabilize neuronal circuits because it drives synapses toward a maximum value. Unless opposed by homeostatic mechanisms operating through negative feedback rules, cumulative LTP could render synapses unable to encode additional information. In this study, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction under conditions of prolonged synaptic stimulation via the activation of an extrasynaptic GluN2B-SAP102 complex.
Publisher: Elsevier BV
Date: 1996
DOI: 10.1016/S0928-4257(97)87914-4
Abstract: The NMDA receptor activates a biochemical pathway that regulates long-term changes in synaptic strength. A combination of pharmacological and gene-knockout approaches shows that the postsynaptics signalling cascade initiated by the NMDA receptor involves Fyn tyrosine kinase. We found that Fyn phosphorylates the NMDA receptor and proteins associated with the receptor and proteins associated with the receptor. The interaction of the NMDA receptor with postsynaptic signalling proteins is likely to initiate changes in synaptic strength that contribute to learning and memory.
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.NEURON.2006.08.024
Abstract: Arc/Arg3.1 is robustly induced by plasticity-producing stimulation and specifically targeted to stimulated synaptic areas. To investigate the role of Arc/Arg3.1 in synaptic plasticity and learning and memory, we generated Arc/Arg3.1 knockout mice. These animals fail to form long-lasting memories for implicit and explicit learning tasks, despite intact short-term memory. Moreover, they exhibit a biphasic alteration of hippoc al long-term potentiation in the dentate gyrus and area CA1 with an enhanced early and absent late phase. In addition, long-term depression is significantly impaired. Together, these results demonstrate a critical role for Arc/Arg3.1 in the consolidation of enduring synaptic plasticity and memory storage.
Publisher: Cold Spring Harbor Laboratory
Date: 23-11-2015
DOI: 10.1101/032680
Abstract: The cell types that trigger the primary pathology in many brain diseases remain largely unknown. One route to understanding the primary pathological cell type for a particular disease is to identify the cells expressing susceptibility genes. Although this is straightforward for monogenic conditions where the causative mutation may alter expression of a cell type specific marker, methods are required for the common polygenic disorders. We developed the Expression Weighted Cell Type Enrichment (EWCE) method that uses single cell transcriptomes to generate the probability distribution associated with a gene list having an average level of expression within a cell type. Following validation, we applied EWCE to human genetic data from cases of epilepsy, Schizophrenia, Autism, Intellectual Disability, Alzheimer’s disease, Multiple Sclerosis and anxiety disorders. Genetic susceptibility primarily affected microglia in Alzheimer’s and Multiple Sclerosis was shared between interneurons and pyramidal neurons in Autism and Schizophrenia while intellectual disabilities and epilepsy were attributable to a range of cell-types, with the strongest enrichment in interneurons. We hypothesized that the primary cell type pathology could trigger secondary changes in other cell types and these could be detected by applying EWCE to transcriptome data from diseased tissue. In Autism, Schizophrenia and Alzheimer’s disease we find evidence of pathological changes in all of the major brain cell types. These findings give novel insight into the cellular origins and progression in common brain disorders. The methods can be applied to any tissue and disorder and have applications in validating mouse models.
Publisher: Cold Spring Harbor Laboratory
Date: 2009
Abstract: Beneath the complexity of the human brain are molecular principles shaped by evolution explaining the origins of the behavioral repertoire. The role of the nervous system is to provide a repertoire of behaviors allowing the animal to respond and adapt to changing environments during the course of its life. Multiprotein complexes in the postsynaptic terminal of synapses control adaptive and cognitive processes in metazoan nervous systems. These multiprotein complexes are organized into molecular networks that detect and respond to patterns of neural activity. Combinations of proteins are used to build different complexes and pathways producing great ersity. These complexes evolved from an ancestral core set of proteins controlling adaptive behaviors in unicellular organisms known as the protosynapse. Later expansion in numbers and interactions resulted in more complex synapses in invertebrates and vertebrates. The resultant combinatorial complexity has contributed to the neuroanatomical, neurophysiological, and behavioral ersity in these species. Mutations in genes encoding the complexes result in many human diseases of the nervous system. This general mechanism of cognition provides a useful template for studying evolution of behavior in all animals.
Publisher: eLife Sciences Publications, Ltd
Date: 12-09-2017
DOI: 10.7554/ELIFE.17915
Abstract: The genetic mechanisms regulating the brain and behaviour across the lifespan are poorly understood. We found that lifespan transcriptome trajectories describe a calendar of gene regulatory events in the brain of humans and mice. Transcriptome trajectories defined a sequence of gene expression changes in neuronal, glial and endothelial cell-types, which enabled prediction of age from tissue s les. A major lifespan landmark was the peak change in trajectories occurring in humans at 26 years and in mice at 5 months of age. This species-conserved peak was delayed in females and marked a reorganization of expression of synaptic and schizophrenia-susceptibility genes. The lifespan calendar predicted the characteristic age of onset in young adults and sex differences in schizophrenia. We propose a genomic program generates a lifespan calendar of gene regulation that times age-dependent molecular organization of the brain and mutations that interrupt the program in young adults cause schizophrenia.
Publisher: American Chemical Society (ACS)
Date: 09-12-2021
Abstract: Optical imaging of protein aggregates in living and post-mortem tissue can often be impeded by unwanted fluorescence, prompting the need for novel methods to extract meaningful signal in complex biological environments. Historically, benzothiazolium derivatives, prominently Thioflavin T, have been the state-of-the-art fluorescent probes for amyloid aggregates, but their optical, structural, and binding properties typically limit them to
Publisher: Wiley
Date: 20-01-2017
DOI: 10.1111/GBB.12364
Abstract: Behavioural analysis of mice carrying engineered mutations is widely used to identify roles of specific genes in components of the mammalian behavioural repertoire. The reproducibility and robustness of phenotypic measures has become a concern that undermines the use of mouse genetic models for translational studies. Contributing factors include low in idual study power, non-standardized behavioural testing, failure to address confounds and differences in genetic background of mutant mice. We have examined the importance of these factors using a statistically robust approach applied to behavioural data obtained from three mouse mutations on 129S5 and C57BL/6J backgrounds generated in a standardized battery of five behavioural assays. The largest confounding effect was s ling variation, which partially masked the genetic background effect. Our observations suggest that strong interaction of mutation with genetic background in mice in innate and learned behaviours is not necessarily to be expected. We found composite measures of innate and learned behaviour were similarly impacted by mutations across backgrounds. We determined that, for frequently used group sizes, a single retest of a significant result conforming to the commonly used P < 0.05 threshold results in a reproducibility of 60% between identical experiments. Reproducibility was reduced in the presence of strain differences. We also identified a P-value threshold that maximized reproducibility of mutant phenotypes across strains. This study illustrates the value of standardized approaches for quantitative assessment of behavioural phenotypes and highlights approaches that may improve the translational value of mouse behavioural studies.
Publisher: Frontiers Media SA
Date: 02-10-2020
Publisher: Public Library of Science (PLoS)
Date: 12-12-2007
Publisher: Wiley
Date: 08-07-2015
DOI: 10.1111/GEB.12344
Publisher: MDPI AG
Date: 08-2018
Abstract: The proteome of the postsynaptic terminal of excitatory synapses comprises over one thousand proteins in vertebrate species and plays a central role in behavior and brain disease. The brain is organized into anatomically distinct regions and whether the synapse proteome differs across these regions is poorly understood. Postsynaptic proteomes were isolated from seven forebrain and hindbrain regions in mice and their composition determined using proteomic mass spectrometry. Seventy-four percent of proteins showed differential expression and each region displayed a unique compositional signature. These signatures correlated with the anatomical isions of the brain and their embryological origins. Biochemical pathways controlling plasticity and disease, protein interaction networks and in idual proteins involved with cognition all showed differential regional expression. Combining proteomic and connectomic data shows that interconnected regions have specific proteome signatures. Diversity in synapse proteome composition is key feature of mouse and human brain structure.
Publisher: Elsevier BV
Date: 08-1999
DOI: 10.1016/S0309-1740(99)00016-9
Abstract: Fifty buck kids from five goat genotypes, Boer × Angora (BA), Boer × Saanen (BS), Feral × Feral (FF), Saanen × Angora (SA) and Saanen × Feral (SF) were compared for production of Capretto and Chevon carcasses. BS and SF kids had significantly better average daily gain compared to other genotypes and took less time to reach the required liveweight for Capretto and Chevon production. The development of visceral organs was not influenced by genotype. Kids from dairy breeds (SA in case of Capretto and SF in case of the Chevon group) deposited more internal fat in comparison to other genotypes. Dressing percentage (based on empty body weight) of kids ranged from 50-55%. At the same liveweight, dressing percentage and eye muscle dimensions did not vary between genotypes. However, BS and SF kids produced longer carcasses. Subcutaneous fat thickness was significantly greater in Chevon carcasses from BA compared to other genotypes. A high correlation was found between fat thickness measured by ultrasound on the live animal and ruler measurement on the carcass at the 12/13th rib position. Based on growth and carcass characteristics BS and SF kids performed better than kids from other genotypes used in the present study.
Publisher: Society for Neuroscience
Date: 28-11-2007
DOI: 10.1523/JNEUROSCI.3056-07.2007
Abstract: Phosphorylation-dependent changes in AMPA receptor function have a crucial role in activity-dependent forms of synaptic plasticity such as long-term potentiation (LTP) and long-term depression (LTD). Although three previously identified phosphorylation sites in AMPA receptor glutamate receptor 1 (GluR1) subunits (S818, S831, and S845) appear to have important roles in LTP and LTD, little is known about the role of other putative phosphorylation sites in GluR1. Here, we describe the characterization of a recently identified phosphorylation site in GluR1 at threonine 840. The results of in vivo and in vitro phosphorylation assays suggest that T840 is not a substrate for protein kinases known to phosphorylate GluR1 at previously identified phosphorylation sites, such as protein kinase A, protein kinase C, and calcium/calmodulin-dependent kinase II. Instead, in vitro phosphorylation assays suggest that T840 is a substrate for p70S6 kinase. Although LTP-inducing patterns of synaptic stimulation had no effect on GluR1 phosphorylation at T840 in the hippoc al CA1 region, bath application of NMDA induced a strong, protein phosphatase 1- and/or 2A-mediated decrease in T840 phosphorylation. Moreover, GluR1 phosphorylation at T840 was transiently decreased by a chemical LTD induction protocol that induced a short-term depression of synaptic strength and persistently decreased by a chemical LTD induction protocol that induced a lasting depression of synaptic transmission. Together, our results show that GluR1 phosphorylation at T840 is regulated by NMDA receptor activation and suggest that decreases in GluR1 phosphorylation at T840 may have a role in LTD.
Publisher: Elsevier BV
Date: 02-2003
DOI: 10.1016/S0960-9822(03)00084-8
Abstract: Chronic pain due to nerve injury is resistant to current analgesics. Animal models of neuropathic pain show neuronal plasticity and behavioral reflex sensitization in the spinal cord that depend on the NMDA receptor. We reveal complexes of NMDA receptors with the multivalent adaptor protein PSD-95 in the dorsal horn of spinal cord and show that PSD-95 plays a key role in neuropathic reflex sensitization. Using mutant mice expressing a truncated form of the PSD-95 molecule, we show their failure to develop the NMDA receptor-dependent hyperalgesia and allodynia seen in the CCI model of neuropathic pain, but normal inflammatory nociceptive behavior following the injection of formalin. In wild-type mice following CCI, CaM kinase II inhibitors attenuate sensitization of behavioral reflexes, elevated constitutive (autophosphorylated) activity of CaM kinase II is detected in spinal cord, and increased amounts of phospho-Thr(286) CaM kinase II coimmunoprecipitate with NMDA receptor NR2A/B subunits. Each of these changes is prevented in PSD-95 mutant mice although CaM kinase II is present and can be activated. Disruption of CaM kinase II docking to the NMDA receptor and activation may be responsible for the lack of neuropathic behavioral reflex sensitization in PSD-95 mutant mice.
Publisher: Elsevier BV
Date: 10-2001
Publisher: Springer Science and Business Media LLC
Date: 04-12-2017
DOI: 10.1038/S41593-017-0025-9
Abstract: The postsynaptic proteome of excitatory synapses comprises ~1,000 highly conserved proteins that control the behavioral repertoire, and mutations disrupting their function cause >130 brain diseases. Here, we document the composition of postsynaptic proteomes in human neocortical regions and integrate it with genetic, functional and structural magnetic resonance imaging, positron emission tomography imaging, and behavioral data. Neocortical regions show signatures of expression of in idual proteins, protein complexes, biochemical and metabolic pathways. We characterized the compositional signatures in brain regions involved with language, emotion and memory functions. Integrating large-scale GWAS with regional proteome data identifies the same cortical region for smoking behavior as found with fMRI data. The neocortical postsynaptic proteome data resource can be used to link genetics to brain imaging and behavior, and to study the role of postsynaptic proteins in localization of brain functions.
Publisher: Cold Spring Harbor Laboratory
Date: 17-12-2021
DOI: 10.1101/2021.12.16.472938
Abstract: Protein turnover is required for synapse maintenance and remodelling and may impact memory duration. We quantified the lifetime of postsynaptic protein PSD95 in in idual excitatory synapses across the mouse brain and lifespan, generating the Protein Lifetime Synaptome Atlas. Excitatory synapses have a wide range of protein lifetimes that may extend from a few hours to several months, with distinct spatial distributions in dendrites, neuron types and brain regions. Short protein lifetime (SPL) synapses are enriched in developing animals and in regions controlling innate behaviors, whereas long protein lifetime (LPL) synapses accumulate during development, are enriched in the cortex and CA1 where memories are stored, and are preferentially preserved in old age. The protein lifetime synaptome architecture is disrupted in an autism model, with synapse protein lifetime increased throughout the brain. These findings add a further layer to synapse ersity in the brain and enrich prevailing concepts in behavior, development, ageing and brain repair.
Publisher: Wiley
Date: 2005
DOI: 10.1111/J.1460-9568.2005.03874.X
Abstract: Patterns of neural activity mediated by N-methyl-D-aspartate (NMDA) receptors are known to play important roles in development of the central nervous system. However, the signalling pathways downstream from NMDA receptors that are critical for normal neuronal development are not yet clearly understood. NMDA receptors interact with various signalling proteins via scaffolding proteins, which are important in adult neuronal and behavioural plasticity. For ex le, the NR2B subunits of the NMDA receptor interact with postsynaptic density 95 (PSD-95), which in turn binds to synaptic ras GTPase-activating protein (SynGAP). Interestingly, the developmental phenotype of mice carrying null mutations in these genes differ. NR2B and SynGAP homozygote mice die within the first week of birth whereas PSD-95 homozygote mice survive to adulthood. We therefore examined the expression patterns of PSD-95 and SynGAP genes from embryonic stages to adult using lacZ (beta-galactosidase) marker gene knock-in mice. Dramatic changes of expression were observed throughout development in brain and other tissues. Although SynGAP binds PSD-95, both genes had distinct, as well as overlapping expression. SynGAP expression peaked at times of synaptogenesis and developmental plasticity in contrast to PSD-95, which was expressed throughout the brain from early embryonic stages. Furthermore, SynGAP showed a more spatially restricted pattern as illustrated by its restriction to forebrain in contrast to PSD-95, which was also found in mid- and hindbrain. These data support the model that synaptic signalling complexes are heterogeneous and in idual components show temporal and spatial specificity during development.
Publisher: Elsevier BV
Date: 09-2021
DOI: 10.1016/J.NEUROPHARM.2021.108640
Abstract: Glutamate is the major excitatory neurotransmitter in vertebrate and invertebrate nervous systems. Proteins involved in glutamatergic neurotransmission, and chiefly glutamate receptors and their auxiliary subunits, play key roles in nervous system function. Thus, understanding their evolution and uncovering their ersity is essential to comprehend how nervous systems evolved, shaping cognitive function. Comprehensive phylogenetic analysis of these proteins across metazoans have revealed that their evolution is much more complex than what can be anticipated from vertebrate genomes. This is particularly true for ionotropic glutamate receptors (iGluRs), as their current classification into 6 classes (AMPA, Kainate, Delta, NMDA1, NMDA2 and NMDA3) would be largely incomplete. New work proposes a classification of iGluRs into 4 subfamilies that encompass 10 classes. Vertebrate AMPA, Kainate and Delta receptors would belong to one of these subfamilies, named AKDF, the NMDA subunits would constitute another subfamily and non-vertebrate iGluRs would be organised into the previously unreported Epsilon and Lambda subfamilies. Similarly, the animal evolution of metabotropic glutamate receptors has resulted in the formation of four classes of these receptors, instead of the three currently recognised. Here we review our current knowledge on the animal evolution of glutamate receptors and their auxiliary subunits. This article is part of the special issue on 'Glutamate Receptors - Orphan iGluRs'.
Publisher: Springer Science and Business Media LLC
Date: 02-02-2018
DOI: 10.1038/S41598-018-20610-Y
Abstract: The scaffold protein DLGAP1 is localized at the post-synaptic density (PSD) of glutamatergic neurons and is a component of supramolecular protein complexes organized by PSD95. Gain-of-function variants of DLGAP1 have been associated with obsessive-compulsive disorder (OCD), while haploinsufficient variants have been linked to autism spectrum disorder (ASD) and schizophrenia in human genetic studies. We tested male and female Dlgap1 wild type (WT), heterozygous (HT), and knockout (KO) mice in a battery of behavioral tests: open field, dig, splash, prepulse inhibition, forced swim, nest building, social approach, and sucrose preference. We also used biochemical approaches to examine the role of DLGAP1 in the organization of PSD protein complexes. Dlgap1 KO mice were most notable for disruption of protein interactions in the PSD, and deficits in sociability. Other behavioral measures were largely unaffected. Our data suggest that Dlgap1 knockout leads to PSD disruption and reduced sociability, consistent with reports of DLGAP1 haploinsufficient variants in schizophrenia and ASD.
Publisher: Elsevier BV
Date: 10-2003
DOI: 10.1016/J.CONB.2003.09.016
Abstract: Systems biology is a new branch of biology aimed at understanding biological complexity. Genomic and proteomic methods integrated with cellular and organismal analyses allow modelling of physiological processes. Progress in understanding synapse composition and new experimental and bioinformatics methods indicate the synapse is an excellent starting point for global systems biology of the brain. A neuroscience systems biology programme, organized as a consortium, is proposed.
Publisher: Springer Science and Business Media LLC
Date: 11-11-2022
DOI: 10.1038/S41467-022-34131-W
Abstract: Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. Nevertheless, spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence can occur in many disorders, suggesting that brain circuits possess an intrinsic capacity to overcome the deficits arising from some germline mutations. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6 , a neurodevelopmental disorder model. Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the molecular composition of excitatory synapses, the postnatal expansion of synapse ersity and the acquisition of normal synaptome architecture were delayed in all brain regions, interfering with networks and electrophysiological simulations of cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synapse ersity and synaptome architecture to the normal developmental trajectory. Synapse subtypes with rapid protein turnover mediated the synaptome remodeling. This brain-wide capacity for remodeling of synapse molecular composition to recover and maintain the developmental trajectory of synaptome architecture may help confer resilience to neurodevelopmental genetic disorders.
Publisher: Springer Science and Business Media LLC
Date: 18-05-2020
DOI: 10.1038/S41598-020-64874-9
Abstract: Functionally distinct synapses exhibit erse and complex organisation at molecular and nanoscale levels. Synaptic ersity may be dependent on developmental stage, anatomical locus and the neural circuit within which synapses reside. Furthermore, astrocytes, which align with pre and post-synaptic structures to form ‘tripartite synapses’, can modulate neural circuits and impact on synaptic organisation. In this study, we aimed to determine which factors impact the ersity of excitatory synapses throughout the lumbar spinal cord. We used PSD95-eGFP mice, to visualise excitatory postsynaptic densities (PSDs) using high-resolution and super-resolution microscopy. We reveal a detailed and quantitative map of the features of excitatory synapses in the lumbar spinal cord, detailing synaptic ersity that is dependent on developmental stage, anatomical region and whether associated with VGLUT1 or VGLUT2 terminals. We report that PSDs are nanostructurally distinct between spinal laminae and across age groups. PSDs receiving VGLUT1 inputs also show enhanced nanostructural complexity compared with those receiving VGLUT2 inputs, suggesting pathway-specific ersity. Finally, we show that PSDs exhibit greater nanostructural complexity when part of tripartite synapses, and we provide evidence that astrocytic activation enhances PSD95 expression. Taken together, these results provide novel insights into the regulation and ersification of synapses across functionally distinct spinal regions and advance our general understanding of the ‘rules’ governing synaptic nanostructural organisation.
Publisher: Cold Spring Harbor Laboratory
Date: 12-11-2019
DOI: 10.1101/838458
Abstract: How synapses change molecularly during the lifespan and across all brain circuits is unknown. We analyzed the protein composition of billions of in idual synapses from birth to old age on a brain-wide scale in the mouse, revealing a program of changes in the lifespan synaptome architecture spanning in idual dendrites to the systems level. Three major phases were uncovered, corresponding to human childhood, adulthood and old age. An arching trajectory of synaptome architecture drives the differentiation and specialization of brain regions to a peak in young adults before dedifferentiation returns the brain to a juvenile state. This trajectory underscores changing network organization and hippoc al physiology that may account for lifespan transitions in intellectual ability and memory, and the onset of behavioral disorders. The synaptome architecture of the mouse brain undergoes continuous changes that organize brain circuitry across the lifespan.
Publisher: Wiley
Date: 24-08-2006
Publisher: Proceedings of the National Academy of Sciences
Date: 23-12-1997
Abstract: We have isolated a novel cDNA, that appears to represent a new class of ion channels, by using the yeast two-hybrid system and the SH3 domain of the neural form of Src (N-src) as a bait. The encoded polypeptide, BCNG-1, is distantly related to cyclic nucleotide-gated channels and the voltage-gated channels, Eag and H-erg. BCNG-1 is expressed exclusively in the brain, as a glycosylated protein of ≈132 kDa. Immunohistochemical analysis indicates that BCNG-1 is preferentially expressed in specific subsets of neurons in the neocortex, hippoc us, and cerebellum, in particular pyramidal neurons and basket cells. Within in idual neurons, the BCNG-1 protein is localized to either the dendrites or the axon terminals depending on the cell type. Southern blot analysis shows that several other BCNG-related sequences are present in the mouse genome, indicating the emergence of an entire subfamily of ion channel coding genes. These findings suggest the existence of a new type of ion channel, which is potentially able to modulate membrane excitability in the brain and could respond to regulation by cyclic nucleotides.
Publisher: American Psychiatric Association Publishing
Date: 12-2010
Publisher: Annual Reviews
Date: 21-07-2012
DOI: 10.1146/ANNUREV-NEURO-062111-150433
Abstract: Proteomic studies of the composition of mammalian synapses have revealed a high degree of complexity. The postsynaptic and presynaptic terminals are molecular systems with highly organized protein networks producing emergent physiological and behavioral properties. The major classes of synapse proteins and their respective functions in intercellular communication and adaptive responses evolved in prokaryotes and eukaryotes prior to the origins of neurons in metazoa. In eukaryotes, the organization of in idual proteins into multiprotein complexes comprising scaffold proteins, receptors, and signaling enzymes formed the precursor to the core adaptive machinery of the metazoan postsynaptic terminal. Multiplicative increases in the complexity of this protosynapse machinery secondary to genome duplications drove synaptic, neuronal, and behavioral novelty in vertebrates. Natural selection has constrained ersification in mammalian postsynaptic mechanisms and the repertoire of adaptive and innate behaviors. The evolution and organization of synapse proteomes underlie the origins and complexity of nervous systems and behavior.
Publisher: Frontiers Media SA
Date: 27-01-2016
Publisher: Cold Spring Harbor Laboratory
Date: 19-12-2018
DOI: 10.1101/500447
Abstract: How is the information encoded within patterns of nerve impulses converted into erse behavioral responses? To address this question, we conducted the largest genetic study to date of the electrophysiological and behavioral properties of synapses. Postsynaptic responses to elementary patterns of activity in the hippoc al CA1 region were measured in 58 lines of mice carrying mutations in the principal classes of excitatory postsynaptic proteins. A combinatorial molecular mechanism was identified in which distinct subsets of proteins lified or attenuated responses across timescales from milliseconds to an hour. The same mechanism controlled the ersity and magnitude of innate and learned behavioral responses. PSD95 supercomplex proteins were central components of this synaptic machinery. The capacity of vertebrate synapses to compute activity patterns increased with genome evolution and is impaired by disease-relevant mutations. We propose that this species-conserved molecular mechanism converts the temporally encoded information in nerve impulses into the repertoire of innate and learned behavior.
Publisher: EMBO
Date: 2006
DOI: 10.1038/MSB4100041
Publisher: Wiley
Date: 07-01-2014
DOI: 10.1111/ADB.12110
Publisher: Cold Spring Harbor Laboratory
Date: 13-07-2018
DOI: 10.1101/368910
Abstract: The proteome of the postsynaptic terminal of excitatory synapses comprises over one thousand proteins in vertebrate species and plays a central role in behavior and brain disease. The brain is organized into anatomically distinct regions and whether the synapse proteome differs across these regions is poorly understood. Postsynaptic proteomes were isolated from seven forebrain and hindbrain regions in mice and their composition determined using proteomic mass spectrometry. Seventy-four percent of proteins showed differential expression and each region displayed a unique compositional signature. These signatures correlated with the anatomical isions of the brain and their embryological origins. Biochemical pathways controlling plasticity and disease, protein interaction networks and in idual proteins involved with cognition all showed differential regional expression. Combining proteomic and connectomic data shows that interconnected regions have specific proteome signatures. Diversity in synapse proteome composition is key feature of mouse and human brain structure.
Publisher: Wiley
Date: 07-08-2015
Publisher: Portland Press Ltd.
Date: 07-1986
DOI: 10.1042/CS0710117
Abstract: 1. Cigarette puffing parameters (puff volume, puff duration, number of puffs, total smoking time) and inhaled smoke volume (by a radiotracer techique) have been measured in a group of 11 asymptomatic smokers, once after topical anaesthesia of the upper airways and once without anaesthesia. 2. Topical anaesthesia significantly reduced the mean inhaled smoke volume per puff for the group from 41.1 ml to 30.6 ml (P & 0.05) and the total inhaled smoke volume from 575 ml to 528 ml (P = 0.05), but cigarette puffing parameters were unchanged. 3. It is concluded that stimulation of upper airway sensory receptors, probably sensitive to nicotine, may be an important mechanism in determining the amount of cigarette smoke inhaled by smokers.
Publisher: Cold Spring Harbor Laboratory
Date: 2018
DOI: 10.1101/SQB.2018.83.037887
Abstract: The purpose of this article is to outline a new molecular and synaptic theory of behavior called the "synaptomic theory," named because it is centered on the synaptome-the complement of synapses in the brain. Synaptomic theory posits that synapses are structures of high molecular complexity and vast ersity that are observable in maps of the brain and that these synaptome maps are fundamental to behavior. Synaptome maps are a means of writing or storing information that can be retrieved by the patterns of activity that stimulate synapses. Synaptome maps have the capacity to store large amounts of information, including multiple representations within the same map. The dynamic properties of synapses allow synaptome maps to store dynamic sequences of representations that could serve to program behavioral sequences. Synaptome maps are genetically programmed and experience-dependent, thereby storing innate and learned behaviors, respectively. Although learning occurs by modification of the synapse proteome, it does not require long-term potentiation (LTP) of synaptic weight or growth of new synapses, and the theory predicts that LTP modulates information recall. The spatial architecture of synaptome maps arise from an underlying molecular hierarchy linking the genome to the supramolecular assembly of proteins into complexes and supercomplexes. This molecular hierarchy can explain how genome evolution results in the behavioral repertoire of the organism. Mutations disrupting this molecular hierarchy change the architecture of synaptome maps, potentially accounting for the behavioral phenotypes associated with neurological and psychiatric disorders.
Publisher: Wiley
Date: 25-07-2017
DOI: 10.1111/JNC.14056
Publisher: Cold Spring Harbor Laboratory
Date: 15-12-2004
DOI: 10.1101/GAD.316304
Abstract: We have generated mice with a floxed fak allele under the control of keratin-14-driven Cre fused to a modified estrogen receptor ( Cre ER T2 ). 4-Hydroxy-tamoxifen treatment induced fak deletion in the epidermis, and suppressed chemically induced skin tumor formation. Loss of fak induced once benign tumors had formed inhibited malignant progression. Although fak deletion was associated with reduced migration of keratinocytes in vitro, we found no effect on wound re-epithelialization in vivo. However, increased keratinocyte cell death was observed after fak deletion in vitro and in vivo. Our work provides the first experimental proof implicating FAK in tumorigenesis, and this is associated with enhanced apoptosis.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.MICINF.2016.10.002
Abstract: The primary purpose of preoperative dental screening of medical patients is to detect acute or chronic oral conditions that may require management prior to planned medical interventions. The aim of this communication is to discuss the background of preoperative dental screening and the link between dental pathologies and systemic diseases.
Publisher: Public Library of Science (PLoS)
Date: 20-12-2006
Publisher: Frontiers Media SA
Date: 2009
Publisher: Society for Neuroscience
Date: 04-03-2009
DOI: 10.1523/JNEUROSCI.4424-08.2009
Abstract: Classical dopaminergic signaling paradigms and emerging studies on direct physical interactions between the D 1 dopamine (DA) receptor and the NMDA glutamate receptor predict a reciprocally facilitating, positive feedback loop. This loop, if not controlled, may cause concomitant overactivation of both D 1 and NMDA receptors, triggering neurotoxicity. Endogenous protective mechanisms must exist. Here, we report that PSD-95, a prototypical structural and signaling scaffold in the postsynaptic density, inhibits D 1 –NMDA receptor subunit 1 (NR1) NMDA receptor association and uncouples NMDA receptor-dependent enhancement of D 1 signaling. This uncoupling is achieved, at least in part, via a disinhibition mechanism by which PSD-95 abolishes NMDA receptor-dependent inhibition of D 1 internalization. Knockdown of PSD-95 immobilizes D 1 receptors on the cell surface and escalates NMDA receptor-dependent D 1 cAMP signaling in neurons. Thus, in addition to its role in receptor stabilization and synaptic plasticity, PSD-95 acts as a brake on the D 1 –NMDA receptor complex and d ens the interaction between them.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Cold Spring Harbor Laboratory
Date: 12-07-2022
DOI: 10.1101/2022.07.12.22277553
Abstract: Schizophrenia is a heritable psychiatric disorder with a polygenic architecture. Genome-wide association studies (GWAS) have reported an increasing number of risk-associated variants and polygenic risk scores (PRS) now explain 17% of the variance in the disorder. There exists substantial heterogeneity in the effect of these variants and aggregating them based on biologically relevant functions may provide mechanistic insight into the disorder. Using the largest schizophrenia GWAS to date, we calculated PRS based on 5 gene-sets previously found to contribute to the pathophysiology of schizophrenia: the postsynaptic density of excitatory synapses, postsynaptic membrane, dendritic spine, axon, and histone H3-K4 methylation gene-sets. We associated each PRS, along with respective whole-genome PRS (excluding single nucleotide polymorphisms in each gene-set), with neuroimaging (N ,000 cortical, subcortical, and white matter microstructure) and clinical (N ,000 psychotic-like experiences including conspiracies, communications, voices, visions, and distress) variables in healthy subjects in UK Biobank. A number of clinical and neuroimaging variables were significantly associated with the axon gene-set (psychotic-like communications: β=0.0916, p FDR =0.04, parahippoc al gyrus volume: β=0.0156, p FDR =0.03, FA thalamic radiations: β=-0.014, p FDR =0.036, FA posterior thalamic radiations: β=-0.016, p FDR =0.048), postsynaptic density gene-set (distress due to psychotic-like experiences: β=0.0588, p FDR =0.02, global surface area: β=-0.012, p FDR =0.034, and cingulate lobe surface area: β=-0.014, p FDR =0.04), and histone gene-set (entorhinal surface area: β=-0.016, p FDR =0.035). In the associations above, whole-genome PRS were significantly associated with psychotic-like communications (β=0.2218, p FDR =1.34×10 −7 ), distress (β=0.1943, p FDR =7.28×10 −16 ), and FA thalamic radiations (β=-0.0143, p FDR =0.036). Permutation analysis carried out for these associations revealed that they were not due to chance. Our results indicate that genetic variation in 3 gene-sets relevant to schizophrenia (axon, postsynaptic density, histone) may confer risk for the disorder through effects on a number of neuroimaging variables that have previously been implicated in schizophrenia. As neuroimaging associations were stronger for gene-set PRS than whole-genome PRS, findings here highlight that selection of biologically relevant variants may address the heterogeneity of the disorder by providing further mechanistic insight into schizophrenia.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-07-2020
Abstract: Excitatory synapses connect neurons in the brain to build the circuits that enable behavior. Cizeron et al. surveyed synapses in the mouse brain from birth to old age and present the data as a community resource, the Mouse Lifespan Synaptome Atlas (see the Perspective by Micheva et al. ). Molecular and morphological features defined 37 subtypes of synapses. Although synapse density generally increased in early development and declined in old age, the details differed in different brain areas. Science this issue p. 270 see also p. 253
Publisher: Elsevier BV
Date: 07-2008
Publisher: Oxford University Press (OUP)
Date: 27-07-2016
DOI: 10.1093/HMG/DDW244
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-10-2005
Publisher: Wiley
Date: 04-02-2014
Publisher: Cold Spring Harbor Laboratory
Date: 19-02-2020
DOI: 10.1101/2020.02.18.953802
Abstract: Determining the number of synapses that are present in different brain regions is crucial to understand brain connectivity as a whole. Membrane-associated guanylate kinases (MAGUKs) are a family of scaffolding proteins that are expressed in excitatory glutamatergic synapses. We used genetic labeling of two of these proteins (PSD95 and SAP102), and Spinning Disc confocal Microscopy (SDM), to estimate the number of fluorescent puncta in the CA1 area of the hippoc us. We also used FIB-SEM, a three-dimensional electron microscopy technique, to calculate the actual numbers of synapses in the same area. We then estimated the ratio between the three-dimensional densities obtained with FIB-SEM (synapses/μm 3 ) and the bi-dimensional densities obtained with SDM (puncta/100 μm 2 ). Given that it is impractical to use FIB-SEM brain-wide, we used previously available SDM data from other brain regions and we applied this ratio as a conversion factor to estimate the minimum density of synapses in those regions. We found the highest densities of synapses in the isocortex, olfactory areas, hippoc al formation and cortical subplate. Low densities were found in the pallidum, hypothalamus, brainstem and cerebellum. Finally, the striatum and thalamus showed a wide range of synapse densities.
Publisher: Springer Science and Business Media LLC
Date: 02-05-2015
Publisher: Proceedings of the National Academy of Sciences
Date: 13-03-2007
Abstract: Global biological datasets generated by genomics, transcriptomics, and proteomics provide new approaches to understanding the relationship between the genome and the synapse. Combined transcriptome analysis and multielectrode recordings of neuronal network activity were used in mouse embryonic primary neuronal cultures to examine synapse formation and activity-dependent gene regulation. Evidence for a coordinated gene expression program for assembly of synapses was observed in the expression of 642 genes encoding postsynaptic and plasticity proteins. This synaptogenesis gene expression program preceded protein expression of synapse markers and onset of spiking activity. Continued expression was followed by maturation of morphology and electrical neuronal networks, which was then followed by the expression of activity-dependent genes. Thus, two distinct sequentially active gene expression programs underlie the genomic programs of synapse function.
Publisher: Elsevier BV
Date: 2007
Publisher: Society for Neuroscience
Date: 11-2001
Publisher: Elsevier BV
Date: 09-2011
Publisher: Elsevier BV
Date: 10-1994
DOI: 10.1016/0959-4388(94)90010-8
Abstract: Gene targeting is revealing new molecular functions by creating very specific developmental, physiological and behavioral perturbations, and providing new insights into biochemical pathways underlying synaptic plasticity. Recent studies of mice carrying mutations in genes thought to be involved in modulating synaptic transmission have been subject to integrated biochemical, physiological and behavioral analyses.
Publisher: Public Library of Science (PLoS)
Date: 05-10-2012
Publisher: Springer Science and Business Media LLC
Date: 04-2002
DOI: 10.1038/NG0402-347
Publisher: Wiley
Date: 14-12-2023
Abstract: The multiple applications of super‐resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide‐guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non‐specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background‐free fluorescence microscopy. We have identified amine‐derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid‐phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal‐to‐background ratios. Furthermore, we have demonstrated their application in peptide‐PAINT imaging of postsynaptic density protein‐95 nanoclusters in the synaptosomes from mouse brain tissues.
Publisher: Elsevier BV
Date: 2008
Publisher: Elsevier BV
Date: 12-1991
DOI: 10.1016/0168-8227(91)90016-7
Abstract: We have shown that elevated plasma D-glucose levels in experimentally-induced diabetic nude athymic rats can be reduced by intraperitoneal transplantation of microcarrier-attached insulin producing beta cells from the mouse pancreatic beta cell line, beta TC-1. The reduction in the level of hyperglycemia was observed as early as two days following cell transplantation and was associated with a concomitant increase in plasma insulin levels. beta TC-1 cell transplanted diabetic rats had plasma D-glucose levels similar to those found in non-diabetic control animals and remained normoglycemic throughout the 39 day experimental period. The beta TC-1 cell transplanted diabetic rats also had near normalization of body weight, food and water intake and of urine output when compared to control diabetic and non-diabetic rats. Similarly, they exhibited improved blood glucose clearance following intravenous D-glucose administration. These results suggest that beta TC-1 cells regulate D-glucose homeostasis following transplantation into diabetic rat recipients in a manner similar to that of endogenous pancreatic beta cells.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1086/511441
Publisher: Springer US
Date: 2003
Publisher: eLife Sciences Publications, Ltd
Date: 21-07-2017
DOI: 10.7554/ELIFE.17161
Abstract: Aberrant NMDA receptor (NMDAR) activity contributes to several neurological disorders, but direct antagonism is poorly tolerated therapeutically. The GluN2B cytoplasmic C-terminal domain (CTD) represents an alternative therapeutic target since it potentiates excitotoxic signaling. The key GluN2B CTD-centred event in excitotoxicity is proposed to involve its phosphorylation at Ser-1303 by Dapk1, that is blocked by a neuroprotective cell-permeable peptide mimetic of the region. Contrary to this model, we find that excitotoxicity can proceed without increased Ser-1303 phosphorylation, and is unaffected by Dapk1 deficiency in vitro or following ischemia in vivo. Pharmacological analysis of the aforementioned neuroprotective peptide revealed that it acts in a sequence-independent manner as an open-channel NMDAR antagonist at or near the Mg2+ site, due to its high net positive charge. Thus, GluN2B-driven excitotoxic signaling can proceed independently of Dapk1 or altered Ser-1303 phosphorylation.
Publisher: Wiley
Date: 12-2003
DOI: 10.1002/BIES.10381
Abstract: All thoughts and actions are encoded in patterns of neuronal electrical activity. Circuits of nerve cells connected by synapses are dedicated to processing information in these patterns. Information is not only transmitted across the synapse but also monitored by postsynaptic molecular machines. These machines are macromolecular complexes of approximately 100 proteins organised into a network of protein interactions. The network can be mathematically described as a scale-free network. Components of the complexes are necessary for decoding the neural code and converting electrical information into biochemical changes. The network properties of these complexes may explain many of the features of neuronal plasticity and cognitive function in rodents. Importantly, these multiprotein complexes and their network properties shed new light on the basis of human cognitive diseases including schizophrenia, autism, Huntington's disease and mental retardation. Supplementary material for this article can be found on the BioEssays website pages/0265-9247/suppmat/index.html.
Publisher: Wiley
Date: 25-08-2006
Abstract: Modern high throughput technologies in biological science often create lists of interesting molecules. The challenge is to reconstruct a descriptive model from these lists that reflects the underlying biological processes as accurately as possible. Once we have such a model or network, what can we learn from it? Specifically, given that we are interested in some biological process associated with the model, what new properties can we predict and subsequently test? Here, we describe, at an introductory level, a range of bioinformatics techniques that can be systematically applied to proteomic datasets. When combined, these methods give us a global overview of the network and the properties of the proteins and their interactions. These properties can then be used to predict functional pathways within the network and to examine substructure. To illustrate the application of these methods, we draw upon our own work concerning a complex of 186 proteins found in neuronal synapses in mammals. The techniques discussed are generally applicable and could be used to examine lists of proteins involved with the biological response to electric or magnetic fields.
Publisher: Springer Science and Business Media LLC
Date: 21-12-2015
Publisher: Elsevier BV
Date: 12-1996
Abstract: Until recently, the mouse was rarely used to study the biology of learning and memory. With advancements in gene-targeting technology, which now allow the structure and expression of a specific protein to be controlled in the intact animal, the mouse provides a powerful new tool to explore cognitive function. In mice, in contrast to other organisms, it is now possible to regulate the expression of a protein in the same neurons that are electrophysiologically and biochemically manipulable and are in a circuit involved in a defined learned behavior. Mouse mutants have been described that alter synaptic physiology, neuroanatomy, neurochemistry, and behavior. The mutants provide the first opportunity to correlate these phenotypes within animals engineered with defined molecular alterations. This review will discuss a range of methodologies that are required to describe the phenotype of mice with synaptic and behavioral abnormalities and focus on the interpretative difficulties of integrating these techniques.
Publisher: Wiley
Date: 30-08-2012
Publisher: Wiley
Date: 25-06-2020
DOI: 10.1111/EJN.14846
Abstract: Mapping the molecular composition of in idual excitatory synapses across the mouse brain reveals high synapse ersity with each brain region showing a distinct composition of synapse types. As a first step towards systematic mapping of synapse ersity across the human brain, we have labelled and imaged synapses expressing the excitatory synapse protein PSD95 in twenty human brain regions, including 13 neocortical, two subcortical, one hippoc al, one cerebellar and three brainstem regions, in four phenotypically normal in iduals. We quantified the number, size and intensity of in idual synaptic puncta and compared their regional distributions. We found that each region showed a distinct signature of synaptic puncta parameters. Comparison of brain regions showed that cortical and hippoc al structures are similar, and distinct from those of cerebellum and brainstem. Comparison of synapse parameters from human and mouse brain revealed conservation of parameters, hierarchical organization of brain regions and network architecture. This work illustrates the feasibility of generating a systematic single‐synapse resolution atlas of the human brain, a potentially significant resource in studies of brain health and disease.
Publisher: Cold Spring Harbor Laboratory
Date: 19-07-2023
DOI: 10.1101/2023.07.19.549645
Abstract: How sleep deprivation affects cognition remains elusive. Synaptome mapping of excitatory synapses in 125 regions of the mouse brain revealed that sleep deprivation selectively reduces synapse ersity in the cortex and hippoc us. Sleep deprivation targeted specific types and subtypes of excitatory synapses while maintaining total synapse density. Altered synaptic responses to neural oscillations in a computational model suggest that sleep prevents cognitive impairments by maintaining normal brain synaptome architecture.
Publisher: Springer Science and Business Media LLC
Date: 19-09-2016
DOI: 10.1038/SREP33609
Abstract: Recent studies highlighted the importance of astrocyte-secreted molecules, such as ATP, for the slow modulation of synaptic transmission in central neurones. Biophysical mechanisms underlying the impact of gliotransmitters on the strength of in idual synapse remain, however, unclear. Here we show that purinergic P2X receptors can bring significant contribution to the signalling in the in idual synaptic boutons. ATP released from astrocytes facilitates a recruitment of P2X receptors into excitatory synapses by Ca 2+ -dependent mechanism. P2X receptors, co-localized with NMDA receptors in the excitatory synapses, can be activated by ATP co-released with glutamate from pre-synaptic terminals and by glia-derived ATP. An activation of P2X receptors in turn leads to down-regulation of postsynaptic NMDA receptors via Ca 2+ -dependent de-phosphorylation and interaction with PSD-95 multi-protein complex. Genetic deletion of the PSD-95 or P2X4 receptors obliterated ATP-mediated down-regulation of NMDA receptors. Impairment of purinergic modulation of NMDA receptors in the PSD-95 mutants dramatically decreased the threshold of LTP induction and increased the net magnitude of LTP. Our findings show that synergistic action of glia- and neurone-derived ATP can pre-modulate efficacy of excitatory synapses and thereby can have an important role in the glia-neuron communications and brain meta-plasticity.
Publisher: Oxford University Press (OUP)
Date: 09-1980
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.CONB.2012.02.002
Abstract: The human synapse proteome is a highly complex collection of proteins that is disrupted by hundreds of gene mutations causing over 100 brain diseases. These synaptic diseases, or synaptopathies, cause major psychiatric, neurological and childhood developmental disorders through mendelian and complex genetic mechanisms. The human postsynaptic proteome and its core signaling complexes built by the assembly of receptors and enzymes around Membrane Associated Guanylate Kinase (MAGUK) scaffold proteins are a paradigm for systematic analysis of synaptic diseases. In humans, the MAGUK Associated Signaling Complexes are mutated in Autism, Schizophrenia, Intellectual Disability and many other diseases, and mice carrying orthologous mutations show relevant cognitive, social, motoric and other phenotypes. Diseases with similar phenotypes and symptom spectrums arise from disruption of complexes and interacting proteins within the synapse proteome. Classifying synaptic disease phenotypes with genetic and proteome data provides a new brain disease classification system based on molecular etiology and pathogenesis.
Publisher: SAGE Publications
Date: 2008
Abstract: Glutamate receptors of the AMPA type (AMPArs) mediate fast excitatory transmission in the dorsal horn and are thought to underlie perception of both acute and chronic pain. They are tetrameric structures made up from 4 subunits (GluR1–4), and subunit composition determines properties of the receptor. Antigen retrieval with pepsin can be used to reveal the receptors with immunocytochemistry, and in this study we have investigated the subunit composition at synapses within laminae I–III of the dorsal horn. In addition, we have compared staining of AMPArs with that for PSD-95, a major constituent of glutamatergic synapses. We also examined tissue from knock-out mice to confirm the validity of the immunostaining. As we have shown previously, virtually all AMPAr-immunoreactive puncta were immunostained for GluR2. In laminae I–II, ~65% were GluR1-positive and ~60% were GluR3-positive, while in lamina III the corresponding values were 34% (GluR1) and 80% (GluR3). Puncta stained with antibody against the C-terminus of GluR4 (which only detects the long form of this subunit) made up 23% of the AMPAr-containing puncta in lamina I, ~8% of those in lamina II and 46% of those in lamina III. Some overlap between GluR1 and GluR3 was seen in each region, but in lamina I GluR1 and GluR4 were present in largely non-overlapping populations. The GluR4 puncta often appeared to outline dendrites of in idual neurons in the superficial laminae. Virtually all of the AMPAr-positive puncta were immunostained for PSD-95, and 98% of PSD-95 puncta contained AMPAr-immunoreactivity. Staining for GluR1, GluR2 and GluR3 was absent in sections from mice in which these subunits had been knocked out, while the punctate staining for PSD-95 was absent in mice with a mutation that prevents accumulation of PSD-95 at synapses. Our results suggest that virtually all glutamatergic synapses in laminae I–III of adult rat spinal cord contain AMPArs. They show that synapses in laminae I–II contain GluR2 together with GluR1 and/or GluR3, while the long form of GluR4 is restricted to specific neuronal populations, which may include some lamina I projection cells. They also provide further evidence that immunostaining for AMPAr subunits following antigen retrieval is a reliable method for detecting these receptors at glutamatergic synapses.
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.BRAINRESREV.2007.05.003
Abstract: 1906 was a landmark year in the history of the study of the nervous system, most notably for the first 'neuroscience' Nobel prize given to the anatomists Ramon Y Cajal and Camillo Golgi. 1906 is less well known for another event, also of great significance for neuroscience, namely the publication of Charles Sherrington's book 'The Integrative Action of the Nervous system'. It was Cajal and Golgi who debated the anatomical evidence for the synapse and it was Sherrington who laid its foundation in electrophysiological function. In tribute to these pioneers in synaptic biology, this article will address the issue of synapse ersity from the molecular point of view. In particular I will reflect upon efforts to obtain a complete molecular characterisation of the synapse and the unexpectedly high degree of molecular complexity found within it. A case will be made for developing approaches that can be used to generate a general catalogue of synapse types based on molecular markers, which should have wide application.
Publisher: Elsevier BV
Date: 1998
DOI: 10.1016/S0092-8674(00)80921-6
Abstract: NMDA receptors, a class of glutamate-gated cation channels with high Ca2+ conductance, mediate fast transmission and plasticity of central excitatory synapses. We show here that gene-targeted mice expressing NMDA receptors without the large intracellular C-terminal domain of any one of three NR2 subunits phenotypically resemble mice made deficient in that particular subunit. Mice expressing the NR2B subunit in a C-terminally truncated form (NR2B(deltaC/deltaC) mice) die perinatally. NR2A(deltaC/deltaC) mice are viable but exhibit impaired synaptic plasticity and contextual memory. These and NR2C(deltaC/deltaC) mice display deficits in motor coordination. C-terminal truncation of NR2 subunits does not interfere with the formation of gateable receptor channels that can be synaptically activated. Thus, the phenotypes of our mutants appear to reflect defective intracellular signaling.
Publisher: Elsevier
Date: 1999
Publisher: EMBO
Date: 14-05-2010
Publisher: Springer Science and Business Media LLC
Date: 12-1998
DOI: 10.1038/24790
Abstract: Specific patterns of neuronal firing induce changes in synaptic strength that may contribute to learning and memory. If the postsynaptic NMDA (N-methyl-D-aspartate) receptors are blocked, long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission and the learning of spatial information are prevented. The NMDA receptor can bind a protein known as postsynaptic density-95 (PSD-95), which may regulate the localization of and/or signalling by the receptor. In mutant mice lacking PSD-95, the frequency function of NMDA-dependent LTP and LTD is shifted to produce strikingly enhanced LTP at different frequencies of synaptic stimulation. In keeping with neural-network models that incorporate bidirectional learning rules, this frequency shift is accompanied by severely impaired spatial learning. Synaptic NMDA-receptor currents, subunit expression, localization and synaptic morphology are all unaffected in the mutant mice. PSD-95 thus appears to be important in coupling the NMDA receptor to pathways that control bidirectional synaptic plasticity and learning.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-04-2009
DOI: 10.1126/SCISIGNAL.2000102
Abstract: Analysis of protein phosphorylation patterns provides insight into the organization of molecular networks at the postsynaptic density.
Publisher: Frontiers Media SA
Date: 2011
Publisher: Oxford University Press (OUP)
Date: 13-11-2020
Abstract: Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is a risk factor for dementia later in life. Research into the pathophysiology of TBI has focused on the impact of injury on the neuron. However, recent advances have shown that TBI has a major impact on synapse structure and function through a combination of the immediate mechanical insult and the ensuing secondary injury processes, leading to synapse loss. In this review, we highlight the role of the synapse in TBI pathophysiology with a focus on the confluence of multiple secondary injury processes including excitotoxicity, inflammation and oxidative stress. The primary insult triggers a cascade of events in each of these secondary processes and we discuss the complex interplay that occurs at the synapse. We also examine how the synapse is impacted by traumatic axonal injury and the role it may play in the spread of tau after TBI. We propose that astrocytes play a crucial role by mediating both synapse loss and recovery. Finally, we highlight recent developments in the field including synapse molecular imaging, fluid biomarkers and therapeutics. In particular, we discuss advances in our understanding of synapse ersity and suggest that the new technology of synaptome mapping may prove useful in identifying synapses that are vulnerable or resistant to TBI.
Publisher: Elsevier BV
Date: 02-2005
Publisher: Elsevier BV
Date: 2006
Publisher: Elsevier
Date: 2016
Publisher: Cold Spring Harbor Laboratory
Date: 19-12-2018
DOI: 10.1101/500389
Abstract: Although molecular mechanisms underpinning specific behaviors have been described, whether there are mechanisms that orchestrate a behavioral repertoire is unknown. To test if the postsynaptic proteome of excitatory synapses could impart such a mechanism we conducted the largest genetic study of mammalian synapses yet undertaken. A repertoire of sixteen innate and learned behaviors was assessed from 290,850 measures in 55 lines of mutant mice carrying targeted mutations in the principal classes of postsynaptic proteins. Each innate and learned behavior used a different combination of proteins. These combinations were comprised of proteins that lified or attenuated the magnitude of each behavioral response. All behaviors required proteins found in PSD95 supercomplexes. We show the vertebrate increase in proteome complexity drove an expansion in behavioral repertoires and generated susceptibility to a wide range of diseases. Our results reveal a molecular mechanism that generates a versatile and complex behavioral repertoire that is central to human behavioral disorders.
Publisher: Frontiers Media SA
Date: 2008
Publisher: Springer Science and Business Media LLC
Date: 10-1991
DOI: 10.1038/353558A0
Abstract: Long-term potentiation (LTP) in the hippoc us is thought to contribute to memory formation. In the Ca1 region, LTP requires the NMDA (N-methyl-D-aspartate) receptor-dependent influx of Ca2+ and activation of serine and threonine protein kinases. Because of the high amount of protein tyrosine kinases in hippoc us and cerebellum, two regions implicated in learning and memory, we examined the possible additional requirement of tyrosine kinase activity in LTP. We first examined the specificity in brain of five inhibitors of tyrosine kinase and found that two of them, lavendustin A and genistein, showed substantially greater specificity for tyrosine kinase from hippoc us than for three serine-threonine kinases: protein kinase A, protein kinase C, and Ca2+/calmodulin kinase II. Lavendustin A and genistein selectively blocked the induction of LTP when applied in the bath or injected into the postsynaptic cell. By contrast, the inhibitors had no effect on the established LTP, on normal synaptic transmission, or on the neurotransmitter actions attributable to the actions of protein kinase A or protein kinase C. These data suggest that tyrosine kinase activity could be required postsynaptically for long-term synaptic plasticity in the hippoc us. As Ca2+ calmodulin kinase II or protein kinase C seem also to be required, the tyrosine kinases could participate postsynaptically in a kinase network together with serine and threonine kinases.
Publisher: Cold Spring Harbor Laboratory
Date: 10-2014
DOI: 10.1101/009845
Abstract: Background: Neural circuits can spontaneously generate complex spatiotemporal firing patterns during development. This spontaneous activity is thought to help guide development of the nervous system. In this study, we had two aims. First, to characterise the changes in spontaneous activity in cultures of developing networks of either hippoc al or cortical neurons dissociated from mouse. Second, to assess whether there are any functional differences in the patterns of activity in hippoc al and cortical networks. Results: We used multielectrode arrays to record the development of spontaneous activity in cultured networks of either hippoc al or cortical neurons every two or three days for the first month after plating. Within a few days of culturing, networks exhibited spontaneous activity. This activity strengthened and then stabilised typically around 21 days in vitro. We quantified the activity patterns in hippoc al and cortical networks using eleven features. Three out of eleven features showed striking differences in activity between hippoc al and cortical networks. 1: Interburst intervals are less variable in spike trains from hippoc al cultures. 2: Hippoc al networks have higher correlations. 3: Hippoc al networks generate more robust theta bursting patterns. Machine learning techniques confirmed that these differences in patterning are sufficient to reliably classify recordings at any given age as either hippoc al or cortical networks. Conclusions: Although cultured networks of hippoc al and cortical networks both generate spontaneous activity that changes over time, at any given time we can reliably detect differences in the activity patterns. We anticipate that this quantitative framework could have applications in many areas, including neurotoxicity testing and for characterising phenotype of different mutant mice. All code and data relating to this report are freely available for others to use.
Publisher: Oxford University Press (OUP)
Date: 2014
DOI: 10.1603/ME13105
Publisher: eLife Sciences Publications, Ltd
Date: 09-2023
Publisher: Society for Neuroscience
Date: 07-03-2007
DOI: 10.1523/JNEUROSCI.4457-06.2007
Abstract: Understanding the mechanisms whereby information encoded within patterns of action potentials is deciphered by neurons is central to cognitive psychology. The multiprotein complexes formed by NMDA receptors linked to synaptic membrane-associated guanylate kinase (MAGUK) proteins including synapse-associated protein 102 (SAP102) and other associated proteins are instrumental in these processes. Although humans with mutations in SAP102 show mental retardation, the physiological and biochemical mechanisms involved are unknown. Using SAP102 knock-out mice, we found specific impairments in synaptic plasticity induced by selective frequencies of stimulation that also required extracellular signal-regulated kinase signaling. This was paralleled by inflexibility and impairment in spatial learning. Improvement in spatial learning performance occurred with extra training despite continued use of a suboptimal search strategy, and, in a separate nonspatial task, the mutants again deployed a different strategy. Double-mutant analysis of postsynaptic density-95 and SAP102 mutants indicate overlapping and specific functions of the two MAGUKs. These in vivo data support the model that specific MAGUK proteins couple the NMDA receptor to distinct downstream signaling pathways. This provides a mechanism for discriminating patterns of synaptic activity that lead to long-lasting changes in synaptic strength as well as distinct aspects of cognition in the mammalian nervous system.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2018
DOI: 10.1038/S41598-017-18640-Z
Abstract: The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.NEUROPHARM.2019.02.035
Abstract: Inhibition of postsynaptic density protein-95 (PSD-95) decouples N-methyl-d-aspartate (NMDA) receptor downstream signaling and results in neuroprotection after focal cerebral ischemia. We have previously developed UCCB01-144, a dimeric PSD-95 inhibitor, which binds PSD-95 with high affinity and is neuroprotective in experimental stroke. Here, we investigate the selectivity, efficacy and toxicity of UCCB01-144 and compare with the monomeric drug candidate Tat-NR2B9c. Fluorescence polarization using purified proteins and pull-downs of mouse brain lysates showed that UCCB01-144 potently binds all four PSD-95-like membrane-associated guanylate kinases (MAGUKs). In addition, UCCB01-144 affected NMDA receptor signaling pathways in ischemic brain tissue. UCCB01-144 reduced infarct size in young and aged male mice at various doses when administered 30 min after permanent middle cerebral artery occlusion, but UCCB01-144 was not effective in young male mice when administered 1 h post-ischemia or in female mice. Furthermore, UCCB01-144 was neuroprotective in a transient stroke model in rats, and in contrast to Tat-NR2B9c, high dose of UCCB01-144 did not lead to significant changes in mean arterial blood pressure or heart rate. Overall, UCCB01-144 is a potent MAGUK inhibitor that reduces neurotoxic PSD-95-mediated signaling and improves neuronal survival following focal brain ischemia in rodents under various conditions and without causing cardiovascular side effects, which encourages further studies towards clinical stroke trials.
Publisher: Wiley
Date: 19-07-2019
DOI: 10.1002/NPR2.12073
Publisher: Proceedings of the National Academy of Sciences
Date: 12-1988
Abstract: Three pancreatic beta-cell lines have been established from insulinomas derived from transgenic mice carrying a hybrid insulin-promoted simian virus 40 tumor antigen gene. The beta tumor cell (beta TC) lines maintain the features of differentiated beta cells for about 50 passages in culture. The cells produce both proinsulin I and II and efficiently process each into mature insulin, in a manner comparable to normal beta cells in isolated islets. Electron microscopy reveals typical beta-cell type secretory granules, in which insulin is stored. Insulin secretion is inducible up to 30-fold by glucose, although with a lower threshold for maximal stimulation than that for normal beta cells. beta TC lines can be repeatedly derived from primary beta-cell tumors that heritably arise in the transgenic mice. Thus, targeted expression of an oncogene with a cell-specific regulatory element can be used both to immortalize a rare cell type and to provide a selection for the maintenance of its differentiated phenotype.
Publisher: Cold Spring Harbor Laboratory
Date: 18-01-2020
DOI: 10.1101/2020.01.17.910547
Abstract: Large-scale mapping of the location of synapses and their molecular properties in the mouse has shown that erse synapse types are spatially distributed across the brain. The ersity of synapses is known as the synaptome and the spatial distribution as the synaptome architecture. Synaptome maps in the mouse show each brain region has a characteristic compositional signature. The signature can store behavioral representations and is modified in mouse genetic models of human disease. The human synaptome remains unexplored and whether it has any conserved features with the mouse synaptome is unknown. As a first step toward creating a human synaptome atlas, we have labelled and imaged synapses expressing the excitatory synapse protein PSD95 in twenty human brain regions in four phenotypically normal in iduals. We quantified the number, size and intensity of approximately a billion in idual synaptic puncta and compared their regional distributions. We found that each region showed a distinct signature of synaptic puncta parameters. Comparison of brain regions showed the synaptome of cortical and hippoc al structures were similar but distinct to the synaptome of cerebellum and brainstem. Comparison of human and mouse synaptome revealed conservation of synaptic puncta parameters, hierarchical organization of brain regions and network architecture. These data show that the synaptome of humans and mouse share conserved features despite the 1000-fold difference in brain size and 90 million years since a common ancestor. This first draft human synaptome atlas illustrates the feasibility of generating a systematic atlas of the human synaptome in health and disease.
Publisher: SAGE Publications
Date: 2018
Abstract: Synapses are the hallmark of brain complexity and have long been thought of as simple connectors between neurons. We are now in an era in which we know the full complement of synapse proteins and this has created an existential crisis because the molecular complexity far exceeds the requirements of most simple models of synaptic function. Studies of the organisation of proteome complexity and its evolution provide surprising new insights that challenge existing dogma and promote the development of new theories about the origins and role of synapses in behaviour. The postsynaptic proteome of excitatory synapses is a structure with high molecular complexity and sophisticated computational properties that is disrupted in over 130 brain diseases. A key goal of 21st-century neuroscience is to develop comprehensive molecular datasets on the brain and develop theories that explain the molecular basis of behaviour.
Publisher: Society for Neuroscience
Date: 15-11-2002
Publisher: Rockefeller University Press
Date: 22-01-2007
Abstract: Signaling by laminins and axonal neuregulin has been implicated in regulating axon sorting by myelin-forming Schwann cells. However, the signal transduction mechanisms are unknown. Focal adhesion kinase (FAK) has been linked to α6β1 integrin and ErbB receptor signaling, and we show that myelination by Schwann cells lacking FAK is severely impaired. Mutant Schwann cells could interdigitate between axon bundles, indicating that FAK signaling was not required for process extension. However, Schwann cell FAK was required to stimulate cell proliferation, suggesting that amyelination was caused by insufficient Schwann cells. ErbB2 receptor and AKT were robustly phosphorylated in mutant Schwann cells, indicating that neuregulin signaling from axons was unimpaired. These findings demonstrate the vital relationship between axon defasciculation and Schwann cell number and show the importance of FAK in regulating cell proliferation in the developing nervous system.
Publisher: Elsevier BV
Date: 12-2008
Publisher: Informa UK Limited
Date: 22-04-2014
Publisher: Springer Science and Business Media LLC
Date: 08-04-2007
DOI: 10.1038/NN1893
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 04-2023
DOI: 10.1016/J.SEMCDB.2022.05.028
Abstract: Synapse loss and damage are central features of Alzheimer's disease (AD) and contribute to the onset and progression of its behavioural and physiological features. Here we review the literature describing synapse pathology in AD, from what we have learned from microscopy in terms of its impacts on synapse architecture, to the mechanistic role of Aβ, tau and glial cells, mitochondrial dysfunction, and the link with AD risk genes. We consider the emerging view that synapse pathology may operate at a further level, that of synapse ersity, and discuss the prospects for leveraging new synaptome mapping methods to comprehensively understand the molecular properties of vulnerable and resilient synapses. Uncovering AD impacts on brain synapse ersity should inform therapeutic approaches targeted at preserving or replenishing lost and damaged synapses and aid the interpretation of clinical imaging approaches that aim to measure synapse damage.
Publisher: Wiley
Date: 12-12-2008
Publisher: Research Square Platform LLC
Date: 14-04-2022
DOI: 10.21203/RS.3.RS-1508559/V1
Abstract: Neurodevelopmental disorders of genetic origin delay the acquisition of normal abilities and cause disabling phenotypes. However, spontaneous attenuation and even complete amelioration of symptoms in early childhood and adolescence occur in many disorders, suggesting that brain circuits possess an intrinsic capacity to overcome some germline mutations. We examined the molecular composition of almost a trillion excitatory synapses on a brain-wide scale between birth and adulthood in mice carrying a mutation in the homeobox transcription factor Pax6, a neurodevelopmental disorder model. Pax6 haploinsufficiency had no impact on total synapse number at any age. By contrast, the molecular composition of excitatory synapses, the postnatal expansion of synapse ersity and the acquisition of normal synaptome architecture were delayed in all brain regions, interfering with network and cognitive functions. Specific excitatory synapse types and subtypes were affected in two key developmental age-windows. These phenotypes were reversed within 2-3 weeks of onset, restoring synapse ersity and synaptome architecture to the normal developmental trajectory. Synapse subtypes with rapid protein turnover mediated the synaptome remodeling. This brain-wide capacity for remodeling of synapse molecular composition to recover and maintain the developmental trajectory of synaptome architecture may help confer resilience to neurodevelopmental genetic disorders.
Publisher: Elsevier BV
Date: 10-2013
Publisher: Elsevier BV
Date: 03-1993
DOI: 10.1016/0896-6273(93)90331-K
Abstract: One of the hallmarks of long-term memory in both vertebrates and invertebrates is the requirement for new protein synthesis. In sensitization of the gill-withdrawal reflex in Aplysia, this requirement can be studied on the cellular level. Here, long-term but not short-term facilitation of the monosynaptic connections between the sensory and motor neurons requires new protein synthesis and is reflected in an altered level of expression of specific proteins regulated through the cAMP second-messenger pathway. Using gene transfer into in idual sensory neurons of Aplysia, we find that serotonin (5-HT) induces transcriptional activation of a lacZ reporter gene driven by the cAMP response element (CRE) and that this induction requires CRE-binding proteins (CREBs). The induction by 5-HT does not occur following a single pulse, but becomes progressively more effective following two or more pulses. Moreover, expression of GAL4-CREB fusion genes shows that 5-HT induction requires phosphorylation of CREB on Ser119 by protein kinase A. These data provide direct evidence for CREB-modulated transcriptional activation with long-term facilitation.
Publisher: Cold Spring Harbor Laboratory
Date: 21-01-2011
DOI: 10.1101/LM.2045311
Abstract: Through protein interactions mediated by their cytoplasmic C termini the GluN2A and GluN2B subunits of NMDA receptors (NMDARs) have a key role in the formation of NMDAR signaling complexes at excitatory synapses. Although these signaling complexes are thought to have a crucial role in NMDAR-dependent forms of synaptic plasticity such as long-term potentiation (LTP), the role of the C terminus of GluN2A in coupling NMDARs to LTP enhancing and/or suppressing signaling pathways is unclear. To address this issue we examined the induction of LTP in the hippoc al CA1 region in mice lacking the C terminus of endogenous GluN2A subunits (GluN2A ΔC/ΔC ). Our results show that truncation of GluN2A subunits produces robust, but highly frequency-dependent, deficits in LTP and a reduction in basal levels of extracellular signal regulated kinase 2 (ERK2) activation and phosphorylation of AMPA receptor GluA1 subunits at a protein kinase A site (serine 845). Consistent with the notion that these signaling deficits contribute to the deficits in LTP in GluN2A ΔC/ΔC mice, activating ERK2 and increasing GluA1 S845 phosphorylation through activation of β-adrenergic receptors rescued the induction of LTP in these mutants. Together, our results indicate that the capacity of excitatory synapses to undergo plasticity in response to different patterns of activity is dependent on the coupling of specific signaling pathways to the intracellular domains of the NMDARs and that abnormal plasticity resulting from mutations in NMDARs can be reduced by activation of key neuromodulatory transmitter receptors that engage converging signaling pathways.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2021
Publisher: The Royal Society
Date: 05-01-2016
Abstract: How the sophisticated vertebrate behavioural repertoire evolved remains a major question in biology. The behavioural repertoire encompasses the set of in idual behavioural components that an organism uses when adapting and responding to changes in its external world. Although unicellular organisms, invertebrates and vertebrates share simple reflex responses, the fundamental mechanisms that resulted in the complexity and sophistication that is characteristic of vertebrate behaviours have only recently been examined. A series of behavioural genetic experiments in mice and humans support a theory that posited the importance of synapse proteome expansion in generating complexity in the behavioural repertoire. Genome duplication events, approximately 550 Ma, produced expansion in the synapse proteome that resulted in increased complexity in synapse signalling mechanisms that regulate components of the behavioural repertoire. The experiments demonstrate the importance to behaviour of the gene duplication events, the ersification of paralogues and sequence constraint. They also confirm the significance of comparative proteomic and genomic studies that identified the molecular origins of synapses in unicellular eukaryotes and the vertebrate expansion in proteome complexity. These molecular mechanisms have general importance for understanding the repertoire of behaviours in different species and for human behavioural disorders arising from synapse gene mutations.
Publisher: Portland Press Ltd.
Date: 20-01-2006
DOI: 10.1042/BST0340059
Abstract: Synapse proteomics has recently resulted in a quantum leap in knowledge of the protein composition of brain synapses and its phosphorylation. We now have the first draft picture of the synapse, comprising ∼1000 proteins. This is not matched by available methods of functional analysis either in reduced systems or in whole animals. Fewer than 20% of synapse proteome proteins have a known function in the nervous system. A concerted effort is required to establish new technical approaches before we can understand the ersity of functions conferred by the synapse proteome on the synapse, the neuron and the animal. This review will highlight this change in knowledge and discuss current technical and interpretative limitations challenged by synapse proteomics.
Publisher: Elsevier BV
Date: 10-1995
DOI: 10.1016/0920-1211(95)00029-1
Abstract: To identify specific genes involved with epileptogenesis kindling was examined in mice carrying mutations engineered by gene targeting. Amygdala kindling was tested in mice with a null-mutation in the Fyn tyrosine kinase gene, a mutation that raises the threshold for the induction of long-term potentiation in the hippoc us. The fyn mutants had a normal threshold, duration and stability of epileptiform after-discharge, which is crucial for kindling. Despite the normal after-discharge, fyn mutants showed a striking retardation in the rate of kindling. Once the kindled state was established in fyn mutants it remained stable. This implicates a Fyn-dependent biochemical pathway in the induction but not the maintenance of normal amygdala kindling. fyn is the first gene identified to be required for normal epileptogenesis.
Publisher: American Psychological Association
Date: 2003
DOI: 10.1037/10480-008
Publisher: Proceedings of the National Academy of Sciences
Date: 02-1992
Abstract: Although potassium channels play a variety of roles in shaping the electrical properties of neurons, little is known about how these channels are constituted in neurons. To examine the assembly and physiological function of A-type K+ channels in mature differentiated neurons, we have developed a highly efficient gene transfer method for Aplysia neurons that has allowed us to express about 10(7) copies of the cloned Aplysia Shaker (Sh) K+ channel (AK01a) in single identified cells. We find that expression of AK01a phenocopies one of the native transient K+ currents (IAdepol), suggesting that the native channel carrying IAdepol is assembled as a homooligomer of AK01a. Overexpression of AK01a has substantial effect on the action potential, shortening its duration, enhancing its hyperpolarizing afterpotential, and depressing by more than half the amount of transmitter release by the action potential from the terminals. Thus, the AK01a channel not only contributes to the firing properties within a given neuron but also can regulate the signaling between interconnected cells.
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 05-2007
Publisher: Elsevier BV
Date: 02-1994
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.MOLBRAINRES.2004.09.024
Abstract: Postsynaptic density-95 (PSD-95) is an evolutionarily conserved synaptic adaptor protein that is known to bind many proteins including the NMDA receptor. This observation has implicated it in many NMDA receptor-dependent processes including spatial learning and synaptic plasticity. We have cloned and characterised the murine PSD-95 gene. In addition, we have identified two previously uncharacterised splice variants of the major murine PSD-95 transcript (PSD-95alpha): PSD-95alpha-2b results from an extension of exon 2 and PSD-95alpha-Delta18 from the temporal exclusion of exon 18. The presence of PSD-95alpha-2b sequences in other PSD-95 family members implicates this peptide stretch as functionally significant. Another potential transcript (PSD-95gamma) was also identified based on examination of EST databases. Immunoprecipitation assays demonstrate that proteins corresponding in size to PSD-95alpha-Delta18 and PSD-95gamma interact with the NMDA receptor, suggesting an important biological role for these isoforms. Finally, we have performed bioinformatics analyses of the PSD-95 mRNA untranslated regions, identifying multiple translational control elements that suggest protein production could be regulated post-transcriptionally. The variety of mRNA isoforms and regulatory elements identified provides for a high degree of ersity in the structure and function of PSD-95 proteins.
Publisher: Wiley
Date: 2018
DOI: 10.1111/EJN.13792
Abstract: PSD-95 is one of the most abundant proteins of the postsynaptic density of excitatory synapses. It functions as the backbone of protein supercomplexes that mediate signalling between membrane glutamate receptors and intracellular pathways. Homozygous deletion of the Dlg4 gene encoding PSD-95 was previously found to cause a profound impairment in operant and Pavlovian conditioning in Dlg4
Publisher: Cold Spring Harbor Laboratory
Date: 03-02-2021
DOI: 10.1101/2021.02.02.428362
Abstract: Increased levels of lactate, an end-product of glycolysis, have been proposed as a potential surrogate marker for metabolic changes during neuronal excitation. These changes in lactate levels can result in decreased brain pH, which has been implicated in patients with various neuropsychiatric disorders. We previously demonstrated that such alterations are commonly observed in five mouse models of schizophrenia, bipolar disorder, and autism, suggesting a shared endophenotype among these disorders rather than mere artifacts due to medications or agonal state. However, there is still limited research on this phenomenon in animal models, leaving its generality across other disease animal models uncertain. Moreover, the association between changes in brain lactate levels and specific behavioral abnormalities remains unclear. To address these gaps, the International Brain pH Project Consortium investigated brain pH and lactate levels in 109 strains/conditions of 2,294 animals with genetic and other experimental manipulations relevant to neuropsychiatric disorders. Systematic analysis revealed that decreased brain pH and increased lactate levels were common features observed in multiple models of depression, epilepsy, Alzheimer’s disease, and some additional schizophrenia models. While certain autism models also exhibited decreased pH and increased lactate levels, others showed the opposite pattern, potentially reflecting subpopulations within the autism spectrum. Furthermore, utilizing large-scale behavioral test battery, a multivariate cross-validated prediction analysis demonstrated that poor working memory performance was predominantly associated with increased brain lactate levels. Importantly, this association was confirmed in an independent cohort of animal models. Collectively, these findings suggest that altered brain pH and lactate levels, which could be attributed to dysregulated excitation/inhibition balance, may serve as transdiagnostic endophenotypes of debilitating neuropsychiatric disorders characterized by cognitive impairment, irrespective of their beneficial or detrimental nature.
Publisher: Wiley
Date: 04-2001
Publisher: Springer Science and Business Media LLC
Date: 16-12-2014
DOI: 10.1038/MP.2014.161
Publisher: Springer Science and Business Media LLC
Date: 29-01-2010
Abstract: Sothern blotting is a DNA analysis technique that has found widespread application in molecular biology. It has been used for gene discovery and mapping and has diagnostic and forensic applications, including mutation detection in patient s les and DNA fingerprinting in criminal investigations. Southern blotting has been employed as the definitive method for detecting transgene integration, and successful homologous recombination in gene targeting experiments. The technique employs a labeled DNA probe to detect a specific DNA sequence in a complex DNA s le that has been separated by restriction-digest and gel electrophoresis. Critically for the technique to succeed the probe must be unique to the target locus so as not to cross-hybridize to other endogenous DNA within the s le. Investigators routinely employ a manual approach to probe design. A genome browser is used to extract DNA sequence from the locus of interest, which is searched against the target genome using a BLAST-like tool. Ideally a single perfect match is obtained to the target, with little cross-reactivity caused by homologous DNA sequence present in the genome and/or repetitive and low-complexity elements in the candidate probe. This is a labor intensive process often requiring several attempts to find a suitable probe for laboratory testing. We have written an informatic pipeline to automatically design genomic Sothern blot probes that specifically attempts to optimize the resultant probe, employing a brute-force strategy of generating many candidate probes of acceptable length in the user-specified design window, searching all against the target genome, then scoring and ranking the candidates by uniqueness and repetitive DNA element content. Using these in silico measures we can automatically design probes that we predict to perform as well, or better, than our previous manual designs, while considerably reducing design time. We went on to experimentally validate a number of these automated designs by Southern blotting. The majority of probes we tested performed well confirming our in silico prediction methodology and the general usefulness of the software for automated genomic Southern probe design. Software and supplementary information are freely available at: oftware/southern_blot
Publisher: Society for Neuroscience
Date: 11-11-2015
DOI: 10.1523/JNEUROSCI.1087-15.2015
Abstract: Previous studies have hypothesized that erse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap +/− and Fmr1 −/ y mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap +/− hippoc al slices. Super-resolution microscopy reveals that Syngap +/− and Fmr1 −/ y mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras–ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency. SIGNIFICANCE STATEMENT As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically ergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap +/− mice phenocopy Fmr1 −/ y mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu 5 receptor–ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1 −/ y mice. Our findings support the hypothesis that phenotypes associated with genetically erse forms of ID/ASDs result from alterations in common cellular/biochemical pathways.
Publisher: Elsevier BV
Date: 12-2022
DOI: 10.1016/J.NEURON.2022.09.009
Abstract: The lifetime of proteins in synapses is important for their signaling, maintenance, and remodeling, and for memory duration. We quantified the lifetime of endogenous PSD95, an abundant postsynaptic protein in excitatory synapses, at single-synapse resolution across the mouse brain and lifespan, generating the Protein Lifetime Synaptome Atlas. Excitatory synapses have a wide range of PSD95 lifetimes extending from hours to several months, with distinct spatial distributions in dendrites, neurons, and brain regions. Synapses with short protein lifetimes are enriched in young animals and in brain regions controlling innate behaviors, whereas synapses with long protein lifetimes accumulate during development, are enriched in the cortex and CA1 where memories are stored, and are preferentially preserved in old age. Synapse protein lifetime increases throughout the brain in a mouse model of autism and schizophrenia. Protein lifetime adds a further layer to synapse ersity and enriches prevailing concepts in brain development, aging, and disease.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2017
End Date: 2020
Funder: Wellcome Trust
View Funded ActivityStart Date: 2005
End Date: 2008
Funder: International Human Frontier Science Program Organization
View Funded ActivityStart Date: 2016
End Date: 2020
Funder: European Research Council
View Funded ActivityStart Date: 2010
End Date: 2015
Funder: Medical Research Council
View Funded ActivityStart Date: 2013
End Date: 2016
Funder: Medical Research Council
View Funded ActivityStart Date: 2000
End Date: 2004
Funder: Wellcome Trust
View Funded ActivityStart Date: 2010
End Date: 2015
Funder: Seventh Framework Programme
View Funded ActivityStart Date: 2009
End Date: 2014
Funder: H2020 European Research Council
View Funded ActivityStart Date: 2013
End Date: 2016
Funder: European Commission
View Funded ActivityStart Date: 2015
End Date: 2017
Funder: Medical Research Council
View Funded ActivityStart Date: 2004
End Date: 2007
Funder: Medical Research Council
View Funded ActivityStart Date: 2002
End Date: 2006
Funder: Wellcome Trust
View Funded ActivityStart Date: 2020
End Date: 2025
Funder: European Research Council
View Funded ActivityStart Date: 2020
End Date: 2024
Funder: Wellcome Trust
View Funded ActivityStart Date: 2016
End Date: 2017
Funder: F. Hoffmann-La Roche
View Funded ActivityStart Date: 2018
End Date: 2020
Funder: Simons Foundation
View Funded ActivityStart Date: 2018
End Date: 2019
Funder: Wellcome Trust
View Funded Activity