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Voerman S, Broersen R, Swagemakers SMA, De Zeeuw CI, van der Spek PJ. Plasticity mechanisms of genetically distinct Purkinje cells. Bioessays 2024:e2400008. [PMID: 38697917 DOI: 10.1002/bies.202400008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/04/2024] [Accepted: 04/05/2024] [Indexed: 05/05/2024]
Abstract
Despite its uniform appearance, the cerebellar cortex is highly heterogeneous in terms of structure, genetics and physiology. Purkinje cells (PCs), the principal and sole output neurons of the cerebellar cortex, can be categorized into multiple populations that differentially express molecular markers and display distinctive physiological features. Such features include action potential rate, but also their propensity for synaptic and intrinsic plasticity. However, the precise molecular and genetic factors that correlate with the differential physiological properties of PCs remain elusive. In this article, we provide a detailed overview of the cellular mechanisms that regulate PC activity and plasticity. We further perform a pathway analysis to highlight how molecular characteristics of specific PC populations may influence their physiology and plasticity mechanisms.
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Affiliation(s)
- Stijn Voerman
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Robin Broersen
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Sigrid M A Swagemakers
- Department of Pathology and Clinical Bioinformatics, Erasmus MC, Rotterdam, The Netherlands
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Peter J van der Spek
- Department of Pathology and Clinical Bioinformatics, Erasmus MC, Rotterdam, The Netherlands
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2
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Vogt K, Kulkarni A, Pandey R, Dehnad M, Konopka G, Greene R. Sleep need driven oscillation of glutamate synaptic phenotype. bioRxiv 2024:2024.02.05.578985. [PMID: 38370691 PMCID: PMC10871195 DOI: 10.1101/2024.02.05.578985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Sleep loss increases AMPA-synaptic strength and number in the neocortex. However, this is only part of the synaptic sleep loss response. We report increased AMPA/NMDA EPSC ratio in frontal-cortical pyramidal neurons of layers 2-3. Silent synapses are absent, decreasing the plastic potential to convert silent NMDA to active AMPA synapses. These sleep loss changes are recovered by sleep. Sleep genes are enriched for synaptic shaping cellular components controlling glutamate synapse phenotype, overlap with autism risk genes and are primarily observed in excitatory pyramidal neurons projecting intra-telencephalically. These genes are enriched with genes controlled by the transcription factor, MEF2c and its repressor, HDAC4. Thus, sleep genes under the influence of MEF2c and HDAC4, can provide a framework within which motor learning and training occurs mediated by sleep-dependent oscillation of glutamate-synaptic phenotypes.
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Affiliation(s)
- K.E. Vogt
- International Institute of Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
| | - A. Kulkarni
- Department of Neuroscience, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - R. Pandey
- Department of Psychiatry, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - M. Dehnad
- Department of Psychiatry, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - G. Konopka
- Department of Neuroscience, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - R.W. Greene
- International Institute of Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Japan
- Department of Neuroscience, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
- Department of Psychiatry, Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, United States
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3
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Xue T, Liu W, Wang L, Shi Y, Hu Y, Yang J, Li G, Huang H, Cui D. Extracellular vesicle biomarkers for complement dysfunction in schizophrenia. Brain 2024; 147:1075-1086. [PMID: 37816260 PMCID: PMC10907082 DOI: 10.1093/brain/awad341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/17/2023] [Accepted: 09/19/2023] [Indexed: 10/12/2023] Open
Abstract
Schizophrenia, a complex neuropsychiatric disorder, frequently experiences a high rate of misdiagnosis due to subjective symptom assessment. Consequently, there is an urgent need for innovative and objective diagnostic tools. In this study, we used cutting-edge extracellular vesicles' (EVs) proteome profiling and XGBoost-based machine learning to develop new markers and personalized discrimination scores for schizophrenia diagnosis and prediction of treatment response. We analysed plasma and plasma-derived EVs from 343 participants, including 100 individuals with chronic schizophrenia, 34 first-episode and drug-naïve patients, 35 individuals with bipolar disorder, 25 individuals with major depressive disorder and 149 age- and sex-matched healthy controls. Our innovative approach uncovered EVs-based complement changes in patients, specific to their disease-type and status. The EV-based biomarkers outperformed their plasma counterparts, accurately distinguishing schizophrenia individuals from healthy controls with an area under curve (AUC) of 0.895, 83.5% accuracy, 85.3% sensitivity and 82.0% specificity. Moreover, they effectively differentiated schizophrenia from bipolar disorder and major depressive disorder, with AUCs of 0.966 and 0.893, respectively. The personalized discrimination scores provided a personalized diagnostic index for schizophrenia and exhibited a significant association with patients' antipsychotic treatment response in the follow-up cohort. Overall, our study represents a significant advancement in the field of neuropsychiatric disorders, demonstrating the potential of EV-based biomarkers in guiding personalized diagnosis and treatment of schizophrenia.
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Affiliation(s)
- Ting Xue
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 201108, China
- Shanghai Key Laboratory of Psychotic Disorders, Brain Health Institute, Shanghai Mental Health Center, Shanghai 201108, China
| | - Wenxin Liu
- College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Lijun Wang
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 201108, China
- Shanghai Key Laboratory of Psychotic Disorders, Brain Health Institute, Shanghai Mental Health Center, Shanghai 201108, China
| | - Yuan Shi
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 201108, China
- Shanghai Key Laboratory of Psychotic Disorders, Brain Health Institute, Shanghai Mental Health Center, Shanghai 201108, China
| | - Ying Hu
- Shenzhi Department, Fourth Affiliated Hospital of Xinjiang Medical University, Urumqi 830000, China
| | - Jing Yang
- Department of Hematology, Tongji Hospital, Frontier Science Center for Stem Cell Research, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Guiming Li
- Department of Hematology, Tongji Hospital, Frontier Science Center for Stem Cell Research, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Hongna Huang
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 201108, China
- Shanghai Key Laboratory of Psychotic Disorders, Brain Health Institute, Shanghai Mental Health Center, Shanghai 201108, China
| | - Donghong Cui
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 201108, China
- Shanghai Key Laboratory of Psychotic Disorders, Brain Health Institute, Shanghai Mental Health Center, Shanghai 201108, China
- Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai 200240, China
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Traenkner D, Shennib O, Johnson A, Weinbrom A, Taylor MR, Williams ME. Modular Splicing Is Linked to Evolution in the Synapse-Specificity Molecule Kirrel3. eNeuro 2023; 10:ENEURO.0253-23.2023. [PMID: 37977826 DOI: 10.1523/eneuro.0253-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 11/19/2023] Open
Abstract
Kirrel3 is a cell-adhesion molecule that instructs the formation of specific synapses during brain development in mouse and Kirrel3 variants may be risk factors for autism and intellectual disabilities in humans. Kirrel3 is predicted to undergo alternative splicing but brain isoforms have not been studied. Here, we present the first in-depth characterization of Kirrel3 isoform diversity in brain using targeted, long-read mRNA sequencing of mouse hippocampus. We identified 19 isoforms with predicted transmembrane and secreted forms and show that even rare isoforms generate detectable protein in the brain. We also analyzed publicly-available long-read mRNA databases from human brain tissue and found 11 Kirrel3 isoforms that, similar to mouse, encode transmembrane and secreted forms. In mice and humans, Kirrel3 diversity arises from alternative, independent use of protein-domain coding exons and alternative early translation-stop signals. Intriguingly, the alternatively spliced exons appear at branch points in the chordate phylogenetic tree, including one exon only found in humans and their closest living relatives, the great apes. Together, these results validate a simple pipeline for analyzing isoform diversity in genes with low expression and suggest that Kirrel3 function is fine-tuned by alternative splicing and may play a role in brain evolution.
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Affiliation(s)
- Dimitri Traenkner
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
| | - Omar Shennib
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
| | - Alyssa Johnson
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
| | - Adam Weinbrom
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
| | - Matthew R Taylor
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
| | - Megan E Williams
- Department of Neurobiology, University of Utah, School of Medicine, Salt Lake City, UT 84112
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Cording KR, Bateup HS. Altered motor learning and coordination in mouse models of autism spectrum disorder. Front Cell Neurosci 2023; 17:1270489. [PMID: 38026686 PMCID: PMC10663323 DOI: 10.3389/fncel.2023.1270489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 12/01/2023] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing prevalence. Over 1,000 risk genes have now been implicated in ASD, suggesting diverse etiology. However, the diagnostic criteria for the disorder still comprise two major behavioral domains - deficits in social communication and interaction, and the presence of restricted and repetitive patterns of behavior (RRBs). The RRBs associated with ASD include both stereotyped repetitive movements and other motor manifestations including changes in gait, balance, coordination, and motor skill learning. In recent years, the striatum, the primary input center of the basal ganglia, has been implicated in these ASD-associated motor behaviors, due to the striatum's role in action selection, motor learning, and habit formation. Numerous mouse models with mutations in ASD risk genes have been developed and shown to have alterations in ASD-relevant behaviors. One commonly used assay, the accelerating rotarod, allows for assessment of both basic motor coordination and motor skill learning. In this corticostriatal-dependent task, mice walk on a rotating rod that gradually increases in speed. In the extended version of this task, mice engage striatal-dependent learning mechanisms to optimize their motor routine and stay on the rod for longer periods. This review summarizes the findings of studies examining rotarod performance across a range of ASD mouse models, and the resulting implications for the involvement of striatal circuits in ASD-related motor behaviors. While performance in this task is not uniform across mouse models, there is a cohort of models that show increased rotarod performance. A growing number of studies suggest that this increased propensity to learn a fixed motor routine may reflect a common enhancement of corticostriatal drive across a subset of mice with mutations in ASD-risk genes.
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Affiliation(s)
- Katherine R. Cording
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
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6
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Shih YT, Alipio JB, Sahay A. An inhibitory circuit-based enhancer of DYRK1A function reverses Dyrk1a-associated impairment in social recognition. Neuron 2023; 111:3084-3101.e5. [PMID: 37797581 PMCID: PMC10575685 DOI: 10.1016/j.neuron.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/29/2023] [Accepted: 09/07/2023] [Indexed: 10/07/2023]
Abstract
Heterozygous mutations in the dual-specificity tyrosine phosphorylation-regulated kinase 1a (Dyrk1a) gene define a syndromic form of autism spectrum disorder. The synaptic and circuit mechanisms mediating DYRK1A functions in social cognition are unclear. Here, we identify a social experience-sensitive mechanism in hippocampal mossy fiber-parvalbumin interneuron (PV IN) synapses by which DYRK1A recruits feedforward inhibition of CA3 and CA2 to promote social recognition. We employ genetic epistasis logic to identify a cytoskeletal protein, ABLIM3, as a synaptic substrate of DYRK1A. We demonstrate that Ablim3 downregulation in dentate granule cells of adult heterozygous Dyrk1a mice is sufficient to restore PV IN-mediated inhibition of CA3 and CA2 and social recognition. Acute chemogenetic activation of PV INs in CA3/CA2 of adult heterozygous Dyrk1a mice also rescued social recognition. Together, these findings illustrate how targeting DYRK1A synaptic and circuit substrates as "enhancers of DYRK1A function" harbors the potential to reverse Dyrk1a haploinsufficiency-associated circuit and cognition impairments.
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Affiliation(s)
- Yu-Tzu Shih
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; BROAD Institute of Harvard and MIT, Cambridge, MA, USA
| | - Jason Bondoc Alipio
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; BROAD Institute of Harvard and MIT, Cambridge, MA, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; BROAD Institute of Harvard and MIT, Cambridge, MA, USA.
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7
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Sah S, Keable R, Pfundstein G, Clemens KJ, Begg D, Schachner M, Leshchyns'ka I, Sytnyk V. Deficiency in the neural cell adhesion molecule 2 (NCAM2) reduces axonal levels of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), affects axonal organization in the hippocampus, and leads to behavioral deficits. Cereb Cortex 2023; 33:10047-10065. [PMID: 37522285 DOI: 10.1093/cercor/bhad264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 06/25/2023] [Accepted: 01/26/2023] [Indexed: 08/01/2023] Open
Abstract
The neural cell adhesion molecule 2 (NCAM2) regulates axonal organization in the central nervous system via mechanisms that have remained poorly understood. We now show that NCAM2 increases axonal levels of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), a protease that regulates axonal guidance. In brains of NCAM2-deficient mice, BACE1 levels are reduced in hippocampal mossy fiber projections, and the infrapyramidal bundle of these projections is shortened. This abnormal axonal organization correlates with impaired short-term spatial memory and cognitive flexibility in NCAM2-deficient male and female mice. Self-grooming, rearing, digging and olfactory acuity are increased in NCAM2-deficient male mice, when compared with littermate wild-type mice of the same sex. NCAM2-deficient female mice also show increased self-grooming, but are reduced in rearing, and do not differ from female wild-type mice in olfactory acuity and digging behavior. Our results indicate that errors in axonal guidance and organization caused by impaired BACE1 function can underlie the manifestation of neurodevelopmental disorders, including autism as found in humans with deletions of the NCAM2 gene.
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Affiliation(s)
- Saroj Sah
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Ryan Keable
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Grant Pfundstein
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Kelly J Clemens
- School of Psychology, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Denovan Begg
- School of Psychology, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08554, United States
| | - Iryna Leshchyns'ka
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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Papp C, Mukundan VT, Jenjaroenpun P, Winnerdy FR, Ow GS, Phan AT, Kuznetsov VA. Stable bulged G-quadruplexes in the human genome: identification, experimental validation and functionalization. Nucleic Acids Res 2023; 51:4148-4177. [PMID: 37094040 DOI: 10.1093/nar/gkad252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/23/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023] Open
Abstract
DNA sequence composition determines the topology and stability of G-quadruplexes (G4s). Bulged G-quadruplex structures (G4-Bs) are a subset of G4s characterized by 3D conformations with bulges. Current search algorithms fail to capture stable G4-B, making their genome-wide study infeasible. Here, we introduced a large family of computationally defined and experimentally verified potential G4-B forming sequences (pG4-BS). We found 478 263 pG4-BS regions that do not overlap 'canonical' G4-forming sequences in the human genome and are preferentially localized in transcription regulatory regions including R-loops and open chromatin. Over 90% of protein-coding genes contain pG4-BS in their promoter or gene body. We observed generally higher pG4-BS content in R-loops and their flanks, longer genes that are associated with brain tissue, immune and developmental processes. Also, the presence of pG4-BS on both template and non-template strands in promoters is associated with oncogenesis, cardiovascular disease and stemness. Our G4-BS models predicted G4-forming ability in vitro with 91.5% accuracy. Analysis of G4-seq and CUT&Tag data strongly supports the existence of G4-BS conformations genome-wide. We reconstructed a novel G4-B 3D structure located in the E2F8 promoter. This study defines a large family of G4-like sequences, offering new insights into the essential biological functions and potential future therapeutic uses of G4-B.
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Affiliation(s)
- Csaba Papp
- Department of Urology, Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Vineeth T Mukundan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Piroon Jenjaroenpun
- Division of Bioinformatics and Data Management for Research, Research Group and Research Network Division, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Bioinformatics Institute, A*STAR Biomedical Institutes, Singapore, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Ghim Siong Ow
- Bioinformatics Institute, A*STAR Biomedical Institutes, Singapore, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
| | - Vladimir A Kuznetsov
- Department of Urology, Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Bioinformatics Institute, A*STAR Biomedical Institutes, Singapore, Singapore
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Shih YT, Alipio JB, Sahay A. An inhibitory circuit-based enhancer of Dyrk1a function reverses Dyrk1a -associated impairment in social recognition. bioRxiv 2023:2023.02.03.526955. [PMID: 36778241 PMCID: PMC9915696 DOI: 10.1101/2023.02.03.526955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Heterozygous mutations in the Dual specificity tyrosine-phosphorylation-regulated kinase 1a Dyrk1a gene define a syndromic form of Autism Spectrum Disorder. The synaptic and circuit mechanisms mediating Dyrk1a functions in social cognition are unclear. Here, we identify a social experience-sensitive mechanism in hippocampal mossy fiber-parvalbumin interneuron (PV IN) synapses by which Dyrk1a recruits feedforward inhibition of CA3 and CA2 to promote social recognition. We employ genetic epistasis logic to identify a cytoskeletal protein, Ablim3, as a synaptic substrate of Dyrk1a. We demonstrate that Ablim3 downregulation in dentate granule cells of adult hemizygous Dyrk1a mice is sufficient to restore PV IN mediated inhibition of CA3 and CA2 and social recognition. Acute chemogenetic activation of PV INs in CA3/CA2 of adult hemizygous Dyrk1a mice also rescued social recognition. Together, these findings illustrate how targeting Dyrk1a synaptic and circuit substrates as "enhancers of Dyrk1a function" harbors potential to reverse Dyrk1a haploinsufficiency-associated circuit and cognition impairments. Highlights Dyrk1a in mossy fibers recruits PV IN mediated feed-forward inhibition of CA3 and CA2Dyrk1a-Ablim3 signaling in mossy fiber-PV IN synapses promotes inhibition of CA3 and CA2 Downregulating Ablim3 restores PV IN excitability, CA3/CA2 inhibition and social recognition in Dyrk1a+/- mice Chemogenetic activation of PV INs in CA3/CA2 rescues social recognition in Dyrk1a+/- mice.
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Luo W, Cruz-Ochoa NA, Seng C, Egger M, Lukacsovich D, Lukacsovich T, Földy C. Pcdh11x controls target specification of mossy fiber sprouting. Front Neurosci 2022; 16:888362. [PMID: 36117624 PMCID: PMC9475199 DOI: 10.3389/fnins.2022.888362] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
Circuit formation is a defining characteristic of the developing brain. However, multiple lines of evidence suggest that circuit formation can also take place in adults, the mechanisms of which remain poorly understood. Here, we investigated the epilepsy-associated mossy fiber (MF) sprouting in the adult hippocampus and asked which cell surface molecules define its target specificity. Using single-cell RNAseq data, we found lack and expression of Pcdh11x in non-sprouting and sprouting neurons respectively. Subsequently, we used CRISPR/Cas9 genome editing to disrupt the Pcdh11x gene and characterized its consequences on sprouting. Although MF sprouting still developed, its target specificity was altered. New synapses were frequently formed on granule cell somata in addition to dendrites. Our findings shed light onto a key molecular determinant of target specificity in MF sprouting and contribute to understanding the molecular mechanism of adult brain rewiring.
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Kim J, Park D, Seo NY, Yoon TH, Kim GH, Lee SH, Seo J, Um JW, Lee KJ, Ko J. LRRTM3 regulates activity-dependent synchronization of synapse properties in topographically connected hippocampal neural circuits. Proc Natl Acad Sci U S A 2022; 119:e2110196119. [PMID: 35022233 PMCID: PMC8784129 DOI: 10.1073/pnas.2110196119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 12/03/2021] [Indexed: 11/18/2022] Open
Abstract
Synaptic cell-adhesion molecules (CAMs) organize the architecture and properties of neural circuits. However, whether synaptic CAMs are involved in activity-dependent remodeling of specific neural circuits is incompletely understood. Leucine-rich repeat transmembrane protein 3 (LRRTM3) is required for the excitatory synapse development of hippocampal dentate gyrus (DG) granule neurons. Here, we report that Lrrtm3-deficient mice exhibit selective reductions in excitatory synapse density and synaptic strength in projections involving the medial entorhinal cortex (MEC) and DG granule neurons, accompanied by increased neurotransmitter release and decreased excitability of granule neurons. LRRTM3 deletion significantly reduced excitatory synaptic innervation of hippocampal mossy fibers (Mf) of DG granule neurons onto thorny excrescences in hippocampal CA3 neurons. Moreover, LRRTM3 loss in DG neurons significantly decreased mossy fiber long-term potentiation (Mf-LTP). Remarkably, silencing MEC-DG circuits protected against the decrease in the excitatory synaptic inputs onto DG and CA3 neurons, excitability of DG granule neurons, and Mf-LTP in Lrrtm3-deficient mice. These results suggest that LRRTM3 may be a critical factor in activity-dependent synchronization of the topography of MEC-DG-CA3 excitatory synaptic connections. Collectively, our data propose that LRRTM3 shapes the target-specific structural and functional properties of specific hippocampal circuits.
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Affiliation(s)
- Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Na-Young Seo
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Neural Circuits Group, Korea Brain Research Institute (KBRI), Daegu 41062, Korea
| | - Taek-Han Yoon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Gyu Hyun Kim
- Neural Circuits Group, Korea Brain Research Institute (KBRI), Daegu 41062, Korea
| | - Sang-Hoon Lee
- Neural Circuits Group, Korea Brain Research Institute (KBRI), Daegu 41062, Korea
- Brain Research Core Facilities, KBRI, Daegu 41062, Korea
| | - Jinsoo Seo
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Kea Joo Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Neural Circuits Group, Korea Brain Research Institute (KBRI), Daegu 41062, Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
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Wang J, Vaddadi N, Pak JS, Park Y, Quilez S, Roman CA, Dumontier E, Thornton JW, Cloutier JF, Özkan E. Molecular and structural basis of olfactory sensory neuron axon coalescence by Kirrel receptors. Cell Rep 2021; 37:109940. [PMID: 34731636 PMCID: PMC8628261 DOI: 10.1016/j.celrep.2021.109940] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 07/30/2021] [Accepted: 10/13/2021] [Indexed: 01/21/2023] Open
Abstract
Projections from sensory neurons of olfactory systems coalesce into glomeruli in the brain. The Kirrel receptors are believed to homodimerize via their ectodomains and help separate sensory neuron axons into Kirrel2- or Kirrel3-expressing glomeruli. Here, we present the crystal structures of homodimeric Kirrel receptors and show that the closely related Kirrel2 and Kirrel3 have evolved specific sets of polar and hydrophobic interactions, respectively, disallowing heterodimerization while preserving homodimerization, likely resulting in proper segregation and coalescence of Kirrel-expressing axons into glomeruli. We show that the dimerization interface at the N-terminal immunoglobulin (IG) domains is necessary and sufficient to create homodimers and fail to find evidence for a secondary interaction site in Kirrel ectodomains. Furthermore, we show that abolishing dimerization of Kirrel3 in vivo leads to improper formation of glomeruli in the mouse accessory olfactory bulb as observed in Kirrel3-/- animals. Our results provide evidence for Kirrel3 homodimerization controlling axonal coalescence.
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Affiliation(s)
- Jing Wang
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA
| | - Neelima Vaddadi
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada
| | - Joseph S Pak
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA
| | - Yeonwoo Park
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Sabrina Quilez
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada
| | - Christina A Roman
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Emilie Dumontier
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada
| | - Joseph W Thornton
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA; Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
| | - Jean-François Cloutier
- The Neuro-Montreal Neurological Institute and Hospital, McGill University, Montréal, QC H3A 2B4, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 2B4, Canada; Department of Anatomy and Cell Biology, McGill University, Montréal, QC H3A 0C7, Canada.
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA; Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, The University of Chicago, Chicago, IL 60637, USA.
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13
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Hisaoka T, Komori T, Fujimoto K, Kitamura T, Morikawa Y. Comprehensive expression pattern of kin of irregular chiasm-like 3 in the adult mouse brain. Biochem Biophys Res Commun 2021; 563:66-72. [PMID: 34062388 DOI: 10.1016/j.bbrc.2021.05.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/18/2021] [Indexed: 11/16/2022]
Abstract
Kin of irregular chiasm-like 3 (Kirrel3), a member of the immunoglobulin superfamily, is expressed in the central nervous system during development and in adulthood. It has been reported that Kirrel3 is involved in the axonal fasciculation in the olfactory bulb, the neuronal migration in the pontine nucleus, and the synapse formation in the hippocampal neurons in mice. Although KIRREL3 mutations have been implicated in autism spectrum disorder and intellectual disability in humans, the comprehensive expression pattern of Kirrel3 in the adult brain is not fully understood. To better visualize Kirrel3 expression pattern and to gain insight into the role of Kirrel3 in the brain, we investigated the expression of Kirrel3 in the adult brain of Kirrel3-heterozygous (Kirrel3+/-) mice, in which Kirrel3-expressing cells could be identified by the expression of β-galactosidase (β-gal) in the nucleus of cells. The strong expression of β-gal was observed in the hippocampus, cerebral cortex, olfactory bulb, amygdala, thalamus, and cerebellum. In the hippocampus, β-gal was detected in the dentate gyrus and in the ventral parts of CA1 and CA3, which are known to be involved in the social recognition memory. Within the cerebral cortex, many cells with β-gal expression were observed in the olfactory area and auditory area. In the striatum, neurons with β-gal expression were mainly observed in the ventral striatum. Expression of β-gal was observed in all layers in the cerebellum and olfactory bulb, except for the olfactory nerve layer. Double-immunofluorescence staining of β-galactosidase with neuronal markers revealed that β-gal expression was exclusively detected in neurons. These results suggest that Kirrel3 may be involved in the maintenance of neuronal networks, such as the maintenance of synaptic connectivity and plasticity in the motor, sensory, and cognitive circuits of adult brain.
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Affiliation(s)
- Tomoko Hisaoka
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Tadasuke Komori
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Kohta Fujimoto
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Yoshihiro Morikawa
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan.
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14
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Abstract
Synaptic connectivity patterns underlie brain functions. How recognition molecules control where and when neurons form synapses with each other, therefore, is a fundamental question of cellular neuroscience. This chapter delineates adhesion and signaling complexes as well as secreted factors that contribute to synaptic partner recognition in the vertebrate brain. The sections follow a developmental perspective and discuss how recognition molecules (1) guide initial synaptic wiring, (2) provide for the rejection of incorrect partner choices, (3) contribute to synapse specification, and (4) support the removal of inappropriate synapses once formed. These processes involve a rich repertoire of molecular players and key protein families are described, notably the Cadherin and immunoglobulin superfamilies, Semaphorins/Plexins, Leucine-rich repeat containing proteins, and Neurexins and their binding partners. Molecular themes that diversify these recognition systems are defined and highlighted throughout the text, including the neuron-type specific expression and combinatorial action of recognition factors, alternative splicing, and post-translational modifications. Methodological innovations advancing the field such as proteomic approaches and single cell expression studies are additionally described. Further, the chapter highlights the importance of choosing an appropriate brain region to analyze synaptic recognition factors and the advantages offered by laminated structures like the hippocampus or retina. In a concluding section, the profound disease relevance of aberrant synaptic recognition for neurodevelopmental and psychiatric disorders is discussed. Based on the current progress, an outlook is presented on research goals that can further advance insights into how recognition molecules provide for the astounding precision and diversity of synaptic connections.
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Affiliation(s)
| | - Katherine Watters
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States; Neuroscience Graduate Program, Tufts University School of Medicine, Boston, MA, United States
| | - Thomas Biederer
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States.
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15
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Abstract
The ability to sense the world, process information, and navigate the environment depends on the assembly and continuous function of neural circuits in the brain. Within the past two decades, new technologies have rapidly advanced our understanding of how neural circuits are wired during development and how they are stably maintained, often for years. Electron microscopy reconstructions of model organism connectomes have provided a map of the stereotyped (and variable) connections in the brain; advanced light microscopy techniques have enabled direct observation of the cellular dynamics that underlie circuit construction and maintenance; transcriptomic and proteomic surveys of both developing and mature neurons have provided insights into the molecular and genetic programs governing circuit establishment and maintenance; and advanced genetic techniques have allowed for high-throughput discovery of wiring regulators. These tools have empowered scientists to rapidly generate and test hypotheses about how circuits establish and maintain connectivity. Thus, the set of principles governing circuit formation and maintenance have been expanded. These principles are discussed in this review.
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Affiliation(s)
- Emily L Heckman
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
| | - Chris Q Doe
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
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16
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Oguro-Ando A, Bamford RA, Sital W, Sprengers JJ, Zuko A, Matser JM, Oppelaar H, Sarabdjitsingh A, Joëls M, Burbach JPH, Kas MJ. Cntn4, a risk gene for neuropsychiatric disorders, modulates hippocampal synaptic plasticity and behavior. Transl Psychiatry 2021; 11:106. [PMID: 33542194 DOI: 10.1038/s41398-021-01223-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 01/05/2021] [Accepted: 01/18/2021] [Indexed: 12/27/2022] Open
Abstract
Neurodevelopmental and neuropsychiatric disorders, such as autism spectrum disorders (ASD), anorexia nervosa (AN), Alzheimer's disease (AD), and schizophrenia (SZ), are heterogeneous brain disorders with unknown etiology. Genome wide studies have revealed a wide variety of risk genes for these disorders, indicating a biological link between genetic signaling pathways and brain pathology. A unique risk gene is Contactin 4 (Cntn4), an Ig cell adhesion molecule (IgCAM) gene, which has been associated with several neuropsychiatric disorders including ASD, AN, AD, and SZ. Here, we investigated the Cntn4 gene knockout (KO) mouse model to determine whether memory dysfunction and altered brain plasticity, common neuropsychiatric symptoms, are affected by Cntn4 genetic disruption. For that purpose, we tested if Cntn4 genetic disruption affects CA1 synaptic transmission and the ability to induce LTP in hippocampal slices. Stimulation in CA1 striatum radiatum significantly decreased synaptic potentiation in slices of Cntn4 KO mice. Neuroanatomical analyses showed abnormal dendritic arborization and spines of hippocampal CA1 neurons. Short- and long-term recognition memory, spatial memory, and fear conditioning responses were also assessed. These behavioral studies showed increased contextual fear conditioning in heterozygous and homozygous KO mice, quantified by a gene-dose dependent increase in freezing response. In comparison to wild-type mice, Cntn4-deficient animals froze significantly longer and groomed more, indicative of increased stress responsiveness under these test conditions. Our electrophysiological, neuro-anatomical, and behavioral results in Cntn4 KO mice suggest that Cntn4 has important functions related to fear memory possibly in association with the neuronal morphological and synaptic plasticity changes in hippocampus CA1 neurons.
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Gandhi T, Lee CC. Neural Mechanisms Underlying Repetitive Behaviors in Rodent Models of Autism Spectrum Disorders. Front Cell Neurosci 2021; 14:592710. [PMID: 33519379 PMCID: PMC7840495 DOI: 10.3389/fncel.2020.592710] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) is comprised of several conditions characterized by alterations in social interaction, communication, and repetitive behaviors. Genetic and environmental factors contribute to the heterogeneous development of ASD behaviors. Several rodent models display ASD-like phenotypes, including repetitive behaviors. In this review article, we discuss the potential neural mechanisms involved in repetitive behaviors in rodent models of ASD and related neuropsychiatric disorders. We review signaling pathways, neural circuits, and anatomical alterations in rodent models that display robust stereotypic behaviors. Understanding the mechanisms and circuit alterations underlying repetitive behaviors in rodent models of ASD will inform translational research and provide useful insight into therapeutic strategies for the treatment of repetitive behaviors in ASD and other neuropsychiatric disorders.
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Affiliation(s)
- Tanya Gandhi
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA, United States
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18
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William N, Reissner C, Sargent R, Darlington TM, DiBlasi E, Li QS, Keeshin B, Callor WB, Ferris E, Jerominski L, Smith KR, Christensen ED, Gray DM, Camp NJ, Missler M, Williams ME, Coon H. Neurexin 1 variants as risk factors for suicide death. Mol Psychiatry 2021; 26:7436-45. [PMID: 34168285 DOI: 10.1038/s41380-021-01190-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 02/06/2023]
Abstract
Suicide is a significant public health concern with complex etiology. Although the genetic component of suicide is well established, the scope of gene networks and biological mechanisms underlying suicide has yet to be defined. Previously, we reported genome-wide evidence that neurexin 1 (NRXN1), a key synapse organizing molecule, is associated with familial suicide risk. Here we present new evidence for two non-synonymous variants (rs78540316; P469S and rs199784139; H885Y) associated with increased familial risk of suicide death. We tested the impact of these variants on binding interactions with known partners and assessed functionality in a hemi-synapse formation assay. Although the formation of hemi-synapses was not altered with the P469S variant relative to wild-type, both variants increased binding to the postsynaptic binding partner, leucine-rich repeat transmembrane neuronal 2 (LRRTM2) in vitro. Our findings indicate that variants in NRXN1 and related synaptic genes warrant further study as risk factors for suicide death.
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19
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Bahreini Jangjoo S, Lin JM, Etaati F, Fearnley S, Cloutier JF, Khmaladze A, Forni PE. Automated quantification of vomeronasal glomeruli number, size, and color composition after immunofluorescent staining. Chem Senses 2021; 46:6366009. [PMID: 34492099 PMCID: PMC8502234 DOI: 10.1093/chemse/bjab039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Glomeruli are neuropil-rich regions of the main or accessory olfactory bulbs (AOB) where the axons of olfactory or vomeronasal neurons and dendrites of mitral/tufted cells form synaptic connections. In the main olfactory system, olfactory sensory neurons (OSNs) expressing the same receptor innervate 1 or 2 glomeruli. However, in the accessory olfactory system, vomeronasal sensory neurons (VSNs) expressing the same receptor can innervate up to 30 different glomeruli in the AOB. Genetic mutation disrupting genes with a role in defining the identity/diversity of olfactory and vomeronasal neurons can alter the number and size of glomeruli. Interestingly, 2 cell surface molecules, Kirrel2 and Kirrel3, have been indicated as playing a critical role in the organization of axons into glomeruli in the AOB. Being able to quantify differences in glomeruli features, such as number, size, or immunoreactivity for specific markers, is an important experimental approach to validate the role of specific genes in controlling neuronal connectivity and circuit formation in either control or mutant animals. Since the manual recognition and quantification of glomeruli on digital images is a challenging and time-consuming task, we generated a program in Python able to identify glomeruli in digital images and quantify their properties, such as size, number, and pixel intensity. Validation of our program indicates that our script is a fast and suitable tool for high-throughput quantification of glomerular features of mouse lines with different genetic makeup.
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Affiliation(s)
| | - Jennifer M Lin
- Department of Biological Sciences, University at Albany, Albany, NY, USA.,The RNA Institute, University at Albany, Albany, NY, USA
| | - Farhood Etaati
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Sydney Fearnley
- The Neuro, 3801 University, Montréal, QC H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, QC, Canada
| | - Jean-François Cloutier
- The Neuro, 3801 University, Montréal, QC H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | | | - Paolo E Forni
- Department of Biological Sciences, University at Albany, Albany, NY, USA.,The RNA Institute, University at Albany, Albany, NY, USA
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20
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Vijayalingam S, Ezekiel UR, Xu F, Subramanian T, Geerling E, Hoelscher B, San K, Ganapathy A, Pemberton K, Tycksen E, Pinto AK, Brien JD, Beck DB, Chung WK, Gurnett CA, Chinnadurai G. Human iPSC-Derived Neuronal Cells From CTBP1-Mutated Patients Reveal Altered Expression of Neurodevelopmental Gene Networks. Front Neurosci 2020; 14:562292. [PMID: 33192249 PMCID: PMC7653094 DOI: 10.3389/fnins.2020.562292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/01/2020] [Indexed: 11/17/2022] Open
Abstract
A recurrent de novo mutation in the transcriptional corepressor CTBP1 is associated with neurodevelopmental disabilities in children (Beck et al., 2016, 2019; Sommerville et al., 2017). All reported patients harbor a single recurrent de novo heterozygous missense mutation (p.R342W) within the cofactor recruitment domain of CtBP1. To investigate the transcriptional activity of the pathogenic CTBP1 mutant allele in physiologically relevant human cell models, we generated induced pluripotent stem cells (iPSC) from the dermal fibroblasts derived from patients and normal donors. The transcriptional profiles of the iPSC-derived “early” neurons were determined by RNA-sequencing. Comparison of the RNA-seq data of the neurons from patients and normal donors revealed down regulation of gene networks involved in neurodevelopment, synaptic adhesion and anti-viral (interferon) response. Consistent with the altered gene expression patterns, the patient-derived neurons exhibited morphological and electrophysiological abnormalities, and susceptibility to viral infection. Taken together, our studies using iPSC-derived neuron models provide novel insights into the pathological activities of the CTBP1 p.R342W allele.
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Affiliation(s)
- S Vijayalingam
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Uthayashanker R Ezekiel
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Fenglian Xu
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - T Subramanian
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Elizabeth Geerling
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - Brittany Hoelscher
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - KayKay San
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Aravinda Ganapathy
- Department of Clinical Health Sciences, Doisy College of Health Science, Saint Louis University School of Medicine, Saint Louis, MO, United States
| | - Kyle Pemberton
- Department of Biology and Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, St. Louis, MO, United States
| | - Eric Tycksen
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, United States
| | - Amelia K Pinto
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - James D Brien
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
| | - David B Beck
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Wendy K Chung
- Department of Pediatrics and Medicine, Columbia University Medical Center, New York, NY, United States
| | - Christina A Gurnett
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States
| | - G Chinnadurai
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Edward A. Doisy Research Center, St. Louis, MO, United States
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21
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Apóstolo N, Smukowski SN, Vanderlinden J, Condomitti G, Rybakin V, Ten Bos J, Trobiani L, Portegies S, Vennekens KM, Gounko NV, Comoletti D, Wierda KD, Savas JN, de Wit J. Synapse type-specific proteomic dissection identifies IgSF8 as a hippocampal CA3 microcircuit organizer. Nat Commun 2020; 11:5171. [PMID: 33057002 DOI: 10.1038/s41467-020-18956-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 09/23/2020] [Indexed: 12/20/2022] Open
Abstract
Excitatory and inhibitory neurons are connected into microcircuits that generate circuit output. Central in the hippocampal CA3 microcircuit is the mossy fiber (MF) synapse, which provides powerful direct excitatory input and indirect feedforward inhibition to CA3 pyramidal neurons. Here, we dissect its cell-surface protein (CSP) composition to discover novel regulators of MF synaptic connectivity. Proteomic profiling of isolated MF synaptosomes uncovers a rich CSP composition, including many CSPs without synaptic function and several that are uncharacterized. Cell-surface interactome screening identifies IgSF8 as a neuronal receptor enriched in the MF pathway. Presynaptic Igsf8 deletion impairs MF synaptic architecture and robustly decreases the density of bouton filopodia that provide feedforward inhibition. Consequently, IgSF8 loss impairs excitation/inhibition balance and increases excitability of CA3 pyramidal neurons. Our results provide insight into the CSP landscape and interactome of a specific excitatory synapse and reveal IgSF8 as a critical regulator of CA3 microcircuit connectivity and function. Mossy fiber synapses are key in CA3 microcircuit function. Here, the authors profile the mossy fiber synapse proteome and cell-surface interactome. They uncover a diverse repertoire of cell-surface proteins and identify the receptor IgSF8 as a regulator of CA3 microcircuit connectivity and function.
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22
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Humbert J, Salian S, Makrythanasis P, Lemire G, Rousseau J, Ehresmann S, Garcia T, Alasiri R, Bottani A, Hanquinet S, Beaver E, Heeley J, Smith ACM, Berger SI, Antonarakis SE, Yang XJ, Côté J, Campeau PM. De Novo KAT5 Variants Cause a Syndrome with Recognizable Facial Dysmorphisms, Cerebellar Atrophy, Sleep Disturbance, and Epilepsy. Am J Hum Genet 2020; 107:564-574. [PMID: 32822602 PMCID: PMC7477011 DOI: 10.1016/j.ajhg.2020.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022] Open
Abstract
KAT5 encodes an essential lysine acetyltransferase, previously called TIP60, which is involved in regulating gene expression, DNA repair, chromatin remodeling, apoptosis, and cell proliferation; but it remains unclear whether variants in this gene cause a genetic disease. Here, we study three individuals with heterozygous de novo missense variants in KAT5 that affect normally invariant residues, with one at the chromodomain (p.Arg53His) and two at or near the acetyl-CoA binding site (p.Cys369Ser and p.Ser413Ala). All three individuals have cerebral malformations, seizures, global developmental delay or intellectual disability, and severe sleep disturbance. Progressive cerebellar atrophy was also noted. Histone acetylation assays with purified variant KAT5 demonstrated that the variants decrease or abolish the ability of the resulting NuA4/TIP60 multi-subunit complexes to acetylate the histone H4 tail in chromatin. Transcriptomic analysis in affected individual fibroblasts showed deregulation of multiple genes that control development. Moreover, there was also upregulated expression of PER1 (a key gene involved in circadian control) in agreement with sleep anomalies in all of the individuals. In conclusion, dominant missense KAT5 variants cause histone acetylation deficiency with transcriptional dysregulation of multiples genes, thereby leading to a neurodevelopmental syndrome with sleep disturbance, cerebellar atrophy, and facial dysmorphisms, and suggesting a recognizable syndrome.
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Affiliation(s)
- Jonathan Humbert
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du Centre Hospitalier Universitaire de Quebec-Université Laval, Quebec City, QC G1R 3S3, Canada
| | - Smrithi Salian
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Periklis Makrythanasis
- Biomedical Research Foundation of the Academy of Athens, Athens 115 27, Greece; Department of Genetic Medicine and Development, University of Geneva Medical School and Geneva University Hospitals, 1211 Geneva, Switzerland
| | - Gabrielle Lemire
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Justine Rousseau
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Sophie Ehresmann
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Thomas Garcia
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada
| | - Rami Alasiri
- Rosalind and Morris Goodman Cancer Research Centre, Department of Medicine, McGill University, Montreal, QC H3A 1A3, Canada
| | - Armand Bottani
- Service of Genetic Medicine, Geneva University Hospitals, 1211 Geneva, Switzerland
| | - Sylviane Hanquinet
- Unit of Pediatric Radiology, Geneva University Hospitals, 1211 Geneva, Switzerland
| | - Erin Beaver
- Mercy Kids Genetics, St. Louis, MO 63141, USA
| | | | - Ann C M Smith
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20894, USA
| | - Seth I Berger
- Children's National Health System, Washington, DC 20010, USA
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School and Geneva University Hospitals, 1211 Geneva, Switzerland
| | - Xiang-Jiao Yang
- Rosalind and Morris Goodman Cancer Research Centre, Department of Medicine, McGill University, Montreal, QC H3A 1A3, Canada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du Centre Hospitalier Universitaire de Quebec-Université Laval, Quebec City, QC G1R 3S3, Canada
| | - Philippe M Campeau
- Sainte-Justine Hospital Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada.
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23
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Maza FJ, Sztarker J, Cozzarin ME, Lepore MG, Delorenzi A. A crabs' high-order brain center resolved as a mushroom body-like structure. J Comp Neurol 2020; 529:501-523. [PMID: 32484921 DOI: 10.1002/cne.24960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/14/2022]
Abstract
The hypothesis of a common origin for high-order memory centers in bilateral animals presents the question of how different brain structures, such as the vertebrate hippocampus and the arthropod mushroom bodies, are both structurally and functionally comparable. Obtaining evidence to support the hypothesis that crustaceans possess structures equivalent to the mushroom bodies that play a role in associative memories has proved challenging. Structural evidence supports that the hemiellipsoid bodies of hermit crabs, crayfish and lobsters, spiny lobsters, and shrimps are homologous to insect mushroom bodies. Although a preliminary description and functional evidence supporting such homology in true crabs (Brachyura) has recently been shown, other authors consider the identification of a possible mushroom body homolog in Brachyura as problematic. Here we present morphological and immunohistochemical data in Neohelice granulata supporting that crabs possess well-developed hemiellipsoid bodies that are resolved as mushroom bodies-like structures. Neohelice exhibits a peduncle-like tract, from which processes project into proximal and distal domains with different neuronal specializations. The proximal domains exhibit spines and en passant-like processes and are proposed here as regions mainly receiving inputs. The distal domains exhibit a "trauben"-like compartmentalized structure with bulky terminal specializations and are proposed here as output regions. In addition, we found microglomeruli-like complexes, adult neurogenesis, aminergic innervation, and elevated expression of proteins necessary for memory processes. Finally, in vivo calcium imaging suggests that, as in insect mushroom bodies, the output regions exhibit stimulus-specific activity. Our results support the shared organization of memory centers across crustaceans and insects.
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Affiliation(s)
- Francisco Javier Maza
- IFIBYNE, UBA-CONICET, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
| | - Julieta Sztarker
- IFIBYNE, UBA-CONICET, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular "Profesor Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Maria Eugenia Cozzarin
- IFIBYNE, UBA-CONICET, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
| | - Maria Grazia Lepore
- IFIBYNE, UBA-CONICET, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina
| | - Alejandro Delorenzi
- IFIBYNE, UBA-CONICET, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular "Profesor Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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24
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Taylor MR, Martin EA, Sinnen B, Trilokekar R, Ranza E, Antonarakis SE, Williams ME. Kirrel3-Mediated Synapse Formation Is Attenuated by Disease-Associated Missense Variants. J Neurosci 2020; 40:5376-88. [PMID: 32503885 DOI: 10.1523/JNEUROSCI.3058-19.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/12/2022] Open
Abstract
Missense variants in Kirrel3 are repeatedly identified as risk factors for autism spectrum disorder and intellectual disability, but it has not been reported if or how these variants disrupt Kirrel3 function. Previously, we studied Kirrel3 loss of function using KO mice and showed that Kirrel3 is a synaptic adhesion molecule necessary to form one specific type of hippocampal synapse in vivo Here, we developed an in vitro, gain-of-function assay for Kirrel3 using neuron cultures prepared from male and female mice and rats. We find that WT Kirrel3 induces synapse formation selectively between Kirrel3-expressing neurons via homophilic, transcellular binding. We tested six disease-associated Kirrel3 missense variants and found that five attenuate this synaptogenic function. All variants tested traffic to the cell surface and localize to synapses similar to WT Kirrel3. Two tested variants lack homophilic transcellular binding, which likely accounts for their reduced synaptogenic function. Interestingly, we also identified variants that bind in trans but cannot induce synapses, indicating that Kirrel3 transcellular binding is necessary but not sufficient for its synaptogenic function. Collectively, these results suggest Kirrel3 functions as a synaptogenic, cell-recognition molecule, and this function is attenuated by missense variants associated with autism spectrum disorder and intellectual disability. Thus, we provide critical insight to the mechanism of Kirrel3 function and the consequences of missense variants associated with autism and intellectual disability.SIGNIFICANCE STATEMENT Here, we advance our understanding of mechanisms mediating target-specific synapse formation by providing evidence that Kirrel3 transcellular interactions mediate target recognition and signaling to promote synapse development. Moreover, this study tests the effects of disease-associated Kirrel3 missense variants on synapse formation, and thereby, increases understanding of the complex etiology of neurodevelopmental disorders arising from rare missense variants in synaptic genes.
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25
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Yang G, Shcheglovitov A. Probing disrupted neurodevelopment in autism using human stem cell-derived neurons and organoids: An outlook into future diagnostics and drug development. Dev Dyn 2019; 249:6-33. [PMID: 31398277 DOI: 10.1002/dvdy.100] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 12/11/2022] Open
Abstract
Autism spectrum disorders (ASDs) represent a spectrum of neurodevelopmental disorders characterized by impaired social interaction, repetitive or restrictive behaviors, and problems with speech. According to a recent report by the Centers for Disease Control and Prevention, one in 68 children in the US is diagnosed with ASDs. Although ASD-related diagnostics and the knowledge of ASD-associated genetic abnormalities have improved in recent years, our understanding of the cellular and molecular pathways disrupted in ASD remains very limited. As a result, no specific therapies or medications are available for individuals with ASDs. In this review, we describe the neurodevelopmental processes that are likely affected in the brains of individuals with ASDs and discuss how patient-specific stem cell-derived neurons and organoids can be used for investigating these processes at the cellular and molecular levels. Finally, we propose a discovery pipeline to be used in the future for identifying the cellular and molecular deficits and developing novel personalized therapies for individuals with idiopathic ASDs.
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Affiliation(s)
- Guang Yang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah.,Neuroscience Graduate Program, University of Utah, Salt Lake City, Utah
| | - Alex Shcheglovitov
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah.,Neuroscience Graduate Program, University of Utah, Salt Lake City, Utah
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26
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Villaseñor-Altamirano AB, Watson JD, Prokopec SD, Yao CQ, Boutros PC, Pohjanvirta R, Valdés-Flores J, Elizondo G. 2,3,7,8-Tetrachlorodibenzo-p-dioxin modifies alternative splicing in mouse liver. PLoS One 2019; 14:e0219747. [PMID: 31386671 PMCID: PMC6684058 DOI: 10.1371/journal.pone.0219747] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022] Open
Abstract
Alternative splicing is a co-transcriptional mechanism that generates protein diversity by including or excluding exons in different combinations, thereby expanding the diversity of protein isoforms of a single gene. Abnormalities in this process can result in deleterious effects to human health, and several xenobiotics are known to interfere with splicing regulation through multiple mechanisms. These changes could lead to human diseases such as cancer, neurological disorders, autoimmune diseases, and developmental disorders. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant generated as a byproduct of various industrial activities. Exposure to this dioxin has been linked to a wide range of pathologies through the alteration of multiple cellular processes. However, the effects of TCDD exposure on alternative splicing have not yet been studied. Here, we investigated whether a single po. dose of 5 μg/kg or 500 μg/kg TCDD influence hepatic alternative splicing in adult male C57BL/6Kou mouse. We identified several genes whose alternative splicing of precursor messenger RNAs was modified following TCDD exposure. In particular, we demonstrated that alternative splicing of Cyp1a1, Ahrr, and Actn1 was significantly altered after TCDD treatment. These findings show that the exposure to TCDD has an impact on alternative-splicing, and suggest a new avenue for understanding TCDD-mediated toxicity and pathogenesis.
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Affiliation(s)
- Ana B. Villaseñor-Altamirano
- Cell Biology Department, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAN-IPN, Mexico City, Mexico
- International Laboratory for Human Genome Research, National Autonomous University of Mexico, Queretaro, Mexico
| | | | | | - Cindy Q. Yao
- Ontario Institute for Cancer Research, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Paul C. Boutros
- Ontario Institute for Cancer Research, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Raimo Pohjanvirta
- Laboratory of Toxicology, National Institute for Health and Welfare, Kuopio, Finland
- Department of Food Hygiene and Environmental Health, University of Helsinki, Helsinki, Finland
| | - Jesús Valdés-Flores
- Biochemistry Department, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAV-IPN, Mexico City, Mexico
| | - Guillermo Elizondo
- Cell Biology Department, Center for Research and Advanced Studies of the National Polytechnic Institute, CINVESTAN-IPN, Mexico City, Mexico
- * E-mail:
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27
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Das SC, Chen D, Callor WB, Christensen E, Coon H, Williams ME. DiI-mediated analysis of presynaptic and postsynaptic structures in human postmortem brain tissue. J Comp Neurol 2019; 527:3087-3098. [PMID: 31152449 DOI: 10.1002/cne.24722] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/24/2019] [Accepted: 05/24/2019] [Indexed: 12/20/2022]
Abstract
Most cognitive and psychiatric disorders are thought to be disorders of the synapse, yet the precise synapse defects remain unknown. Because synapses are highly specialized anatomical structures, defects in synapse formation and function can often be observed as changes in microscale neuroanatomy. Unfortunately, few methods are available for accurate analysis of synaptic structures in human postmortem tissues. Here, we present a methodological pipeline for assessing presynaptic and postsynaptic structures in human postmortem tissue that is accurate, rapid, and relatively inexpensive. Our method uses small tissue blocks from postmortem human brains, immersion fixation, lipophilic dye (DiI) labeling, and confocal microscopy. As proof of principle, we analyzed presynaptic and postsynaptic structures from hippocampi of 13 individuals aged 4 months to 71 years. Our results indicate that postsynaptic CA1 dendritic spine shape and density do not change in adults, while presynaptic DG mossy fiber boutons undergo significant structural rearrangements with normal aging. This suggests that mossy fiber synapses, which play a major role in learning and memory, may remain dynamic throughout life. Importantly, we find that human CA1 spine densities observed using this method on tissue that is up to 28 h postmortem is comparable to prior studies using tissue with much shorter postmortem intervals. Thus, the ease of our protocol and suitability on tissue with longer postmortem intervals should facilitate higher-powered studies of human presynaptic and postsynaptic structures in healthy and diseased states.
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Affiliation(s)
- Sujan C Das
- Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, Utah
| | - Danli Chen
- Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Eric Christensen
- Utah State Office of Medical Examiner, Utah Department of Health, Salt Lake City, Utah
| | - Hilary Coon
- Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, Utah
| | - Megan E Williams
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah
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28
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Vaddadi N, Iversen K, Raja R, Phen A, Brignall A, Dumontier E, Cloutier JF. Kirrel2 is differentially required in populations of olfactory sensory neurons for the targeting of axons in the olfactory bulb. Development 2019; 146:dev.173310. [PMID: 31142543 DOI: 10.1242/dev.173310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 05/15/2019] [Indexed: 01/25/2023]
Abstract
The formation of olfactory maps in the olfactory bulb (OB) is crucial for the control of innate and learned mouse behaviors. Olfactory sensory neurons (OSNs) expressing a specific odorant receptor project axons into spatially conserved glomeruli within the OB and synapse onto mitral cell dendrites. Combinatorial expression of members of the Kirrel family of cell adhesion molecules has been proposed to regulate OSN axonal coalescence; however, loss-of-function experiments have yet to establish their requirement in this process. We examined projections of several OSN populations in mice that lacked either Kirrel2 alone, or both Kirrel2 and Kirrel3. Our results show that Kirrel2 and Kirrel3 are dispensable for the coalescence of MOR1-3-expressing OSN axons to the most dorsal region (DI) of the OB. In contrast, loss of Kirrel2 caused MOR174-9- and M72-expressing OSN axons, projecting to the DII region, to target ectopic glomeruli. Our loss-of-function approach demonstrates that Kirrel2 is required for axonal coalescence in subsets of OSNs that project axons to the DII region and reveals that Kirrel2/3-independent mechanisms also control OSN axonal coalescence in certain regions of the OB.
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Affiliation(s)
- Neelima Vaddadi
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Katrine Iversen
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Reesha Raja
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Alina Phen
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Alexandra Brignall
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Emilie Dumontier
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada
| | - Jean-François Cloutier
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada .,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
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29
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Hatcher C, Relton CL, Gaunt TR, Richardson TG. Leveraging brain cortex-derived molecular data to elucidate epigenetic and transcriptomic drivers of complex traits and disease. Transl Psychiatry 2019; 9:105. [PMID: 30820025 PMCID: PMC6395652 DOI: 10.1038/s41398-019-0437-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 12/23/2022] Open
Abstract
Integrative approaches that harness large-scale molecular datasets can help develop mechanistic insight into findings from genome-wide association studies (GWAS). We have performed extensive analyses to uncover transcriptional and epigenetic processes which may play a role in complex trait variation. This was undertaken by applying Bayesian multiple-trait colocalization systematically across the genome to identify genetic variants responsible for influencing intermediate molecular phenotypes as well as complex traits. In this analysis, we leveraged high-dimensional quantitative trait loci data derived from the prefrontal cortex tissue (concerning gene expression, DNA methylation and histone acetylation) and GWAS findings for five complex traits (Neuroticism, Schizophrenia, Educational Attainment, Insomnia and Alzheimer's disease). There was evidence of colocalization for 118 associations, suggesting that the same underlying genetic variant influenced both nearby gene expression as well as complex trait variation. Of these, 73 associations provided evidence that the genetic variant also influenced proximal DNA methylation and/or histone acetylation. These findings support previous evidence at loci where epigenetic mechanisms may putatively mediate effects of genetic variants on traits, such as KLC1 and schizophrenia. We also uncovered evidence implicating novel loci in disease susceptibility, including genes expressed predominantly in the brain tissue, such as MDGA1, KIRREL3 and SLC12A5. An inverse relationship between DNA methylation and gene expression was observed more than can be accounted for by chance, supporting previous findings implicating DNA methylation as a transcriptional repressor. Our study should prove valuable in helping future studies prioritize candidate genes and epigenetic mechanisms for in-depth functional follow-up analyses.
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Affiliation(s)
- Charlie Hatcher
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Caroline L Relton
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Tom R Gaunt
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Tom G Richardson
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
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30
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Leblond CS, Cliquet F, Carton C, Huguet G, Mathieu A, Kergrohen T, Buratti J, Lemière N, Cuisset L, Bienvenu T, Boland A, Deleuze JF, Stora T, Biskupstoe R, Halling J, Andorsdóttir G, Billstedt E, Gillberg C, Bourgeron T. Both rare and common genetic variants contribute to autism in the Faroe Islands. NPJ Genom Med 2019; 4:1. [PMID: 30675382 DOI: 10.1038/s41525-018-0075-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/13/2018] [Indexed: 11/09/2022] Open
Abstract
The number of genes associated with autism is increasing, but few studies have been performed on epidemiological cohorts and in isolated populations. Here, we investigated 357 individuals from the Faroe Islands including 36 individuals with autism, 136 of their relatives and 185 non-autism controls. Data from SNP array and whole exome sequencing revealed that individuals with autism had a higher burden of rare exonic copy-number variants altering autism associated genes (deletions (p = 0.0352) or duplications (p = 0.0352)), higher inbreeding status (p = 0.023) and a higher load of rare homozygous deleterious variants (p = 0.011) compared to controls. Our analysis supports the role of several genes/loci associated with autism (e.g., NRXN1, ADNP, 22q11 deletion) and identified new truncating (e.g., GRIK2, ROBO1, NINL, and IMMP2L) or recessive deleterious variants (e.g., KIRREL3 and CNTNAP2) affecting autism-associated genes. It also revealed three genes involved in synaptic plasticity, RIMS4, KALRN, and PLA2G4A, carrying de novo deleterious variants in individuals with autism without intellectual disability. In summary, our analysis provides a better understanding of the genetic architecture of autism in isolated populations by highlighting the role of both common and rare gene variants and pointing at new autism-risk genes. It also indicates that more knowledge about how multiple genetic hits affect neuronal function will be necessary to fully understand the genetic architecture of autism.
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31
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Cijsouw T, Ramsey AM, Lam TT, Carbone BE, Blanpied TA, Biederer T. Mapping the Proteome of the Synaptic Cleft through Proximity Labeling Reveals New Cleft Proteins. Proteomes 2018; 6:proteomes6040048. [PMID: 30487426 PMCID: PMC6313906 DOI: 10.3390/proteomes6040048] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/15/2018] [Accepted: 11/18/2018] [Indexed: 12/21/2022] Open
Abstract
Synapses are specialized neuronal cell-cell contacts that underlie network communication in the mammalian brain. Across neuronal populations and circuits, a diverse set of synapses is utilized, and they differ in their molecular composition to enable heterogenous connectivity patterns and functions. In addition to pre- and post-synaptic specializations, the synaptic cleft is now understood to be an integral compartment of synapses that contributes to their structural and functional organization. Aiming to map the cleft proteome, this study applied a peroxidase-mediated proximity labeling approach and used the excitatory synaptic cell adhesion protein SynCAM 1 fused to horseradish peroxidase (HRP) as a reporter in cultured cortical neurons. This reporter marked excitatory synapses as measured by confocal microcopy and was targeted to the edge zone of the synaptic cleft as determined using 3D dSTORM super-resolution imaging. Proximity labeling with a membrane-impermeant biotin-phenol compound restricted labeling to the cell surface, and Label-Free Quantitation (LFQ) mass spectrometry combined with ratiometric HRP tagging of membrane vs. synaptic surface proteins was used to identify the proteomic content of excitatory clefts. Novel cleft candidates were identified, and Receptor-type tyrosine-protein phosphatase zeta was selected and successfully validated. This study supports the robust applicability of peroxidase-mediated proximity labeling for synaptic cleft proteomics and its potential for understanding synapse heterogeneity in health and changes in diseases such as psychiatric disorders and addiction.
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Affiliation(s)
- Tony Cijsouw
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Austin M Ramsey
- Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - TuKiet T Lam
- Yale/NIDA Neuroproteomics Center, New Haven, CT 06511, USA.
- W.M. Keck Biotechnology Resource Laboratory, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Beatrice E Carbone
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Thomas A Blanpied
- Department of Physiology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
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32
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Völker LA, Maar BA, Pulido Guevara BA, Bilkei-Gorzo A, Zimmer A, Brönneke H, Dafinger C, Bertsch S, Wagener JR, Schweizer H, Schermer B, Benzing T, Hoehne M. Neph2/Kirrel3 regulates sensory input, motor coordination, and home-cage activity in rodents. Genes, Brain and Behavior 2018; 17:e12516. [DOI: 10.1111/gbb.12516] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 07/22/2018] [Accepted: 08/17/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Linus A. Völker
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
| | - Barbara A. Maar
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
| | - Barbara A. Pulido Guevara
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
| | - Andras Bilkei-Gorzo
- Institute of Molecular Psychiatry; Medical Faculty of the University of Bonn; Bonn Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry; Medical Faculty of the University of Bonn; Bonn Germany
| | - Hella Brönneke
- Mouse Phenotyping Core Facility; Cologne Excellence Cluster on Cellular Stress Responses (CECAD); 50931 Cologne Germany
| | - Claudia Dafinger
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
| | - Sabine Bertsch
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
| | - Jan-Robin Wagener
- Institute for Neuroanatomy, Universitätsmedizin Göttingen; Georg-August-University Göttingen; Göttingen Germany
| | - Heiko Schweizer
- Renal Division; University Hospital Freiburg; Freiburg Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD); University of Cologne; Cologne Germany
- Systems Biology of Ageing Cologne (Sybacol); University of Cologne; Cologne Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD); University of Cologne; Cologne Germany
- Systems Biology of Ageing Cologne (Sybacol); University of Cologne; Cologne Germany
| | - Martin Hoehne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne; University of Cologne; Cologne Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD); University of Cologne; Cologne Germany
- Systems Biology of Ageing Cologne (Sybacol); University of Cologne; Cologne Germany
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33
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Park D, Bae S, Yoon TH, Ko J. Molecular Mechanisms of Synaptic Specificity: Spotlight on Hippocampal and Cerebellar Synapse Organizers. Mol Cells 2018; 41:373-380. [PMID: 29665671 PMCID: PMC5974614 DOI: 10.14348/molcells.2018.0081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 03/30/2018] [Accepted: 04/02/2018] [Indexed: 12/13/2022] Open
Abstract
Synapses and neural circuits form with exquisite specificity during brain development to allow the precise and appropriate flow of neural information. Although this property of synapses and neural circuits has been extensively investigated for more than a century, molecular mechanisms underlying this property are only recently being unveiled. Recent studies highlight several classes of cell-surface proteins as organizing hubs in building structural and functional architectures of specific synapses and neural circuits. In the present mini-review, we discuss recent findings on various synapse organizers that confer the distinct properties of specific synapse types and neural circuit architectures in mammalian brains, with a particular focus on the hippocampus and cerebellum.
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Affiliation(s)
- Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Sungwon Bae
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Taek Han Yoon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988,
Korea
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34
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Guo N, Soden ME, Herber C, Kim MT, Besnard A, Lin P, Ma X, Cepko CL, Zweifel LS, Sahay A. Dentate granule cell recruitment of feedforward inhibition governs engram maintenance and remote memory generalization. Nat Med 2018. [PMID: 29529016 PMCID: PMC5893385 DOI: 10.1038/nm.4491] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Memories become less precise and generalize over time as memory traces re-organize in hippocampal-cortical networks. Increased time-dependent loss of memory precision characterizes overgeneralization of fear in post-traumatic stress disorder (PTSD) and age-related cognitive impairments. In the hippocampal dentate gyrus (DG), memories are thought to be encoded by so-called “engram-bearing” dentate granule cells (eDGCs). Here we show using rodents that contextual fear conditioning increases connectivity between eDGCs and inhibitory interneurons in the downstream hippocampal CA3 region. We identify actin-binding LIM protein 3 (abLIM3) as a mossy fiber terminal localized cytoskeletal factor, whose levels decrease upon learning. Downregulation of abLIM3 in DGCs was sufficient to increase connectivity with CA3 stratum lucidum interneurons (SLINs), promote parvalbumin (PV) SLIN activation, enhance feed-forward inhibition onto CA3, and maintain a fear memory engram in the dentate gyrus (DG) over time. Furthermore, abLIM3 downregulation in DGCs conferred conditioned context-specific reactivation of memory traces in hippocampal-cortical and amygdalar networks and decreased fear memory generalization at remote time points. Consistent with age-related hyperactivity of CA3, learning failed to increase DGC-SLIN connectivity in 17 month-old mice, whereas abLIM3 downregulation was sufficient to restore DGC-SLIN connectivity, increase PV-SLIN activation and improve remote memory precision. These studies exemplify a connectivity-based strategy targeting a molecular brake of feedforward inhibition in DG-CA3 that may be harnessed to decrease time-dependent memory generalization in PTSD and improve memory precision in aging.
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Affiliation(s)
- Nannan Guo
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marta E Soden
- Department of Pharmacology, University of Washington, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - Charlotte Herber
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Michael TaeWoo Kim
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Antoine Besnard
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Paoyan Lin
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Xiang Ma
- Howard Hughes Medical Institute, Boston, Massachusetts, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Constance L Cepko
- Howard Hughes Medical Institute, Boston, Massachusetts, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Larry S Zweifel
- Department of Pharmacology, University of Washington, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital (MGH), Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.,BROAD Institute of Harvard and Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, USA
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35
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Hisaoka T, Komori T, Kitamura T, Morikawa Y. Abnormal behaviours relevant to neurodevelopmental disorders in Kirrel3-knockout mice. Sci Rep 2018; 8:1408. [PMID: 29362445 PMCID: PMC5780462 DOI: 10.1038/s41598-018-19844-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/09/2018] [Indexed: 12/21/2022] Open
Abstract
In the nervous system, Kirrel3 is involved in neuronal migration, axonal fasciculation, and synapse formation. Recently, genetic links have been reported between mutations in the KIRREL3 gene and increased risk of neurodevelopmental disorders, including autism spectrum disorder (ASD) and intellectual disability. To elucidate the causal relationship between KIRREL3 deficiency and behavioural abnormalities relevant to neurodevelopmental disorders, we generated global Kirrel3-knockout (Kirrel3−/−) mice and investigated the detailed behavioural phenotypes. In the three-chambered social approach test, Kirrel3−/− mice displayed a significant preference for a mouse over a non-social object but no significant preference for a stranger mouse over a familiar mouse. Ultrasonic communications, including pup-to-mother calls, male-female courtship vocalisation and resident responses to intruder, were significantly impaired in Kirrel3−/− mice. Significant increases in locomotor activity and repetitive rearing were also observed in Kirrel3−/− mice. Furthermore, the performance of Kirrel3−/− mice in the rotarod test was significantly better than that of wild-type mice. In the acoustic startle test, Kirrel3−/− mice were significantly hypersensitive to acoustic stimuli. Anxiety-related behaviours and spatial or fear memory acquisition were normal in Kirrel3−/− mice. These findings suggest that Kirrel3−/− mice exhibit autistic-like behaviours, including social and communicative deficits, repetitive behaviours, and sensory abnormalities, as well as hyperactivity.
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Affiliation(s)
- Tomoko Hisaoka
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Tadasuke Komori
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Yoshihiro Morikawa
- Department of Anatomy and Neurobiology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan.
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36
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Basu R, Duan X, Taylor MR, Martin EA, Muralidhar S, Wang Y, Gangi-Wellman L, Das SC, Yamagata M, West PJ, Sanes JR, Williams ME. Heterophilic Type II Cadherins Are Required for High-Magnitude Synaptic Potentiation in the Hippocampus. Neuron 2017; 96:160-176.e8. [PMID: 28957665 DOI: 10.1016/j.neuron.2017.09.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 08/03/2017] [Accepted: 09/11/2017] [Indexed: 11/26/2022]
Abstract
Hippocampal CA3 neurons form synapses with CA1 neurons in two layers, stratum oriens (SO) and stratum radiatum (SR). Each layer develops unique synaptic properties but molecular mechanisms that mediate these differences are unknown. Here, we show that SO synapses normally have significantly more mushroom spines and higher-magnitude long-term potentiation (LTP) than SR synapses. Further, we discovered that these differences require the Type II classic cadherins, cadherins-6, -9, and -10. Though cadherins typically function via trans-cellular homophilic interactions, our results suggest presynaptic cadherin-9 binds postsynaptic cadherins-6 and -10 to regulate mushroom spine density and high-magnitude LTP in the SO layer. Loss of these cadherins has no effect on the lower-magnitude LTP typically observed in the SR layer, demonstrating that cadherins-6, -9, and -10 are gatekeepers for high-magnitude LTP. Thus, Type II cadherins may uniquely contribute to the specificity and strength of synaptic changes associated with learning and memory.
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Affiliation(s)
- Raunak Basu
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Xin Duan
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA 94117, USA
| | - Matthew R Taylor
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - E Anne Martin
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Shruti Muralidhar
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Yueqi Wang
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Luke Gangi-Wellman
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Sujan C Das
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Masahito Yamagata
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Peter J West
- Department of Pharmacology and Toxicology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Megan E Williams
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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37
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Brignall AC, Raja R, Phen A, Prince JEA, Dumontier E, Cloutier J. Loss of Kirrel family members alters glomerular structure and synapse numbers in the accessory olfactory bulb. Brain Struct Funct 2018; 223:307-19. [DOI: 10.1007/s00429-017-1485-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
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38
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Martin EA, Woodruff D, Rawson RL, Williams ME. Examining Hippocampal Mossy Fiber Synapses by 3D Electron Microscopy in Wildtype and Kirrel3 Knockout Mice. eNeuro 2017; 4:ENEURO. [PMID: 28670619 DOI: 10.1523/ENEURO.0088-17.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 04/20/2017] [Accepted: 05/17/2017] [Indexed: 11/27/2022] Open
Abstract
Neural circuits balance excitatory and inhibitory activity and disruptions in this balance are commonly found in neurodevelopmental disorders. Mice lacking the intellectual disability and autism-associated gene Kirrel3 have an excitation-inhibition imbalance in the hippocampus but the precise synaptic changes underlying this functional defect are unknown. Kirrel3 is a homophilic adhesion molecule expressed in dentate gyrus (DG) and GABA neurons. It was suggested that the excitation-inhibition imbalance of hippocampal neurons in Kirrel3 knockout mice is due to loss of mossy fiber (MF) filopodia, which are DG axon protrusions thought to excite GABA neurons and thereby provide feed-forward inhibition to CA3 pyramidal neurons. Fewer filopodial structures were observed in Kirrel3 knockout mice but neither filopodial synapses nor DG en passant synapses, which also excite GABA neurons, were examined. Here, we used serial block-face scanning electron microscopy (SBEM) with 3D reconstruction to define the precise connectivity of MF filopodia and elucidate synaptic changes induced by Kirrel3 loss. Surprisingly, we discovered wildtype MF filopodia do not synapse exclusively onto GABA neurons as previously thought, but instead synapse with similar frequency onto GABA neurons and CA3 neurons. Moreover, Kirrel3 loss selectively reduces MF filopodial synapses onto GABA neurons but not those made onto CA3 neurons or en passant synapses. In sum, the selective loss of MF filopodial synapses with GABA neurons likely underlies the hippocampal activity imbalance observed in Kirrel3 knockout mice and may impact neural function in patients with Kirrel3-dependent neurodevelopmental disorders.
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39
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Sakurai T. The role of cell adhesion molecules in brain wiring and neuropsychiatric disorders. Mol Cell Neurosci 2017; 81:4-11. [PMID: 27561442 DOI: 10.1016/j.mcn.2016.08.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/16/2016] [Accepted: 08/19/2016] [Indexed: 12/15/2022] Open
Abstract
Cell adhesion molecules (CAMs) in the nervous system have long been a research focus, but many mice lacking CAMs show very subtle phenotypes, giving an impression that CAMs may not be major players in constructing the nervous system. However, recent human genetic studies suggest CAM involvement in many neuropsychiatric disorders, implicating that they must have significant functions in nervous system development, namely in circuitry formation. As CAMs can provide specificity through their molecular interactions, this review summarizes possible mechanisms on how alterations of CAMs can result in neuropsychiatric disorders through circuitry modification.
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Affiliation(s)
- Takeshi Sakurai
- Medical Innovation Center, Kyoto University Graduate School of Medicine, 53 Shogoin Kawaharacho, Sakyo-ku, Kyoto, 606-8507, Japan.
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40
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Bibollet-Bahena O, Okafuji T, Hokamp K, Tear G, Mitchell KJ. A dual-strategy expression screen for candidate connectivity labels in the developing thalamus. PLoS One 2017; 12:e0177977. [PMID: 28558017 PMCID: PMC5448750 DOI: 10.1371/journal.pone.0177977] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 05/05/2017] [Indexed: 12/13/2022] Open
Abstract
The thalamus or “inner chamber” of the brain is divided into ~30 discrete nuclei, with highly specific patterns of afferent and efferent connectivity. To identify genes that may direct these patterns of connectivity, we used two strategies. First, we used a bioinformatics pipeline to survey the predicted proteomes of nematode, fruitfly, mouse and human for extracellular proteins containing any of a list of motifs found in known guidance or connectivity molecules. Second, we performed clustering analyses on the Allen Developing Mouse Brain Atlas data to identify genes encoding surface proteins expressed with temporal profiles similar to known guidance or connectivity molecules. In both cases, we then screened the resultant genes for selective expression patterns in the developing thalamus. These approaches identified 82 candidate connectivity labels in the developing thalamus. These molecules include many members of the Ephrin, Eph-receptor, cadherin, protocadherin, semaphorin, plexin, Odz/teneurin, Neto, cerebellin, calsyntenin and Netrin-G families, as well as diverse members of the immunoglobulin (Ig) and leucine-rich receptor (LRR) superfamilies, receptor tyrosine kinases and phosphatases, a variety of growth factors and receptors, and a large number of miscellaneous membrane-associated or secreted proteins not previously implicated in axonal guidance or neuronal connectivity. The diversity of their expression patterns indicates that thalamic nuclei are highly differentiated from each other, with each one displaying a unique repertoire of these molecules, consistent with a combinatorial logic to the specification of thalamic connectivity.
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Affiliation(s)
| | - Tatsuya Okafuji
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Karsten Hokamp
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Guy Tear
- Department of Developmental Neurobiology, New Hunt’s House, Guy’s Campus, King’s College, London, United Kingdom
| | - Kevin J. Mitchell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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41
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Rawson RL, Martin EA, Williams ME. Mechanisms of input and output synaptic specificity: finding partners, building synapses, and fine-tuning communication. Curr Opin Neurobiol 2017; 45:39-44. [PMID: 28388510 DOI: 10.1016/j.conb.2017.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/16/2017] [Indexed: 12/12/2022]
Abstract
For most neurons to function properly, they need to develop synaptic specificity. This requires finding specific partner neurons, building the correct types of synapses, and fine-tuning these synapses in response to neural activity. Synaptic specificity is common at both a neuron's input and output synapses, whereby unique synapses are built depending on the partnering neuron. Neuroscientists have long appreciated the remarkable specificity of neural circuits but identifying molecular mechanisms mediating synaptic specificity has only recently accelerated. Here, we focus on recent progress in understanding input and output synaptic specificity in the mammalian brain. We review newly identified circuit examples for both and the latest research identifying molecular mediators including Kirrel3, FGFs, and DGLα. Lastly, we expect the pace of research on input and output specificity to continue to accelerate with the advent of new technologies in genomics, microscopy, and proteomics.
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Affiliation(s)
- Randi L Rawson
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, 20 South 2030 East, Salt Lake City, UT 84112, United States
| | - E Anne Martin
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, 20 South 2030 East, Salt Lake City, UT 84112, United States
| | - Megan E Williams
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, 20 South 2030 East, Salt Lake City, UT 84112, United States.
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42
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Roh JD, Choi SY, Cho YS, Choi TY, Park JS, Cutforth T, Chung W, Park H, Lee D, Kim MH, Lee Y, Mo S, Rhee JS, Kim H, Ko J, Choi SY, Bae YC, Shen K, Kim E, Han K. Increased Excitatory Synaptic Transmission of Dentate Granule Neurons in Mice Lacking PSD-95-Interacting Adhesion Molecule Neph2/Kirrel3 during the Early Postnatal Period. Front Mol Neurosci 2017; 10:81. [PMID: 28381988 PMCID: PMC5360738 DOI: 10.3389/fnmol.2017.00081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 03/08/2017] [Indexed: 11/13/2022] Open
Abstract
Copy number variants and point mutations of NEPH2 (also called KIRREL3) gene encoding an immunoglobulin (Ig) superfamily adhesion molecule have been linked to autism spectrum disorders, intellectual disability and neurocognitive delay associated with Jacobsen syndrome, but the physiological roles of Neph2 in the mammalian brain remain largely unknown. Neph2 is highly expressed in the dentate granule (DG) neurons of the hippocampus and is localized in both dendrites and axons. It was recently shown that Neph2 is required for the formation of mossy fiber filopodia, the axon terminal structure of DG neurons forming synapses with GABAergic neurons of CA3. In contrast, however, it is unknown whether Neph2 also has any roles in the postsynaptic compartments of DG neurons. We here report that, through its C-terminal PDZ domain-binding motif, Neph2 directly interacts with postsynaptic density (PSD)-95, an abundant excitatory postsynaptic scaffolding protein. Moreover, Neph2 protein is detected in the brain PSD fraction and interacts with PSD-95 in synaptosomal lysates. Functionally, loss of Neph2 in mice leads to age-specific defects in the synaptic connectivity of DG neurons. Specifically, Neph2-/- mice show significantly increased spontaneous excitatory synaptic events in DG neurons at postnatal week 2 when the endogenous Neph2 protein expression peaks, but show normal excitatory synaptic transmission at postnatal week 3. The evoked excitatory synaptic transmission and synaptic plasticity of medial perforant pathway (MPP)-DG synapses are also normal in Neph2-/- mice at postnatal week 3, further confirming the age-specific synaptic defects. Together, our results provide some evidence for the postsynaptic function of Neph2 in DG neurons during the early postnatal period, which might be implicated in neurodevelopmental and cognitive disorders caused by NEPH2 mutations.
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Affiliation(s)
- Junyeop D Roh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST) Daejeon, South Korea
| | - Su-Yeon Choi
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS) Daejeon, South Korea
| | - Yi Sul Cho
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Daegu, South Korea
| | - Tae-Yong Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry Seoul, South Korea
| | - Jong-Sil Park
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry Seoul, South Korea
| | - Tyler Cutforth
- Department of Neurology, Columbia University Medical Center New York, NY, USA
| | - Woosuk Chung
- Department of Anesthesiology and Pain Medicine, College of Medicine, Chungnam National University Daejeon, South Korea
| | - Hanwool Park
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS) Daejeon, South Korea
| | - Dongsoo Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS) Daejeon, South Korea
| | - Myeong-Heui Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST) Daejeon, South Korea
| | - Yeunkum Lee
- Department of Neuroscience, College of Medicine, Korea University Seoul, South Korea
| | - Seojung Mo
- Department of Anatomy, College of Medicine, Korea University Seoul, South Korea
| | - Jeong-Seop Rhee
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine Göttingen, Germany
| | - Hyun Kim
- Department of Anatomy, College of Medicine, Korea University Seoul, South Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu, South Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry Seoul, South Korea
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Daegu, South Korea
| | - Kang Shen
- Department of Biology, Howard Hughes Medical Institute, Stanford University Stanford, CA, USA
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST)Daejeon, South Korea; Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS)Daejeon, South Korea
| | - Kihoon Han
- Department of Neuroscience, College of Medicine, Korea University Seoul, South Korea
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Arnold N, Meyer C, Engelmann F, Messaoudi I. Robust gene expression changes in the ganglia following subclinical reactivation in rhesus macaques infected with simian varicella virus. J Neurovirol 2017; 23:520-38. [PMID: 28321697 DOI: 10.1007/s13365-017-0522-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/03/2017] [Accepted: 02/17/2017] [Indexed: 12/20/2022]
Abstract
Varicella zoster virus (VZV) causes varicella during acute infection and establishes latency in the sensory ganglia. Reactivation of VZV results in herpes zoster, a debilitating and painful disease. It is believed that VZV reactivates due to a decline in cell-mediated immunity; however, the roles that CD4 versus CD8 T cells play in the prevention of herpes zoster remain poorly understood. To address this question, we used a well-characterized model of VZV infection where rhesus macaques are intrabronchially infected with the homologous simian varicella virus (SVV). Latently infected rhesus macaques were thymectomized and depleted of either CD4 or CD8 T cells to induce selective senescence of each T cell subset. After T cell depletion, the animals were transferred to a new housing room to induce stress. SVV reactivation (viremia in the absence of rash) was detected in three out of six CD8-depleted and two out of six CD4-depleted animals suggesting that both CD4 and CD8 T cells play a critical role in preventing SVV reactivation. Viral loads in multiple ganglia were higher in reactivated animals compared to non-reactivated animals. In addition, reactivation results in sustained transcriptional changes in the ganglia that enriched to gene ontology and diseases terms associated with neuronal function and inflammation indicative of potential damage as a result of viral reactivation. These studies support the critical role of cellular immunity in preventing varicella virus reactivation and indicate that reactivation results in long-lasting remodeling of the ganglia transcriptome.
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Baig DN, Yanagawa T, Tabuchi K. Distortion of the normal function of synaptic cell adhesion molecules by genetic variants as a risk for autism spectrum disorders. Brain Res Bull 2016; 129:82-90. [PMID: 27743928 DOI: 10.1016/j.brainresbull.2016.10.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/08/2016] [Accepted: 10/10/2016] [Indexed: 12/15/2022]
Abstract
Synaptic cell adhesion molecules (SCAMs) are a functional category of cell adhesion molecules that connect pre- and postsynapses by the protein-protein interaction via their extracellular cell adhesion domains. Countless numbers of common genetic variants and rare mutations in SCAMs have been identified in the patients with autism spectrum disorders (ASDs). Among these, NRXN and NLGN family proteins cooperatively function at synaptic terminals both of which genes are strongly implicated as risk genes for ASDs. Knock-in mice carrying a single rare point mutation of NLGN3 (NLGN3 R451C) discovered in the patients with ASDs display a deficit in social interaction and an enhancement of spatial learning and memory ability reminiscent of the clinical phenotype of ASDs. NLGN4 knockout (KO) and NRXN2α KO mice also show a deficit in sociability as well as some specific neuropsychiatric behaviors. In this review, we selected NRXNs/NLGNs, CNTNAP2/CNTNAP4, CNTN4, ITGB3, and KIRREL3 as strong ASD risk genes based on SFARI score and summarize the protein structures, functions at synapses, representative discoveries in human genetic studies, and phenotypes of the mutant model mice in light of the pathophysiology of ASDs.
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Affiliation(s)
- Deeba Noreen Baig
- Department of Biological Sciences, Forman Christian College, Zahoor Elahi Rd, Lahore, 54600, Pakistan
| | - Toru Yanagawa
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Ibaraki, 305-8575, Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto, 390-8621, Japan; PRESTO, JST, Saitama, 332-0012, Japan.
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45
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Park KA, Ribic A, Laage Gaupp FM, Coman D, Huang Y, Dulla CG, Hyder F, Biederer T. Excitatory Synaptic Drive and Feedforward Inhibition in the Hippocampal CA3 Circuit Are Regulated by SynCAM 1. J Neurosci 2016; 36:7464-75. [PMID: 27413156 PMCID: PMC4945666 DOI: 10.1523/jneurosci.0189-16.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/24/2023] Open
Abstract
UNLABELLED Select adhesion proteins control the development of synapses and modulate their structural and functional properties. Despite these important roles, the extent to which different synapse-organizing mechanisms act across brain regions to establish connectivity and regulate network properties is incompletely understood. Further, their functional roles in different neuronal populations remain to be defined. Here, we applied diffusion tensor imaging (DTI), a modality of magnetic resonance imaging (MRI), to map connectivity changes in knock-out (KO) mice lacking the synaptogenic cell adhesion protein SynCAM 1. This identified reduced fractional anisotropy in the hippocampal CA3 area in absence of SynCAM 1. In agreement, mossy fiber refinement in CA3 was impaired in SynCAM 1 KO mice. Mossy fibers make excitatory inputs onto postsynaptic specializations of CA3 pyramidal neurons termed thorny excrescences and these structures were smaller in the absence of SynCAM 1. However, the most prevalent targets of mossy fibers are GABAergic interneurons and SynCAM 1 loss unexpectedly reduced the number of excitatory terminals onto parvalbumin (PV)-positive interneurons in CA3. SynCAM 1 KO mice additionally exhibited lower postsynaptic GluA1 expression in these PV-positive interneurons. These synaptic imbalances in SynCAM 1 KO mice resulted in CA3 disinhibition, in agreement with reduced feedforward inhibition in this network in the absence of SynCAM 1-dependent excitatory drive onto interneurons. In turn, mice lacking SynCAM 1 were impaired in memory tasks involving CA3. Our results support that SynCAM 1 modulates excitatory mossy fiber inputs onto both interneurons and principal neurons in the hippocampal CA3 area to balance network excitability. SIGNIFICANCE STATEMENT This study advances our understanding of synapse-organizing mechanisms on two levels. First, the data support that synaptogenic proteins guide connectivity and can function in distinct brain regions even if they are expressed broadly. Second, the results demonstrate that a synaptogenic process that controls excitatory inputs to both pyramidal neurons and interneurons can balance excitation and inhibition. Specifically, the study reveals that hippocampal CA3 connectivity is modulated by the synapse-organizing adhesion protein SynCAM 1 and identifies a novel, SynCAM 1-dependent mechanism that controls excitatory inputs onto parvalbumin-positive interneurons. This enables SynCAM 1 to regulate feedforward inhibition and set network excitability. Further, we show that diffusion tensor imaging is sensitive to these cellular refinements affecting neuronal connectivity.
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Affiliation(s)
- Kellie A Park
- Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Adema Ribic
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Fabian M Laage Gaupp
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians-University, 80539 Munich, Germany
| | - Daniel Coman
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut 06520, and
| | - Yuegao Huang
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut 06520, and
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Fahmeed Hyder
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut 06520, and Department of Biomedical Engineering, Yale University, School of Engineering and Applied Science, New Haven, Connecticut 06520
| | - Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111,
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