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Ash RT, Park J, Suter B, Zoghbi HY, Smirnakis SM. Excessive Formation and Stabilization of Dendritic Spine Clusters in the MECP2-Duplication Syndrome Mouse Model of Autism. eNeuro 2021; 8:ENEURO.0282-20.2020. [PMID: 33168618 PMCID: PMC7877475 DOI: 10.1523/eneuro.0282-20.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/11/2020] [Accepted: 09/14/2020] [Indexed: 11/21/2022] Open
Abstract
Autism-associated genetic mutations may perturb the balance between stability and plasticity of synaptic connections in the brain. Here, we report an increase in the formation and stabilization of dendritic spines in the cerebral cortex of the mouse model of MECP2-duplication syndrome, a high-penetrance form of syndromic autism. Increased stabilization is mediated entirely by spines that form cooperatively in 10-μm clusters and is observable across multiple cortical areas both spontaneously and following motor training. Excessive stability of dendritic spine clusters could contribute to behavioral rigidity and other phenotypes in syndromic autism.
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Affiliation(s)
- Ryan Thomas Ash
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Jiyoung Park
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Bernhard Suter
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
- Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine, Houston, TX 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
| | - Huda Yaya Zoghbi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine, Houston, TX 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030
| | - Stelios Manolis Smirnakis
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
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Briševac D, Scholz R, Du D, Elagabani MN, Köhr G, Kornau HC. The small GTPase Arf6 is dysregulated in a mouse model for fragile X syndrome. J Neurochem 2020; 157:666-683. [PMID: 33125726 DOI: 10.1111/jnc.15230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/09/2020] [Accepted: 10/27/2020] [Indexed: 11/29/2022]
Abstract
Fragile X syndrome (FXS), the most common inherited cause of intellectual disability, results from silencing of the fragile X mental retardation gene 1 (FMR1). The analyses of FXS patients' brain autopsies revealed an increased density of immature dendritic spines in cortical areas. We hypothesize that the small GTPase Arf6, an actin regulator critical for the development of glutamatergic synapses and dendritic spines, is implicated in FXS. Here, we determined the fraction of active, GTP-bound Arf6 in cortical neuron cultures and synaptoneurosomes from Fmr1 knockout mice, measured actin polymerization in neurons expressing Arf6 mutants with variant GTP- or GDP-binding properties, and recorded hippocampal long-term depression induced by metabotropic glutamate receptors (mGluR-LTD) in acute brain slices. We detected a persistently elevated Arf6 activity, a loss of Arf6 sensitivity to synaptic stimulation and an increased Arf6-dependent dendritic actin polymerization in mature Fmr1 knockout neurons. Similar imbalances in Arf6-GTP levels and actin filament assembly were caused in wild-type neurons by RNAi-mediated depletion of the postsynaptic Arf6 guanylate exchange factors IQSEC1 (BRAG2) or IQSEC2 (BRAG1). Targeted deletion of Iqsec1 in hippocampal neurons of 3-week-old mice interfered with mGluR-LTD in wild-type, but not in Fmr1 knockout mice. Collectively, these data suggest an aberrant Arf6 regulation in Fmr1 knockout neurons with consequences for the actin cytoskeleton, spine morphology, and synaptic plasticity. Moreover, FXS and syndromes caused by genetic variants in IQSEC1 and IQSEC2 share intellectual disabilities and developmental delay as main symptoms. Therefore, dysregulation of Arf6 may contribute to the cognitive impairment in FXS.
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Affiliation(s)
- Dušica Briševac
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Ralf Scholz
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Dan Du
- Central Institute of Mental Health, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Georg Köhr
- Central Institute of Mental Health, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.,Department of Neurophysiology, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Hans-Christian Kornau
- Neuroscience Research Center (NWFZ), Charité - Universitätsmedizin Berlin, Berlin, Germany.,Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.,German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
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53
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Garcia-Forn M, Boitnott A, Akpinar Z, De Rubeis S. Linking Autism Risk Genes to Disruption of Cortical Development. Cells 2020; 9:cells9112500. [PMID: 33218123 PMCID: PMC7698947 DOI: 10.3390/cells9112500] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/10/2020] [Accepted: 11/15/2020] [Indexed: 02/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder characterized by impairments in social communication and social interaction, and the presence of repetitive behaviors and/or restricted interests. In the past few years, large-scale whole-exome sequencing and genome-wide association studies have made enormous progress in our understanding of the genetic risk architecture of ASD. While showing a complex and heterogeneous landscape, these studies have led to the identification of genetic loci associated with ASD risk. The intersection of genetic and transcriptomic analyses have also begun to shed light on functional convergences between risk genes, with the mid-fetal development of the cerebral cortex emerging as a critical nexus for ASD. In this review, we provide a concise summary of the latest genetic discoveries on ASD. We then discuss the studies in postmortem tissues, stem cell models, and rodent models that implicate recently identified ASD risk genes in cortical development.
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Affiliation(s)
- Marta Garcia-Forn
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.G.-F.); (A.B.); (Z.A.)
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andrea Boitnott
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.G.-F.); (A.B.); (Z.A.)
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Zeynep Akpinar
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.G.-F.); (A.B.); (Z.A.)
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychology, College of Arts and Sciences, New York University, New York, NY 10003, USA
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.G.-F.); (A.B.); (Z.A.)
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Correspondence: ; Tel.: +1-212-241-0179
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Tomorsky J, Parker PRL, Doe CQ, Niell CM. Precise levels of nectin-3 are required for proper synapse formation in postnatal visual cortex. Neural Dev 2020; 15:13. [PMID: 33160402 PMCID: PMC7648993 DOI: 10.1186/s13064-020-00150-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Developing cortical neurons express a tightly choreographed sequence of cytoskeletal and transmembrane proteins to form and strengthen specific synaptic connections during circuit formation. Nectin-3 is a cell-adhesion molecule with previously described roles in synapse formation and maintenance. This protein and its binding partner, nectin-1, are selectively expressed in upper-layer neurons of mouse visual cortex, but their role in the development of cortical circuits is unknown. METHODS Here we block nectin-3 expression (via shRNA) or overexpress nectin-3 in developing layer 2/3 visual cortical neurons using in utero electroporation. We then assay dendritic spine densities at three developmental time points: eye opening (postnatal day (P)14), one week following eye opening after a period of heightened synaptogenesis (P21), and at the close of the critical period for ocular dominance plasticity (P35). RESULTS Knockdown of nectin-3 beginning at E15.5 or ~ P19 increased dendritic spine densities at P21 or P35, respectively. Conversely, overexpressing full length nectin-3 at E15.5 decreased dendritic spine densities when all ages were considered together. The effects of nectin-3 knockdown and overexpression on dendritic spine densities were most significant on proximal secondary apical dendrites. Interestingly, an even greater decrease in dendritic spine densities, particularly on basal dendrites at P21, was observed when we overexpressed nectin-3 lacking its afadin binding domain. CONCLUSION These data collectively suggest that the proper levels and functioning of nectin-3 facilitate normal synapse formation after eye opening on apical and basal dendrites in layer 2/3 of visual cortex.
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Affiliation(s)
- Johanna Tomorsky
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA.
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA.
- Stanford University, 318 Campus Drive, Stanford, CA, 94305, USA.
| | - Philip R L Parker
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Chris Q Doe
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA
- Institute of Molecular Biology, University of Oregon, Eugene, OR, 97403, USA
- Howard Hughes Medical Institute, University of Oregon, Eugene, OR, 97403, USA
| | - Cristopher M Niell
- Institute of Neuroscience, University of Oregon, Eugene, OR, 97403, USA.
- Department of Biology, University of Oregon, Eugene, OR, 97403, USA.
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55
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Feuge J, Scharkowski F, Michaelsen-Preusse K, Korte M. FMRP Modulates Activity-Dependent Spine Plasticity by Binding Cofilin1 mRNA and Regulating Localization and Local Translation. Cereb Cortex 2020; 29:5204-5216. [PMID: 30953439 DOI: 10.1093/cercor/bhz059] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/14/2019] [Accepted: 02/27/2019] [Indexed: 11/13/2022] Open
Abstract
Multiple variants of intellectual disability, e.g., the Fragile X Syndrome are associated with alterations in dendritic spine morphology, thereby pointing to dysregulated actin dynamics during development and processes of synaptic plasticity. Surprisingly, although the necessity of spine actin remodeling was demonstrated repeatedly, the importance and precise role of actin regulators is often undervalued. Here, we provide evidence that structural and functional plasticity are severely impaired after NMDAR-dependent LTP in the hippocampus of Fmr1 KO mice. We can link these defects to an aberrant activity-dependent regulation of Cofilin 1 (cof1) as activity-dependent modulations of local cof1 mRNA availability, local cof1 translation as well as total cof1 expression are impaired in the absence of FMRP. Finally, we can rescue activity-dependent structural plasticity in KO neurons by mimicking the regulation of cof1 observed in WT cells, thereby illustrating the potential of actin modulators to provide novel treatment strategies for the Fragile X Syndrome.
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Affiliation(s)
- Jonas Feuge
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, Germany
| | | | | | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, Germany.,Helmholtz Center for Infection Research, Research group Neuroinflammation and Neurodegeneration, Braunschweig, Germany
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56
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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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57
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Motanis H, Buonomano D. Decreased reproducibility and abnormal experience-dependent plasticity of network dynamics in Fragile X circuits. Sci Rep 2020; 10:14535. [PMID: 32884028 PMCID: PMC7471942 DOI: 10.1038/s41598-020-71333-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/10/2020] [Indexed: 02/06/2023] Open
Abstract
Fragile X syndrome is a neurodevelopmental disorder associated with a broad range of neural phenotypes. Interpreting these findings has proven challenging because some phenotypes may reflect compensatory mechanisms or normal forms of plasticity differentially engaged by experiential differences. To help minimize compensatory and experiential influences, we used an ex vivo approach to study network dynamics and plasticity of cortical microcircuits. In Fmr1-/y circuits, the spatiotemporal structure of Up-states was less reproducible, suggesting alterations in the plasticity mechanisms governing network activity. Chronic optical stimulation revealed normal homeostatic plasticity of Up-states, however, Fmr1-/y circuits exhibited abnormal experience-dependent plasticity as they did not adapt to chronically presented temporal patterns in an interval-specific manner. These results, suggest that while homeostatic plasticity is normal, Fmr1-/y circuits exhibit deficits in the ability to orchestrate multiple forms of synaptic plasticity and to adapt to sensory patterns in an experience-dependent manner-which is likely to contribute to learning deficits.
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Affiliation(s)
- Helen Motanis
- Departments of Neurobiology and Psychology, and Integrative Center for Learning and Memory, University of California, 630 Charles E Young Dr S, Center for Health Sciences Building, Los Angeles, CA, 90095, USA
| | - Dean Buonomano
- Departments of Neurobiology and Psychology, and Integrative Center for Learning and Memory, University of California, 630 Charles E Young Dr S, Center for Health Sciences Building, Los Angeles, CA, 90095, USA.
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58
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Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020. [DOI: 10.3389/fnsyn.2020.00036
expr 823669561 + 872784217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
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59
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Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020; 12:36. [PMID: 32982715 PMCID: PMC7484486 DOI: 10.3389/fnsyn.2020.00036] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022] Open
Abstract
Dendritic spines are small protrusions studding neuronal dendrites, first described in 1888 by Ramón y Cajal using his famous Golgi stainings. Around 50 years later the advance of electron microscopy (EM) confirmed Cajal's intuition that spines constitute the postsynaptic site of most excitatory synapses in the mammalian brain. The finding that spine density decreases between young and adult ages in fixed tissues suggested that spines are dynamic. It is only a decade ago that two-photon microscopy (TPM) has unambiguously proven the dynamic nature of spines, through the repeated imaging of single spines in live animals. Spine dynamics comprise formation, disappearance, and stabilization of spines and are modulated by neuronal activity and developmental age. Here, we review several emerging concepts in the field that start to answer the following key questions: What are the external signals triggering spine dynamics and the molecular mechanisms involved? What is, in return, the role of spine dynamics in circuit-rewiring, learning, and neuropsychiatric disorders?
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Affiliation(s)
- Karen Runge
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Carlos Cardoso
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Antoine de Chevigny
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
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60
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Comer AL, Carrier M, Tremblay MÈ, Cruz-Martín A. The Inflamed Brain in Schizophrenia: The Convergence of Genetic and Environmental Risk Factors That Lead to Uncontrolled Neuroinflammation. Front Cell Neurosci 2020; 14:274. [PMID: 33061891 PMCID: PMC7518314 DOI: 10.3389/fncel.2020.00274] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia is a disorder with a heterogeneous etiology involving complex interplay between genetic and environmental risk factors. The immune system is now known to play vital roles in nervous system function and pathology through regulating neuronal and glial development, synaptic plasticity, and behavior. In this regard, the immune system is positioned as a common link between the seemingly diverse genetic and environmental risk factors for schizophrenia. Synthesizing information about how the immune-brain axis is affected by multiple factors and how these factors might interact in schizophrenia is necessary to better understand the pathogenesis of this disease. Such knowledge will aid in the development of more translatable animal models that may lead to effective therapeutic interventions. Here, we provide an overview of the genetic risk factors for schizophrenia that modulate immune function. We also explore environmental factors for schizophrenia including exposure to pollution, gut dysbiosis, maternal immune activation and early-life stress, and how the consequences of these risk factors are linked to microglial function and dysfunction. We also propose that morphological and signaling deficits of the blood-brain barrier, as observed in some individuals with schizophrenia, can act as a gateway between peripheral and central nervous system inflammation, thus affecting microglia in their essential functions. Finally, we describe the diverse roles that microglia play in response to neuroinflammation and their impact on brain development and homeostasis, as well as schizophrenia pathophysiology.
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Affiliation(s)
- Ashley L. Comer
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Department of Biology, Boston University, Boston, MA, United States
- Neurophotonics Center, Boston University, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
| | - Micaël Carrier
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Alberto Cruz-Martín
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Department of Biology, Boston University, Boston, MA, United States
- Neurophotonics Center, Boston University, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University, Boston, MA, United States
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61
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Kennedy T, Rinker D, Broadie K. Genetic background mutations drive neural circuit hyperconnectivity in a fragile X syndrome model. BMC Biol 2020; 18:94. [PMID: 32731855 PMCID: PMC7392683 DOI: 10.1186/s12915-020-00817-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 06/19/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Neural circuits are initially assembled during development when neurons synapse with potential partners and later refined as appropriate connections stabilize into mature synapses while inappropriate contacts are eliminated. Disruptions to this synaptogenic process impair connectivity optimization and can cause neurodevelopmental disorders. Intellectual disability (ID) and autism spectrum disorder (ASD) are often characterized by synaptic overgrowth, with the maintenance of immature or inappropriate synapses. Such synaptogenic defects can occur through mutation of a single gene, such as fragile X mental retardation protein (FMRP) loss causing the neurodevelopmental disorder fragile X syndrome (FXS). FXS represents the leading heritable cause of ID and ASD, but many other genes that play roles in ID and ASD have yet to be identified. RESULTS In a Drosophila FXS disease model, one dfmr150M null mutant stock exhibits previously unreported axonal overgrowths at developmental and mature stages in the giant fiber (GF) escape circuit. These excess axon projections contain both chemical and electrical synapse markers, indicating mixed synaptic connections. Extensive analyses show these supernumerary synapses connect known GF circuit neurons, rather than new, inappropriate partners, indicating hyperconnectivity within the circuit. Despite the striking similarities to well-characterized FXS synaptic defects, this new GF circuit hyperconnectivity phenotype is driven by genetic background mutations in this dfmr150M stock. Similar GF circuit synaptic overgrowth is not observed in independent dfmr1 null alleles. Bulked segregant analysis (BSA) was combined with whole genome sequencing (WGS) to identify the quantitative trait loci (QTL) linked to neural circuit hyperconnectivity. The results reveal 8 QTL associated with inappropriate synapse formation and maintenance in the dfmr150M mutant background. CONCLUSIONS Synaptogenesis is a complex, precisely orchestrated neurodevelopmental process with a large cohort of gene products coordinating the connectivity, synaptic strength, and excitatory/inhibitory balance between neuronal partners. This work identifies a number of genetic regions that contain mutations disrupting proper synaptogenesis within a particularly well-mapped neural circuit. These QTL regions contain potential new genes involved in synapse formation and refinement. Given the similarity of the synaptic overgrowth phenotype to known ID and ASD inherited conditions, identifying these genes should increase our understanding of these devastating neurodevelopmental disease states.
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Affiliation(s)
- Tyler Kennedy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - David Rinker
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
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62
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Xu W, Löwel S, Schlüter OM. Silent Synapse-Based Mechanisms of Critical Period Plasticity. Front Cell Neurosci 2020; 14:213. [PMID: 32765222 PMCID: PMC7380267 DOI: 10.3389/fncel.2020.00213] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/17/2020] [Indexed: 01/08/2023] Open
Abstract
Critical periods are postnatal, restricted time windows of heightened plasticity in cortical neural networks, during which experience refines principal neuron wiring configurations. Here, we propose a model with two distinct types of synapses, innate synapses that establish rudimentary networks with innate function, and gestalt synapses that govern the experience-dependent refinement process. Nascent gestalt synapses are constantly formed as AMPA receptor-silent synapses which are the substrates for critical period plasticity. Experience drives the unsilencing and stabilization of gestalt synapses, as well as synapse pruning. This maturation process changes synapse patterning and consequently the functional architecture of cortical excitatory networks. Ocular dominance plasticity (ODP) in the primary visual cortex (V1) is an established experimental model for cortical plasticity. While converging evidence indicates that the start of the critical period for ODP is marked by the maturation of local inhibitory circuits, recent results support our model that critical periods end through the progressive maturation of gestalt synapses. The cooperative yet opposing function of two postsynaptic signaling scaffolds of excitatory synapses, PSD-93 and PSD-95, governs the maturation of gestalt synapses. Without those proteins, networks do not progress far beyond their innate functionality, resulting in rather impaired perception. While cortical networks remain malleable throughout life, the cellular mechanisms and the scope of critical period and adult plasticity differ. Critical period ODP is initiated with the depression of deprived eye responses in V1, whereas adult ODP is characterized by an initial increase in non-deprived eye responses. Our model proposes the gestalt synapse-based mechanism for critical period ODP, and also predicts a different mechanism for adult ODP based on the sparsity of nascent gestalt synapses at that age. Under our model, early life experience shapes the boundaries (the gestalt) for network function, both for its optimal performance as well as for its pathological state. Thus, reintroducing nascent gestalt synapses as plasticity substrates into adults may improve the network gestalt to facilitate functional recovery.
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Affiliation(s)
- Weifeng Xu
- Department of Neuroscience, Brown University, Providence, RI, United States
- Carney Institute for Brain Science, Brown University, Providence, RI, United States
| | - Siegrid Löwel
- Department of Systems Neuroscience, Johann-Friedrich-Blumenbach Institute for Zoology & Anthropology, University of Göttingen, Göttingen, Germany
- Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Oliver M. Schlüter
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
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63
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Lo LHY, Lai KO. Dysregulation of protein synthesis and dendritic spine morphogenesis in ASD: studies in human pluripotent stem cells. Mol Autism 2020; 11:40. [PMID: 32460854 PMCID: PMC7251853 DOI: 10.1186/s13229-020-00349-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 05/11/2020] [Indexed: 12/18/2022] Open
Abstract
Autism spectrum disorder (ASD) is a brain disorder that involves changes in neuronal connections. Abnormal morphology of dendritic spines on postsynaptic neurons has been observed in ASD patients and transgenic mice that model different monogenetic causes of ASD. A number of ASD-associated genetic variants are known to disrupt dendritic local protein synthesis, which is essential for spine morphogenesis, synaptic transmission, and plasticity. Most of our understanding on the molecular mechanism underlying ASD depends on studies using rodents. However, recent advance in human pluripotent stem cells and their neural differentiation provides a powerful alternative tool to understand the cellular aspects of human neurological disorders. In this review, we summarize recent progress on studying mRNA targeting and local protein synthesis in stem cell-derived neurons, and discuss how perturbation of these processes may impact synapse development and functions that are relevant to cognitive deficits in ASD.
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Affiliation(s)
- Louisa Hoi-Ying Lo
- School of Biomedical Sciences, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Kwok-On Lai
- School of Biomedical Sciences, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China. .,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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64
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Cheyne JE, Montgomery JM. The cellular and molecular basis of in vivo synaptic plasticity in rodents. Am J Physiol Cell Physiol 2020; 318:C1264-C1283. [PMID: 32320288 DOI: 10.1152/ajpcell.00416.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Plasticity within the neuronal networks of the brain underlies the ability to learn and retain new information. The initial discovery of synaptic plasticity occurred by measuring synaptic strength in vivo, applying external stimulation and observing an increase in synaptic strength termed long-term potentiation (LTP). Many of the molecular pathways involved in LTP and other forms of synaptic plasticity were subsequently uncovered in vitro. Over the last few decades, technological advances in recording and imaging in live animals have seen many of these molecular mechanisms confirmed in vivo, including structural changes both pre- and postsynaptically, changes in synaptic strength, and changes in neuronal excitability. A well-studied aspect of neuronal plasticity is the capacity of the brain to adapt to its environment, gained by comparing the brains of deprived and experienced animals in vivo, and in direct response to sensory stimuli. Multiple in vivo studies have also strongly linked plastic changes to memory by interfering with the expression of plasticity and by manipulating memory engrams. Plasticity in vivo also occurs in the absence of any form of external stimulation, i.e., during spontaneous network activity occurring with brain development. However, there is still much to learn about how plasticity is induced during natural learning and how this is altered in neurological disorders.
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Affiliation(s)
- Juliette E Cheyne
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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65
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Griffiths KK, Wang A, Wang L, Tracey M, Kleiner G, Quinzii CM, Sun L, Yang G, Perez-Zoghbi JF, Licznerski P, Yang M, Jonas EA, Levy RJ. Inefficient thermogenic mitochondrial respiration due to futile proton leak in a mouse model of fragile X syndrome. FASEB J 2020; 34:7404-7426. [PMID: 32307754 DOI: 10.1096/fj.202000283rr] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS) is the leading known inherited intellectual disability and the most common genetic cause of autism. The full mutation results in transcriptional silencing of the Fmr1 gene and loss of fragile X mental retardation protein (FMRP) expression. Defects in neuroenergetic capacity are known to cause a variety of neurodevelopmental disorders. Thus, we explored the integrity of forebrain mitochondria in Fmr1 knockout mice during the peak of synaptogenesis. We found inefficient thermogenic respiration due to futile proton leak in Fmr1 KO mitochondria caused by coenzyme Q (CoQ) deficiency and an open cyclosporine-sensitive channel. Repletion of mitochondrial CoQ within the Fmr1 KO forebrain closed the channel, blocked the pathological proton leak, restored rates of protein synthesis during synaptogenesis, and normalized the key phenotypic features later in life. The findings demonstrate that FMRP deficiency results in inefficient oxidative phosphorylation during the neurodevelopment and suggest that dysfunctional mitochondria may contribute to the FXS phenotype.
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Affiliation(s)
- Keren K Griffiths
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Aili Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Lifei Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Matthew Tracey
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Giulio Kleiner
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Catarina M Quinzii
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Linlin Sun
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Guang Yang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Jose F Perez-Zoghbi
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Pawel Licznerski
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Mu Yang
- Institute of Genomic Medicine and Psychiatry, Columbia University Medical Center, New York, NY, USA
| | - Elizabeth A Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Richard J Levy
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
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66
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Sun L, Zhou H, Cichon J, Yang G. Experience and sleep-dependent synaptic plasticity: from structure to activity. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190234. [PMID: 32248786 DOI: 10.1098/rstb.2019.0234] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Synaptic plasticity is important for learning and memory. With increasing evidence linking sleep states to changes in synaptic strength, an emerging view is that sleep promotes learning and memory by facilitating experience-induced synaptic plasticity. In this review, we summarize the recent progress on the function of sleep in regulating cortical synaptic plasticity. Specifically, we outline the electroencephalogram signatures of sleep states (e.g. slow-wave sleep, rapid eye movement sleep, spindles), sleep state-dependent changes in gene and synaptic protein expression, synaptic morphology, and neuronal and network activity. We highlight studies showing that post-experience sleep potentiates experience-induced synaptic changes and discuss the potential mechanisms that may link sleep-related brain activity to synaptic structural remodelling. We conclude that both synapse formation or strengthening and elimination or weakening occur across sleep. This sleep-dependent synaptic plasticity plays an important role in neuronal circuit refinement during development and after learning, while sleep disorders may contribute to or exacerbate the development of common neurological diseases. This article is part of the Theo Murphy meeting issue 'Memory reactivation: replaying events past, present and future'.
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Affiliation(s)
- Linlin Sun
- Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Hang Zhou
- Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Joseph Cichon
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Guang Yang
- Department of Anesthesiology, Columbia University, New York, NY, USA
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67
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Möhrle D, Fernández M, Peñagarikano O, Frick A, Allman B, Schmid S. What we can learn from a genetic rodent model about autism. Neurosci Biobehav Rev 2020; 109:29-53. [DOI: 10.1016/j.neubiorev.2019.12.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/28/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
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68
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Comer AL, Jinadasa T, Sriram B, Phadke RA, Kretsge LN, Nguyen TPH, Antognetti G, Gilbert JP, Lee J, Newmark ER, Hausmann FS, Rosenthal S, Liu Kot K, Liu Y, Yen WW, Dejanovic B, Cruz-Martín A. Increased expression of schizophrenia-associated gene C4 leads to hypoconnectivity of prefrontal cortex and reduced social interaction. PLoS Biol 2020; 18:e3000604. [PMID: 31935214 PMCID: PMC6959572 DOI: 10.1371/journal.pbio.3000604] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 12/19/2019] [Indexed: 01/10/2023] Open
Abstract
Schizophrenia is a severe mental disorder with an unclear pathophysiology. Increased expression of the immune gene C4 has been linked to a greater risk of developing schizophrenia; however, it is not known whether C4 plays a causative role in this brain disorder. Using confocal imaging and whole-cell electrophysiology, we demonstrate that overexpression of C4 in mouse prefrontal cortex neurons leads to perturbations in dendritic spine development and hypoconnectivity, which mirror neuropathologies found in schizophrenia patients. We find evidence that microglia-mediated synaptic engulfment is enhanced with increased expression of C4. We also show that C4-dependent circuit dysfunction in the frontal cortex leads to decreased social interactions in juvenile and adult mice. These results demonstrate that increased expression of the schizophrenia-associated gene C4 causes aberrant circuit wiring in the developing prefrontal cortex and leads to deficits in juvenile and adult social behavior, suggesting that altered C4 expression contributes directly to schizophrenia pathogenesis. Elevated expression of the gene encoding complement C4 is associated with an enhanced risk of schizophrenia, but the mechanism underlying this link is unclear. This study shows that overexpression of the C4 gene in mice leads to mis-wiring of the prefrontal cortex and deficits in social interactions.
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Affiliation(s)
- Ashley L. Comer
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- The Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, United States of America
- Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
| | - Tushare Jinadasa
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
| | - Balaji Sriram
- Research and Early Development, Biogen, Cambridge, Massachusetts, United States of America
| | - Rhushikesh A. Phadke
- Molecular Biology, Cell Biology and Biochemistry Program, Boston University, Boston, Massachusetts, United States of America
| | - Lisa N. Kretsge
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- The Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, United States of America
- Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
| | - Thanh P. H. Nguyen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Giovanna Antognetti
- Biologics Drug Discovery, Biogen, Cambridge, Massachusetts, United States of America
| | - James P. Gilbert
- External Innovations and New Indications, Biogen, Cambridge, Massachusetts, United States of America
| | - Jungjoon Lee
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Elena R. Newmark
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Frances S. Hausmann
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - SaraAnn Rosenthal
- Department of Biology, Connecticut College, New London, Connecticut, United States of America
| | - Kevin Liu Kot
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Yenyu Liu
- Biochemistry and Molecular Biology/Biotechnology Program, Boston University, Boston, Massachusetts, United States of America
| | - William W. Yen
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Borislav Dejanovic
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Alberto Cruz-Martín
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- The Graduate Program for Neuroscience, Boston University, Boston, Massachusetts, United States of America
- Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
- Molecular Biology, Cell Biology and Biochemistry Program, Boston University, Boston, Massachusetts, United States of America
- Department Pharmacology and Experimental Therapeutics, Boston University, Boston, Massachusetts, United States of America
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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69
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Impaired Reliability and Precision of Spiking in Adults But Not Juveniles in a Mouse Model of Fragile X Syndrome. eNeuro 2019; 6:ENEURO.0217-19.2019. [PMID: 31685673 PMCID: PMC6917895 DOI: 10.1523/eneuro.0217-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/26/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common source of intellectual disability and autism. Extensive studies have been performed on the network and behavioral correlates of the syndrome, but our knowledge about intrinsic conductance changes is still limited. In this study, we show a differential effect of FMRP knockout in different subsections of hippocampus using whole-cell patch clamp in mouse hippocampal slices. We observed no significant change in spike numbers in the CA1 region of hippocampus, but a significant increase in CA3, in juvenile mice. However, in adult mice we see a reduction in spike number in the CA1 with no significant difference in CA3. In addition, we see increased variability in spike numbers in CA1 cells following a variety of steady and modulated current step protocols. This effect emerges in adult mice (8 weeks) but not juvenile mice (4 weeks). This increased spiking variability was correlated with reduced spike number and with elevated AHP. The increased AHP arose from elevated SK currents (small conductance calcium-activated potassium channels), but other currents involved in medium AHP, such as Ih and M, were not significantly different. We obtained a partial rescue of the cellular variability phenotype when we blocked SK current using the specific blocker apamin. Our observations provide a single-cell correlate of the network observations of response variability and loss of synchronization, and suggest that the elevation of SK currents in FXS may provide a partial mechanistic explanation for this difference.
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70
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Linaro D, Vermaercke B, Iwata R, Ramaswamy A, Libé-Philippot B, Boubakar L, Davis BA, Wierda K, Davie K, Poovathingal S, Penttila PA, Bilheu A, De Bruyne L, Gall D, Conzelmann KK, Bonin V, Vanderhaeghen P. Xenotransplanted Human Cortical Neurons Reveal Species-Specific Development and Functional Integration into Mouse Visual Circuits. Neuron 2019; 104:972-986.e6. [PMID: 31761708 PMCID: PMC6899440 DOI: 10.1016/j.neuron.2019.10.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/12/2019] [Accepted: 09/30/2019] [Indexed: 12/31/2022]
Abstract
How neural circuits develop in the human brain has remained almost impossible to study at the neuronal level. Here, we investigate human cortical neuron development, plasticity, and function using a mouse/human chimera model in which xenotransplanted human cortical pyramidal neurons integrate as single cells into the mouse cortex. Combined neuronal tracing, electrophysiology, and in vivo structural and functional imaging of the transplanted cells reveal a coordinated developmental roadmap recapitulating key milestones of human cortical neuron development. The human neurons display a prolonged developmental timeline, indicating the neuron-intrinsic retention of juvenile properties as an important component of human brain neoteny. Following maturation, human neurons in the visual cortex display tuned, decorrelated responses to visual stimuli, like mouse neurons, demonstrating their capacity for physiological synaptic integration in host cortical circuits. These findings provide new insights into human neuronal development and open novel avenues for the study of human neuronal function and disease. Video Abstract
Cell-intrinsic mechanisms of human neoteny in mouse-human chimeric cerebral cortex Human neurons show prolonged maturation and single-cell integration in mouse cortex Stable dendritic spines and long-term synaptic plasticity in xenotransplanted neurons Human neurons show decorrelated activity and tuned responses to visual stimuli
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Affiliation(s)
- Daniele Linaro
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Ben Vermaercke
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven, Belgium
| | - Ryohei Iwata
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Arjun Ramaswamy
- Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven, Belgium; imec, 3001 Leuven, Belgium
| | - Baptiste Libé-Philippot
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Leila Boubakar
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Brittany A Davis
- Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Keimpe Wierda
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Kristofer Davie
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | | | | | - Angéline Bilheu
- Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Lore De Bruyne
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - David Gall
- Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium; Laboratoire de Physiologie et Pharmacologie and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer-Institute and Gene Center, Ludwig-Maximilians-Universität Munchen, 81377 Munich, Germany
| | - Vincent Bonin
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001 Leuven, Belgium; imec, 3001 Leuven, Belgium; Department of Biology and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; VIB, 3000 Leuven, Belgium.
| | - Pierre Vanderhaeghen
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium; Institut de Recherches en Biologie Humaine et Moléculaire (IRIBHM) and ULB Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium; VIB, 3000 Leuven, Belgium; Welbio, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
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71
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Evidence for a Contribution of the Nlgn3/Cyfip1/Fmr1 Pathway in the Pathophysiology of Autism Spectrum Disorders. Neuroscience 2019; 445:31-41. [PMID: 31705895 DOI: 10.1016/j.neuroscience.2019.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 10/06/2019] [Indexed: 12/15/2022]
Abstract
Autism Spectrum Disorders (ASD) are characterized by heterogeneity both in their presentation and their genetic aetiology. In order to discover points of convergence common to different cases of ASD, attempts were made to identify the biological pathways genes associated with ASD contribute to. Many of these genes were found to play a role in neuronal and synaptic development and function. Among these genes are FMR1, CYFIP1 and NLGN3, all present at the synapse and reliably linked to ASD. In this review, we evaluate the evidence for the contribution of these genes to the same biological pathway responsible for the regulation of structural and physiological plasticity. Alterations in dendritic spine density and turnover, as well as long-term depression (LTD), were found in mouse models of mutations of all three genes. This overlap in the phenotypes associated with these mouse models likely arises from the molecular interaction between the protein products of FMR1, CYFIP1, and NLG3. A number of other proteins linked to ASD are also likely to participate in these pathways, resulting in further downstream effects. Overall, a synaptic pathway centered around FMR1, CYFIP1, and NLG3 is likely to contribute to the phenotypes associated with structural and physiological plasticity characteristic of ASD.
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72
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Cheng K, Chen YS, Yue CX, Zhang SM, Pei YP, Cheng GR, Liu D, Xu L, Dong HX, Zeng Y. Calsyntenin-1 Negatively Regulates ICAM5 Accumulation in Postsynaptic Membrane and Influences Dendritic Spine Maturation in a Mouse Model of Fragile X Syndrome. Front Neurosci 2019; 13:1098. [PMID: 31680833 PMCID: PMC6813673 DOI: 10.3389/fnins.2019.01098] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 09/30/2019] [Indexed: 11/29/2022] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that causes intellectual disability, as well as the leading monogenic cause of autism spectrum disorders (ASD), in which neurons show aberrant dendritic spine structure. The reduction/absence of the functional FMRP protein, coded by the X-linked Fmr1 gene in humans, is responsible for the syndrome. Targets of FMRP, CLSTN1, and ICAM5, play critical roles in the maturation of dendritic spines, synapse formation and synaptic plasticity. However, the implication of CLSTN1 and ICAM5 in dendritic spine abnormalities and the underlying neuropathologic processes in FXS remain uninvestigated. In this study, we demonstrated that CLSTN1 co-localizes and co-transports with ICAM5 in cultured cortical neurons. Also we showed that shRNA-mediated downregulation of CLSTN1 in cultured WT neurons increases ICAM5 on the surface of synaptic membrane, subsequently affecting the maturation of dendritic spines. Whereas, normalization of CLSTN1 level in Fmr1 KO neurons reduces ICAM5 abundance and rescues impaired dendritic spine phenotypes. Most importantly, CLSTN1 protein is reduced in the postnatal medial prefrontal cortex of Fmr1 KO mice, which is correlated with increased ICAM5 levels on the surface of synapses and excessive filopodia-like spines. In conclusion, this study demonstrates that CLSTN1 plays a critical role in dendritic spine formation and maturation in FXS by regulating ICAM5 redistribution.
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Affiliation(s)
- Ke Cheng
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Yu-Shan Chen
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Chao-Xiong Yue
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Si-Ming Zhang
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Ya-Ping Pei
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Gui-Rong Cheng
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Dan Liu
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Lang Xu
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
| | - Hong-Xin Dong
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL, United States
| | - Yan Zeng
- Brain and Cognition Research Institute, Wuhan University of Science and Technology, Wuhan, China.,Big Data Science and Engineering Research Institute, Wuhan University of Science and Technology, Wuhan, China
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73
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He Q, Arroyo ED, Smukowski SN, Xu J, Piochon C, Savas JN, Portera-Cailliau C, Contractor A. Critical period inhibition of NKCC1 rectifies synapse plasticity in the somatosensory cortex and restores adult tactile response maps in fragile X mice. Mol Psychiatry 2019; 24:1732-1747. [PMID: 29703945 PMCID: PMC6204122 DOI: 10.1038/s41380-018-0048-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/10/2018] [Accepted: 02/19/2018] [Indexed: 12/15/2022]
Abstract
Sensory perturbations in visual, auditory and tactile perception are core problems in fragile X syndrome (FXS). In the Fmr1 knockout mouse model of FXS, the maturation of synapses and circuits during critical period (CP) development in the somatosensory cortex is delayed, but it is unclear how this contributes to altered tactile sensory processing in the mature CNS. Here we demonstrate that inhibiting the juvenile chloride co-transporter NKCC1, which contributes to altered chloride homeostasis in developing cortical neurons of FXS mice, rectifies the chloride imbalance in layer IV somatosensory cortex neurons and corrects the development of thalamocortical excitatory synapses during the CP. Comparison of protein abundances demonstrated that NKCC1 inhibition during early development caused a broad remodeling of the proteome in the barrel cortex. In addition, the abnormally large size of whisker-evoked cortical maps in adult Fmr1 knockout mice was corrected by rectifying the chloride imbalance during the early CP. These data demonstrate that correcting the disrupted driving force through GABAA receptors during the CP in cortical neurons restores their synaptic development, has an unexpectedly large effect on differentially expressed proteins, and produces a long-lasting correction of somatosensory circuit function in FXS mice.
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Affiliation(s)
- Qionger He
- Department of Physiology, Northwestern University Feinberg School of Medicine
| | - Erica D Arroyo
- Departments of Neurology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095
| | - Samuel N Smukowski
- Department of Neurology, Northwestern University Feinberg School of Medicine
| | - Jian Xu
- Department of Physiology, Northwestern University Feinberg School of Medicine
| | - Claire Piochon
- Department of Physiology, Northwestern University Feinberg School of Medicine
| | - Jeffrey N Savas
- Department of Neurology, Northwestern University Feinberg School of Medicine
| | - Carlos Portera-Cailliau
- Departments of Neurology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095
| | - Anis Contractor
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. .,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, 60611, USA.
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74
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Imbalance in the response of pre- and post-synaptic components to amyloidopathy. Sci Rep 2019; 9:14837. [PMID: 31619689 PMCID: PMC6795896 DOI: 10.1038/s41598-019-50781-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD)-associated synaptic dysfunction drives the progression of pathology from its earliest stages. Amyloid β (Aβ) species, both soluble and in plaque deposits, have been causally related to the progressive, structural and functional impairments observed in AD. It is, however, still unclear how Aβ plaques develop over time and how they progressively affect local synapse density and turnover. Here we observed, in a mouse model of AD, that Aβ plaques grow faster in the earlier stages of the disease and if their initial area is >500 µm2; this may be due to deposition occurring in the outer regions of the plaque, the plaque cloud. In addition, synaptic turnover is higher in the presence of amyloid pathology and this is paralleled by a reduction in pre- but not post-synaptic densities. Plaque proximity does not appear to have an impact on synaptic dynamics. These observations indicate an imbalance in the response of the pre- and post-synaptic terminals and that therapeutics, alongside targeting the underlying pathology, need to address changes in synapse dynamics.
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75
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Multifaceted Changes in Synaptic Composition and Astrocytic Involvement in a Mouse Model of Fragile X Syndrome. Sci Rep 2019; 9:13855. [PMID: 31554841 PMCID: PMC6761194 DOI: 10.1038/s41598-019-50240-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/09/2019] [Indexed: 12/20/2022] Open
Abstract
Fragile X Syndrome (FXS), a common inheritable form of intellectual disability, is known to alter neocortical circuits. However, its impact on the diverse synapse types comprising these circuits, or on the involvement of astrocytes, is not well known. We used immunofluorescent array tomography to quantify different synaptic populations and their association with astrocytes in layers 1 through 4 of the adult somatosensory cortex of a FXS mouse model, the FMR1 knockout mouse. The collected multi-channel data contained approximately 1.6 million synapses which were analyzed using a probabilistic synapse detector. Our study reveals complex, synapse-type and layer specific changes in the neocortical circuitry of FMR1 knockout mice. We report an increase of small glutamatergic VGluT1 synapses in layer 4 accompanied by a decrease in large VGluT1 synapses in layers 1 and 4. VGluT2 synapses show a rather consistent decrease in density in layers 1 and 2/3. In all layers, we observe the loss of large inhibitory synapses. Lastly, astrocytic association of excitatory synapses decreases. The ability to dissect the circuit deficits by synapse type and astrocytic involvement will be crucial for understanding how these changes affect circuit function, and ultimately defining targets for therapeutic intervention.
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76
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Nishiyama J. Plasticity of dendritic spines: Molecular function and dysfunction in neurodevelopmental disorders. Psychiatry Clin Neurosci 2019; 73:541-550. [PMID: 31215705 DOI: 10.1111/pcn.12899] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 06/04/2019] [Accepted: 06/06/2019] [Indexed: 02/06/2023]
Abstract
Dendritic spines are tiny postsynaptic protrusions from a dendrite that receive most of the excitatory synaptic input in the brain. Functional and structural changes in dendritic spines are critical for synaptic plasticity, a cellular model of learning and memory. Conversely, altered spine morphology and plasticity are common hallmarks of human neurodevelopmental disorders, such as intellectual disability and autism. The advances in molecular and optical techniques have allowed for exploration of dynamic changes in structure and signal transduction at single-spine resolution, providing significant insights into the molecular regulation underlying spine structural plasticity. Here, I review recent findings on: how synaptic stimulation leads to diverse forms of spine structural plasticity; how the associated biochemical signals are initiated and transmitted into neuronal compartments; and how disruption of single genes associated with neurodevelopmental disorders can lead to abnormal spine structure in human and mouse brains. In particular, I discuss the functions of the Ras superfamily of small GTPases in spatiotemporal regulation of the actin cytoskeleton and protein synthesis in dendritic spines. Multiple lines of evidence implicate disrupted Ras signaling pathways in the spine structural abnormalities observed in neurodevelopmental disorders. Both deficient and excessive Ras activities lead to disrupted spine structure and deficits in learning and memory. Dysregulation of spine Ras signaling, therefore, may play a key role in the pathogenesis of multiple neurodevelopmental disorders with distinct etiologies.
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Affiliation(s)
- Jun Nishiyama
- Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore Medical School, Singapore
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77
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Takahashi-Nakazato A, Parajuli LK, Iwasaki H, Tanaka S, Okabe S. Ultrastructural Observation of Glutamatergic Synapses by Focused Ion Beam Scanning Electron Microscopy (FIB/SEM). Methods Mol Biol 2019; 1941:17-27. [PMID: 30707424 DOI: 10.1007/978-1-4939-9077-1_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A thorough understanding of the synaptic ultrastructure is necessary to bridge our current knowledge gap about the relationship between neuronal structure and function. Recent development of focused ion beam scanning electron microscopy (FIB/SEM) has made it possible to image neuronal structures with high speed and efficiency. Here, we present our routine protocol for correlative two-photon microscopy and FIB/SEM imaging of glutamatergic synapses. Femtosecond-pulsed near-infrared laser was used to create fiducial marks around the dendrite of interest in aldehyde-fixed tissues. Thereafter, samples were subjected to en bloc staining with rOTO (reduced osmium tetroxide-thiocarbohydrazide-osmium tetroxide), followed by lead aspartate and uranyl acetate to enhance tissue contrast. Reliable detection of postsynaptic density (PSD) and plasma membrane contours by the sample preparation protocol optimized for FIB/SEM allows us to precisely evaluate morphological features that shape glutamatergic synaptic transmission.
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Affiliation(s)
- Ai Takahashi-Nakazato
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,CREST, JST, Tokyo, Japan
| | - Laxmi Kumar Parajuli
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,CREST, JST, Tokyo, Japan
| | - Hirohide Iwasaki
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,CREST, JST, Tokyo, Japan
| | - Shinji Tanaka
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,CREST, JST, Tokyo, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. .,CREST, JST, Tokyo, Japan.
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78
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Verma V, Paul A, Amrapali Vishwanath A, Vaidya B, Clement JP. Understanding intellectual disability and autism spectrum disorders from common mouse models: synapses to behaviour. Open Biol 2019; 9:180265. [PMID: 31185809 PMCID: PMC6597757 DOI: 10.1098/rsob.180265] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Normal brain development is highly dependent on the timely coordinated actions of genetic and environmental processes, and an aberration can lead to neurodevelopmental disorders (NDDs). Intellectual disability (ID) and autism spectrum disorders (ASDs) are a group of co-occurring NDDs that affect between 3% and 5% of the world population, thus presenting a great challenge to society. This problem calls for the need to understand the pathobiology of these disorders and to design new therapeutic strategies. One approach towards this has been the development of multiple analogous mouse models. This review discusses studies conducted in the mouse models of five major monogenic causes of ID and ASDs: Fmr1, Syngap1, Mecp2, Shank2/3 and Neuroligins/Neurnexins. These studies reveal that, despite having a diverse molecular origin, the effects of these mutations converge onto similar or related aetiological pathways, consequently giving rise to the typical phenotype of cognitive, social and emotional deficits that are characteristic of ID and ASDs. This convergence, therefore, highlights common pathological nodes that can be targeted for therapy. Other than conventional therapeutic strategies such as non-pharmacological corrective methods and symptomatic alleviation, multiple studies in mouse models have successfully proved the possibility of pharmacological and genetic therapy enabling functional recovery.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Abhik Paul
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Anjali Amrapali Vishwanath
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Bhupesh Vaidya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
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79
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Chidambaram SB, Rathipriya AG, Bolla SR, Bhat A, Ray B, Mahalakshmi AM, Manivasagam T, Thenmozhi AJ, Essa MM, Guillemin GJ, Chandra R, Sakharkar MK. Dendritic spines: Revisiting the physiological role. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:161-193. [PMID: 30654089 DOI: 10.1016/j.pnpbp.2019.01.005] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 01/04/2019] [Accepted: 01/12/2019] [Indexed: 12/11/2022]
Abstract
Dendritic spines are small, thin, specialized protrusions from neuronal dendrites, primarily localized in the excitatory synapses. Sophisticated imaging techniques revealed that dendritic spines are complex structures consisting of a dense network of cytoskeletal, transmembrane and scaffolding molecules, and numerous surface receptors. Molecular signaling pathways, mainly Rho and Ras family small GTPases pathways that converge on actin cytoskeleton, regulate the spine morphology and dynamics bi-directionally during synaptic activity. During synaptic plasticity the number and shapes of dendritic spines undergo radical reorganizations. Long-term potentiation (LTP) induction promote spine head enlargement and the formation and stabilization of new spines. Long-term depression (LTD) results in their shrinkage and retraction. Reports indicate increased spine density in the pyramidal neurons of autism and Fragile X syndrome patients and reduced density in the temporal gyrus loci of schizophrenic patients. Post-mortem reports of Alzheimer's brains showed reduced spine number in the hippocampus and cortex. This review highlights the spine morphogenesis process, the activity-dependent structural plasticity and mechanisms by which synaptic activity sculpts the dendritic spines, the structural and functional changes in spines during learning and memory using LTP and LTD processes. It also discusses on spine status in neurodegenerative diseases and the impact of nootropics and neuroprotective agents on the functional restoration of dendritic spines.
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Affiliation(s)
- Saravana Babu Chidambaram
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research (JSSAHER), Mysuru, Karnataka 570015, India.
| | - A G Rathipriya
- Food and Brain Research Foundation, Chennai, Tamil Nadu, India
| | - Srinivasa Rao Bolla
- Department of Anatomy, College of Medicine, Imam Abdulrahman Bin Faisal University, Damam, Saudi Arabia
| | - Abid Bhat
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research (JSSAHER), Mysuru, Karnataka 570015, India
| | - Bipul Ray
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research (JSSAHER), Mysuru, Karnataka 570015, India
| | - Arehally Marappa Mahalakshmi
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research (JSSAHER), Mysuru, Karnataka 570015, India
| | - Thamilarasan Manivasagam
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, Tamilnadu, India
| | - Arokiasamy Justin Thenmozhi
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, Tamilnadu, India
| | - Musthafa Mohamed Essa
- Department of Food Science and Nutrition, CAMS, Sultan Qaboos University, Muscat, Oman
| | - Gilles J Guillemin
- Neuropharmacology Group, Faculty of Medicine and Health Sciences, Deb Bailey MND Research Laboratory, Macquarie University, Sydney, NSW 2109, Australia
| | - Ramesh Chandra
- Department of Chemistry, Ambedkar Centre for BioMedical Research, Delhi University, Delhi 110007, India
| | - Meena Kishore Sakharkar
- College of Pharmacy and Nutrition, University of Saskatchewan, 107, Wiggins Road, Saskatoon, SK S7N 5C9, Canada.
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80
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Whyte AJ, Kietzman HW, Swanson AM, Butkovich LM, Barbee BR, Bassell GJ, Gross C, Gourley SL. Reward-Related Expectations Trigger Dendritic Spine Plasticity in the Mouse Ventrolateral Orbitofrontal Cortex. J Neurosci 2019; 39:4595-4605. [PMID: 30940719 PMCID: PMC6554633 DOI: 10.1523/jneurosci.2031-18.2019] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 03/07/2019] [Accepted: 03/26/2019] [Indexed: 02/06/2023] Open
Abstract
An essential aspect of goal-directed decision-making is selecting actions based on anticipated consequences, a process that involves the orbitofrontal cortex (OFC) and potentially, the plasticity of dendritic spines in this region. To investigate this possibility, we trained male and female mice to nose poke for food reinforcers, or we delivered the same number of food reinforcers non-contingently to separate mice. We then decreased the likelihood of reinforcement for trained mice, requiring them to modify action-outcome expectations. In a separate experiment, we blocked action-outcome updating via chemogenetic inactivation of the OFC. In both cases, successfully selecting actions based on their likely consequences was associated with fewer immature, thin-shaped dendritic spines and a greater proportion of mature, mushroom-shaped spines in the ventrolateral OFC. This pattern was distinct from spine loss associated with aging, and we identified no effects on hippocampal CA1 neurons. Given that the OFC is involved in prospective calculations of likely outcomes, even when they are not observable, constraining spinogenesis while preserving mature spines may be important for solidifying durable expectations. To investigate causal relationships, we inhibited the RNA-binding protein fragile X mental retardation protein (encoded by Fmr1), which constrains dendritic spine turnover. Ventrolateral OFC-selective Fmr1 knockdown recapitulated the behavioral effects of inducible OFC inactivation (and lesions; also shown here), impairing action-outcome conditioning, and caused dendritic spine excess. Our findings suggest that a proper balance of dendritic spine plasticity within the OFC is necessary for one's ability to select actions based on anticipated consequences.SIGNIFICANCE STATEMENT Navigating a changing environment requires associating actions with their likely outcomes and updating these associations when they change. Dendritic spine plasticity is likely involved, yet relationships are unconfirmed. Using behavioral, chemogenetic, and viral-mediated gene silencing strategies and high-resolution microscopy, we find that modifying action-outcome expectations is associated with fewer immature spines and a greater proportion of mature spines in the ventrolateral orbitofrontal cortex (OFC). Given that the OFC is involved in prospectively calculating the likely outcomes of one's behavior, even when they are not observable, constraining spinogenesis while preserving mature spines may be important for maintaining durable expectations.
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Affiliation(s)
- Alonzo J Whyte
- Departments of Cell Biology
- Pediatrics, Emory School of Medicine
- Yerkes National Primate Research Center
| | - Henry W Kietzman
- Pediatrics, Emory School of Medicine
- Yerkes National Primate Research Center
- Graduate Program in Neuroscience
| | - Andrew M Swanson
- Pediatrics, Emory School of Medicine
- Yerkes National Primate Research Center
- Graduate Program in Neuroscience
| | - Laura M Butkovich
- Pediatrics, Emory School of Medicine
- Yerkes National Primate Research Center
- Graduate Program in Neuroscience
| | - Britton R Barbee
- Pediatrics, Emory School of Medicine
- Yerkes National Primate Research Center
- Graduate Program in Molecular and Systems Pharmacology, Emory University, Atlanta, Georgia 30329
| | - Gary J Bassell
- Departments of Cell Biology
- Graduate Program in Neuroscience
| | - Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, and
- Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, Ohio 45267
| | - Shannon L Gourley
- Pediatrics, Emory School of Medicine,
- Yerkes National Primate Research Center
- Graduate Program in Neuroscience
- Graduate Program in Molecular and Systems Pharmacology, Emory University, Atlanta, Georgia 30329
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81
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Lazaro MT, Taxidis J, Shuman T, Bachmutsky I, Ikrar T, Santos R, Marcello GM, Mylavarapu A, Chandra S, Foreman A, Goli R, Tran D, Sharma N, Azhdam M, Dong H, Choe KY, Peñagarikano O, Masmanidis SC, Rácz B, Xu X, Geschwind DH, Golshani P. Reduced Prefrontal Synaptic Connectivity and Disturbed Oscillatory Population Dynamics in the CNTNAP2 Model of Autism. Cell Rep 2019; 27:2567-2578.e6. [PMID: 31141683 PMCID: PMC6553483 DOI: 10.1016/j.celrep.2019.05.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/20/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022] Open
Abstract
Loss-of-function mutations in CNTNAP2 cause a syndromic form of autism spectrum disorder in humans and produce social deficits, repetitive behaviors, and seizures in mice. However, the functional effects of these mutations at cellular and circuit levels remain elusive. Using laser-scanning photostimulation, whole-cell recordings, and electron microscopy, we found a dramatic decrease in excitatory and inhibitory synaptic inputs onto L2/3 pyramidal neurons of the medial prefrontal cortex (mPFC) of Cntnap2 knockout (KO) mice, concurrent with reduced spines and synapses, despite normal dendritic complexity and intrinsic excitability. Moreover, recording of mPFC local field potentials (LFPs) and unit spiking in vivo revealed increased activity in inhibitory neurons, reduced phase-locking to delta and theta oscillations, and delayed phase preference during locomotion. Excitatory neurons showed similar phase modulation changes at delta frequencies. Finally, pairwise correlations increased during immobility in KO mice. Thus, reduced synaptic inputs can yield perturbed temporal coordination of neuronal firing in cortical ensembles.
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Affiliation(s)
- Maria T Lazaro
- Interdepartmental Program for Neuroscience, UCLA, Los Angeles, CA, USA; Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Jiannis Taxidis
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Tristan Shuman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Iris Bachmutsky
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Taruna Ikrar
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Rommel Santos
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - G Mark Marcello
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Apoorva Mylavarapu
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Swasty Chandra
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Allison Foreman
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Rachna Goli
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Duy Tran
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Nikhil Sharma
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Michelle Azhdam
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Hongmei Dong
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Katrina Y Choe
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA
| | - Olga Peñagarikano
- Department of Pharmacology, School of Medicine, University of the Basque Country (UPV/EHU), Vizcaya, Spain; Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Madrid, Spain
| | - Sotiris C Masmanidis
- Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, UC Irvine, Irvine, CA, USA
| | - Daniel H Geschwind
- Center for Neurobehavioral Genetics, Semel Institute, UCLA, Los Angeles, CA, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Center for Autism Research and Treatment, Semel Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA.
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA; Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA, USA; Intellectual Development and Disabilities Research Center, UCLA, Los Angeles, CA, USA; West Los Angeles VA Medical Center, Los Angeles, CA.
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82
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Yang Y, Lu J, Zuo Y. Changes of Synaptic Structures Associated with Learning, Memory and Diseases. BRAIN SCIENCE ADVANCES 2019. [DOI: 10.26599/bsa.2018.2018.9050012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Synaptic plasticity is widely believed to be the cellular basis of learning and memory. It is influenced by various factors including development, sensory experiences, and brain disorders. Long-term synaptic plasticity is accompanied by protein synthesis and trafficking, leading to structural changes of the synapse. In this review, we focus on the synaptic structural plasticity, which has mainly been studied with in vivo two-photon laser scanning microscopy. We also discuss how a special type of synapses, the multi-contact synapses (including those formed by multi-synaptic boutons and multi-synaptic spines), are associated with experience and learning.
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Affiliation(s)
- Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ju Lu
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
| | - Yi Zuo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California 95064, USA
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83
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Urban P, Rezaei V, Bokota G, Denkiewicz M, Basu S, Plewczyński D. Dendritic Spines Taxonomy: The Functional and Structural Classification • Time-Dependent Probabilistic Model of Neuronal Activation. J Comput Biol 2019; 26:322-335. [PMID: 30810368 DOI: 10.1089/cmb.2018.0155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Categorizing spines into four subpopulations, stubby, mushroom, thin, or filopodia, is one of the common approaches in morphological analysis. Most cellular models describing synaptic plasticity, long-term potentiation (LTP), and long-term depression associate synaptic strength with either spine enlargement or spine shrinkage. Unfortunately, although we have a lot of available software with automatic spine segmentation and feature extraction methods, at present none of them allows for automatic and unbiased distinction between dendritic spine subpopulations, or for the detailed computational models of spine behavior. Therefore, we propose structural classification based on two different mathematical approaches: unsupervised construction of spine shape taxonomy based on arbitrary features (SpineTool) and supervised classification exploiting convolution kernels theory (2dSpAn). We compared two populations of spines in a form of static and dynamic data sets gathered at three time points. The dynamic data contain two sets of spines: the active set and the control set. The first population was stimulated with LTP, and the other population in its resting state was used as a control population. We propose one equation describing the distribution of variables that best fits all dendritic spine parameters.
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Affiliation(s)
- Paulina Urban
- 1 Center of New Technologies, University of Warsaw, Warsaw, Poland.,2 College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Vahid Rezaei
- 3 Department of Statistics, Faculty of Mathematics and Computer Sciences, Allameh Tabataba'i University, Tehran, Iran.,4 School of Biological Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
| | - Grzegorz Bokota
- 1 Center of New Technologies, University of Warsaw, Warsaw, Poland.,5 Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Michał Denkiewicz
- 1 Center of New Technologies, University of Warsaw, Warsaw, Poland.,2 College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Subhadip Basu
- 6 Department of Computer Science and Engineering, Jadavpur University, Kolkata, India
| | - Dariusz Plewczyński
- 1 Center of New Technologies, University of Warsaw, Warsaw, Poland.,7 Faculty of Mathematics and Information Science, Warsaw University of Technology, Warsaw, Poland
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84
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Arroyo ED, Fiole D, Mantri SS, Huang C, Portera-Cailliau C. Dendritic Spines in Early Postnatal Fragile X Mice Are Insensitive to Novel Sensory Experience. J Neurosci 2019; 39:412-419. [PMID: 30523064 PMCID: PMC6335755 DOI: 10.1523/jneurosci.1734-18.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 10/02/2018] [Accepted: 10/20/2018] [Indexed: 11/21/2022] Open
Abstract
Autism spectrum disorders are often associated with atypical sensory processing and sensory hypersensitivity, which can lead to maladaptive behaviors, such as tactile defensiveness. Such altered sensory perception in autism spectrum disorders could arise from disruptions in experience-dependent maturation of circuits during early brain development. Here, we tested the hypothesis that synaptic structures of primary somatosensory cortex (S1) neurons in Fragile X syndrome (FXS), which is a common inherited cause of autism, are not modulated by novel sensory information during development. We used chronic in vivo two-photon microscopy to image dendritic spines and axon "en passant" boutons of layer 2/3 pyramidal neurons in S1 of male and female WT and Fmr1 KO mice, a model of FXS. We found that a brief (overnight) exposure to dramatically enhance sensory inputs in the second postnatal week led to a significant increase in spine density in WT mice, but not in Fmr1 KO mice. In contrast, axon "en passant" boutons dynamics were impervious to this novel sensory experience in mice of both genotypes. We surmise that the inability of Fmr1 KO mice to modulate postsynaptic dynamics in response to increased sensory input, at a time when sensory information processing first comes online in S1 cortex, could play a role in altered sensory processing in FXS.SIGNIFICANCE STATEMENT Very few longitudinal in vivo imaging studies have investigated synaptic structure and dynamics in early postnatal mice. Moreover, those studies tend to focus on the effects of sensory input deprivation, a process that rarely occurs during normal brain development. Early postnatal imaging experiments are critical because a variety of neurodevelopmental disorders, including those characterized by autism, could result from alterations in how circuits are shaped by incoming sensory inputs during critical periods of development. In this study, we focused on a mouse model of Fragile X syndrome and demonstrate how dendritic spines are insensitive to a brief period of novel sensory experience.
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Affiliation(s)
- Erica D Arroyo
- Department of Neurology
- Neuroscience Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095
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85
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Yoong LF, Pai YJ, Moore AW. Stages and transitions in dendrite arbor differentiation. Neurosci Res 2019; 138:70-78. [DOI: 10.1016/j.neures.2018.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/10/2018] [Accepted: 08/14/2018] [Indexed: 12/26/2022]
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86
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Development of GABAergic Inputs Is Not Altered in Early Maturation of Adult Born Dentate Granule Neurons in Fragile X Mice. eNeuro 2018; 5:eN-NRS-0137-18. [PMID: 30627633 PMCID: PMC6325535 DOI: 10.1523/eneuro.0137-18.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/27/2018] [Accepted: 10/17/2018] [Indexed: 02/08/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited mental retardation and the most common known cause of autism. Loss of fragile X mental retardation protein (FMRP) in mice (Fmr1 KO) leads to altered synaptic and circuit maturation in the hippocampus that is correlated with alterations in hippocampal-dependent behaviors. Previous studies have demonstrated that loss of FMRP increased the rate of proliferation of progenitor cells and altered their fate specification in adult Fmr1 KO mice. While these studies clearly demonstrate a role for FMRP in adult neurogenesis in the hippocampus, it is not known whether the functional synaptic maturation and integration of adult-born dentate granule cells (abDGCs) into hippocampal circuits is affected in Fmr1 KO mice. Here, we used retroviral labeling to birthdate abDGCs in Fmr1 KO mice which allowed us to perform targeted patch clamp recording to measure the development of synaptic inputs to these neurons at precise time points after differentiation. The frequency and amplitude of spontaneous GABAergic events increased over the first three weeks after differentiation; however, this normal development of GABAergic synapses was not altered in Fmr1 KO mice. Furthermore, the relatively depolarized GABA reversal potential (EGABA) in immature abDGCs was unaffected by loss of FMRP as was the development of dendritic arbor of the adult generated neurons. These studies systematically characterized the functional development of abDGCs during the first four weeks after differentiation and demonstrate that the maturation of GABAergic synaptic inputs to these neurons is not grossly affected by the loss of FMRP.
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87
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Cortical dendritic spine development and plasticity: insights from in vivo imaging. Curr Opin Neurobiol 2018; 53:76-82. [DOI: 10.1016/j.conb.2018.06.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 01/14/2023]
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88
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In Vivo Volume Dynamics of Dendritic Spines in the Neocortex of Wild-Type and Fmr1 KO Mice. eNeuro 2018; 5:eN-NWR-0282-18. [PMID: 30417082 PMCID: PMC6223115 DOI: 10.1523/eneuro.0282-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/30/2018] [Accepted: 10/03/2018] [Indexed: 02/06/2023] Open
Abstract
Excitatory synapses are often formed at small protrusions of dendrite, called dendritic spines, in most projection neurons, and the spine-head volumes show strong correlations with synaptic connectivity. We examined the dynamics of spine volume in the adult mouse visual cortex using time-lapse in vivo two-photon imaging with a resonant Galvano scanner. Contrary to expectations, we found that the spines in the adult neocortex showed fluctuations to a similar degree as that observed in young hippocampal preparations, but there were systematic differences in how the dynamics were dependent on spine volumes, thus allowing for fewer fluctuations in small spines, which could account for the relatively low turnover rates of neocortical spines in vivo. We found that spine volumes fluctuated to a greater extent in a mouse model (Fmr1 knockout) of fragile X mental retardation than in wild-type mice, and the spine turnover rates were also higher in Fmr1 knock-out mice. Such features of spine dynamics in Fmr1 knock-out mice could be represented by a single slope factor in our model. Our data and model indicate a small but significant change in the average spine volume and more eminent differences in the statistical distribution in Fmr1 knock-out mice even in adulthood, which reflects the abnormal in vivo dynamics of spine volumes.
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89
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Iritani S, Torii Y, Habuchi C, Sekiguchi H, Fujishiro H, Yoshida M, Go Y, Iriki A, Isoda M, Ozaki N. The neuropathological investigation of the brain in a monkey model of autism spectrum disorder with ABCA13 deletion. Int J Dev Neurosci 2018; 71:130-139. [PMID: 30201574 DOI: 10.1016/j.ijdevneu.2018.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/31/2018] [Accepted: 09/03/2018] [Indexed: 02/06/2023] Open
Abstract
The precise biological etiology of autism spectrum disorder (ASD) remains unknown. In this study, we investigated the neuropathology of a monkey model of autism Human ABCA13 is the largest ABC transporter protein, with a length of 5058 amino acids and a predicted molecular weight of >450 kDa. However, the function of this protein remains to be elucidated. This protein is thought to be associated with major psychiatric disease. Using this monkey model of autism with an ABCA13 deletion and a mutation of 5HT2c, we neuropathologically investigated the changes in the neuronal formation in the frontal cortex. As a result, the neuronal formation in the cortex was found to be disorganized with regard to the neuronal size and laminal distribution in the ABCA13 deletion monkey. The catecholaminergic and GABAergic neuronal systems, serotoninergic neuronal formation (5HT2c) were also found to be impaired by an immunohistochemical evaluation. This study suggested that ABCA13 deficit induces the impairment of neuronal maturation or migration, and the function of the neuronal network. This protein might thus play a role in the neurodevelopmental function of the central nervous system and the dysfunction of this protein may be a pathophysiological cause of mental disorders including autism.
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Affiliation(s)
- Shuji Iritani
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
| | - Youta Torii
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Chikako Habuchi
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hirotaka Sekiguchi
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hiroshige Fujishiro
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Mari Yoshida
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Aichi, Japan
| | - Yasuhiro Go
- Department of Brain Sciences, Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Aichi, Japan; Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Japan; The Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Astushi Iriki
- Laboratory for Symbolic Cognitive Developmen RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Masaki Isoda
- Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki, Aichi, Japan; Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, Wako, Saitama, Japan; Department of Physiology, Kansai Medical University School of Medicine, Hirakata, Osaka, Japan
| | - Norio Ozaki
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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90
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Ricard C, Arroyo ED, He CX, Portera-Cailliau C, Lepousez G, Canepari M, Fiole D. Two-photon probes for in vivo multicolor microscopy of the structure and signals of brain cells. Brain Struct Funct 2018; 223:3011-3043. [PMID: 29748872 PMCID: PMC6119111 DOI: 10.1007/s00429-018-1678-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/03/2018] [Indexed: 02/07/2023]
Abstract
Imaging the brain of living laboratory animals at a microscopic scale can be achieved by two-photon microscopy thanks to the high penetrability and low phototoxicity of the excitation wavelengths used. However, knowledge of the two-photon spectral properties of the myriad fluorescent probes is generally scarce and, for many, non-existent. In addition, the use of different measurement units in published reports further hinders the design of a comprehensive imaging experiment. In this review, we compile and homogenize the two-photon spectral properties of 280 fluorescent probes. We provide practical data, including the wavelengths for optimal two-photon excitation, the peak values of two-photon action cross section or molecular brightness, and the emission ranges. Beyond the spectroscopic description of these fluorophores, we discuss their binding to biological targets. This specificity allows in vivo imaging of cells, their processes, and even organelles and other subcellular structures in the brain. In addition to probes that monitor endogenous cell metabolism, studies of healthy and diseased brain benefit from the specific binding of certain probes to pathology-specific features, ranging from amyloid-β plaques to the autofluorescence of certain antibiotics. A special focus is placed on functional in vivo imaging using two-photon probes that sense specific ions or membrane potential, and that may be combined with optogenetic actuators. Being closely linked to their use, we examine the different routes of intravital delivery of these fluorescent probes according to the target. Finally, we discuss different approaches, strategies, and prerequisites for two-photon multicolor experiments in the brains of living laboratory animals.
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Affiliation(s)
- Clément Ricard
- Brain Physiology Laboratory, CNRS UMR 8118, 75006, Paris, France
- Faculté de Sciences Fondamentales et Biomédicales, Université Paris Descartes, PRES Sorbonne Paris Cité, 75006, Paris, France
- Fédération de Recherche en Neurosciences FR 3636, Paris, 75006, France
| | - Erica D Arroyo
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Cynthia X He
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Gabriel Lepousez
- Unité Perception et Mémoire, Département de Neuroscience, Institut Pasteur, 25 rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Marco Canepari
- Laboratory for Interdisciplinary Physics, UMR 5588 CNRS and Université Grenoble Alpes, 38402, Saint Martin d'Hères, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Grenoble, France
- Institut National de la Santé et Recherche Médicale (INSERM), Grenoble, France
| | - Daniel Fiole
- Unité Biothérapies anti-Infectieuses et Immunité, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, BP 73, 91223, Brétigny-sur-Orge cedex, France.
- Human Histopathology and Animal Models, Infection and Epidemiology Department, Institut Pasteur, 28 rue du docteur Roux, 75725, Paris Cedex 15, France.
- ESRF-The European Synchrotron, 38043, Grenoble cedex, France.
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91
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Ravanidis S, Kattan FG, Doxakis E. Unraveling the Pathways to Neuronal Homeostasis and Disease: Mechanistic Insights into the Role of RNA-Binding Proteins and Associated Factors. Int J Mol Sci 2018; 19:ijms19082280. [PMID: 30081499 PMCID: PMC6121432 DOI: 10.3390/ijms19082280] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The timing, dosage and location of gene expression are fundamental determinants of brain architectural complexity. In neurons, this is, primarily, achieved by specific sets of trans-acting RNA-binding proteins (RBPs) and their associated factors that bind to specific cis elements throughout the RNA sequence to regulate splicing, polyadenylation, stability, transport and localized translation at both axons and dendrites. Not surprisingly, misregulation of RBP expression or disruption of its function due to mutations or sequestration into nuclear or cytoplasmic inclusions have been linked to the pathogenesis of several neuropsychiatric and neurodegenerative disorders such as fragile-X syndrome, autism spectrum disorders, spinal muscular atrophy, amyotrophic lateral sclerosis and frontotemporal dementia. This review discusses the roles of Pumilio, Staufen, IGF2BP, FMRP, Sam68, CPEB, NOVA, ELAVL, SMN, TDP43, FUS, TAF15, and TIA1/TIAR in RNA metabolism by analyzing their specific molecular and cellular function, the neurological symptoms associated with their perturbation, and their axodendritic transport/localization along with their target mRNAs as part of larger macromolecular complexes termed ribonucleoprotein (RNP) granules.
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Affiliation(s)
- Stylianos Ravanidis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Fedon-Giasin Kattan
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Epaminondas Doxakis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
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92
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Neuroligin 1, 2, and 3 Regulation at the Synapse: FMRP-Dependent Translation and Activity-Induced Proteolytic Cleavage. Mol Neurobiol 2018; 56:2741-2759. [PMID: 30056576 PMCID: PMC6459971 DOI: 10.1007/s12035-018-1243-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 07/15/2018] [Indexed: 12/19/2022]
Abstract
Neuroligins (NLGNs) are cell adhesion molecules located on the postsynaptic side of the synapse that interact with their presynaptic partners neurexins to maintain trans-synaptic connection. Fragile X syndrome (FXS) is a common neurodevelopmental disease that often co-occurs with autism and is caused by the lack of fragile X mental retardation protein (FMRP) expression. To gain an insight into the molecular interactions between the autism-related genes, we sought to determine whether FMRP controls the synaptic levels of NLGNs. We show evidences that FMRP associates with Nlgn1, Nlgn2, and Nlgn3 mRNAs in vitro in both synaptoneurosomes and neuronal cultures. Next, we confirm local translation of Nlgn1, Nlgn2, and Nlgn3 mRNAs to be synaptically regulated by FMRP. As a consequence of elevated Nlgns mRNA translation Fmr1 KO mice exhibit increased incorporation of NLGN1 and NLGN3 into the postsynaptic membrane. Finally, we show that neuroligins synaptic level is precisely and dynamically regulated by their rapid proteolytic cleavage upon NMDA receptor stimulation in both wild type and Fmr1 KO mice. In aggregate, our study provides a novel approach to understand the molecular basis of FXS by linking the dysregulated synaptic expression of NLGNs with FMRP.
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93
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He CX, Arroyo ED, Cantu DA, Goel A, Portera-Cailliau C. A Versatile Method for Viral Transfection of Calcium Indicators in the Neonatal Mouse Brain. Front Neural Circuits 2018; 12:56. [PMID: 30083093 PMCID: PMC6064716 DOI: 10.3389/fncir.2018.00056] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/29/2018] [Indexed: 12/24/2022] Open
Abstract
The first three postnatal weeks in rodents are a time when sensory experience drives the maturation of brain circuits, an important process that is not yet well understood. Alterations in this critical period of experience-dependent circuit assembly and plasticity contribute to several neurodevelopmental disorders, such as autism, epilepsy, and schizophrenia. Therefore, techniques for recording network activity and tracing neuronal connectivity over this time period are necessary for delineating circuit refinement in typical development and how it deviates in disease. Calcium imaging with GCaMP6 and other genetically encoded indicators is rapidly becoming the preferred method for recording network activity at the single-synapse and single-cell level in vivo, especially in genetically identified neuronal populations. We describe a protocol for intracortical injection of recombinant adeno-associated viruses in P1 neonatal mice and demonstrate its use for longitudinal imaging of GCaMP6s in the same neurons over several weeks to characterize the developmental desynchronization of cortical network activity. Our approach is ideally suited for chronic in vivo two-photon calcium imaging of neuronal activity from synapses to entire networks during the early postnatal period.
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Affiliation(s)
- Cynthia X He
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,Neuroscience Interdepartmental Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,UCLA-Caltech Medical Scientist Training Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States
| | - Erica D Arroyo
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,Neuroscience Interdepartmental Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States
| | - Daniel A Cantu
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,Neuroscience Interdepartmental Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States
| | - Anubhuti Goel
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,UCLA-Caltech Medical Scientist Training Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, United States
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94
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Michaelsen‐Preusse K, Feuge J, Korte M. Imbalance of synaptic actin dynamics as a key to fragile X syndrome? J Physiol 2018; 596:2773-2782. [PMID: 29380377 PMCID: PMC6046079 DOI: 10.1113/jp275571] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/09/2018] [Indexed: 11/08/2022] Open
Abstract
Our experiences and memories define who we are, and evidence has accumulated that memory formation is dependent on functional and structural adaptations of synaptic structures in our brain. Especially dendritic spines, the postsynaptic compartments of synapses show a strong structure-to-function relationship and a high degree of structural plasticity. Although the molecular mechanisms are not completely understood, it is known that these modifications are highly dependent on the actin cytoskeleton, the major cytoskeletal component of the spine. Given the crucial involvement of actin in these mechanisms, dysregulations of spine actin dynamics (reflected by alterations in dendritic spine morphology) can be found in a variety of neurological disorders ranging from schizophrenia to several forms of autism spectrum disorders such as fragile X syndrome (FXS). FXS is caused by a single mutation leading to an inactivation of the X-linked fragile X mental retardation 1 gene and loss of its gene product, the RNA-binding protein fragile X mental retardation protein 1 (FMRP), which normally can be found both pre- and postsynaptically. FMRP is involved in mRNA transport as well as regulation of local translation at the synapse, and although hundreds of FMRP-target mRNAs could be identified only a very few interactions between FMRP and actin-regulating proteins have been reported and validated. In this review we give an overview of recent work by our lab and others providing evidence that dysregulated actin dynamics might indeed be at the very base of a deeper understanding of neurological disorders ranging from cognitive impairment to the autism spectrum.
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Affiliation(s)
- Kristin Michaelsen‐Preusse
- Zoological Institute, Division of Cellular NeurobiologyTU BraunschweigSpielmannstr. 7Braunschweig38106Germany
| | - Jonas Feuge
- Zoological Institute, Division of Cellular NeurobiologyTU BraunschweigSpielmannstr. 7Braunschweig38106Germany
| | - Martin Korte
- Zoological Institute, Division of Cellular NeurobiologyTU BraunschweigSpielmannstr. 7Braunschweig38106Germany
- Helmholtz Centre for Infection ResearchAG NINDInhoffenstr. 7Braunschweig38124Germany
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95
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Nakai N, Takumi T, Nakai J, Sato M. Common Defects of Spine Dynamics and Circuit Function in Neurodevelopmental Disorders: A Systematic Review of Findings From in Vivo Optical Imaging of Mouse Models. Front Neurosci 2018; 12:412. [PMID: 29970983 PMCID: PMC6018076 DOI: 10.3389/fnins.2018.00412] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/29/2018] [Indexed: 11/18/2022] Open
Abstract
In vivo optical imaging is a powerful tool for revealing brain structure and function at both the circuit and cellular levels. Here, we provide a systematic review of findings obtained from in vivo imaging studies of mouse models of neurodevelopmental disorders, including the monogenic disorders fragile X syndrome, Rett syndrome, and Angelman syndrome, which are caused by genetic abnormalities of FMR1, MECP2, and UBE3A, as well as disorders caused by copy number variations (15q11-13 duplication and 22q11.2 deletion) and BTBR mice as an inbred strain model of autism spectrum disorder (ASD). Most studies visualize the structural and functional responsiveness of cerebral cortical neurons to sensory stimuli and the developmental and experience-dependent changes in these responses as a model of brain functions affected by these disorders. The optical imaging techniques include two-photon microscopy of fluorescently labeled dendritic spines or neurons loaded with fluorescent calcium indicators and macroscopic imaging of cortical activity using calcium indicators, voltage-sensitive dyes or intrinsic optical signals. Studies have revealed alterations in the density, stability, and turnover of dendritic spines, aberrant cortical sensory responses, impaired inhibitory function, and concomitant failure of circuit maturation as common causes for neurological deficits. Mechanistic hypotheses derived from in vivo imaging also provide new directions for therapeutic interventions. For instance, it was recently demonstrated that early postnatal administration of a selective serotonin reuptake inhibitor (SSRI) restores impaired cortical inhibitory function and ameliorates the aberrant social behaviors in a mouse model of ASD. We discuss the potential use of SSRIs for treating ASDs in light of these findings.
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Affiliation(s)
| | | | - Junichi Nakai
- RIKEN Center for Brain Science, Wako, Japan
- RIKEN Center for Advanced Intelligence Project, Tokyo, Japan
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Brain and Body System Science Institute, Saitama University, Saitama, Japan
| | - Masaaki Sato
- RIKEN Center for Brain Science, Wako, Japan
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan
- Brain and Body System Science Institute, Saitama University, Saitama, Japan
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96
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Suresh A, Dunaevsky A. Relationship Between Synaptic AMPAR and Spine Dynamics: Impairments in the FXS Mouse. Cereb Cortex 2018; 27:4244-4256. [PMID: 28541473 PMCID: PMC6057510 DOI: 10.1093/cercor/bhx128] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/04/2017] [Indexed: 12/26/2022] Open
Abstract
Structural dynamics of dendritic spines are important for memory and learning and are impaired in neurodevelopmental disorders such as fragile X syndrome. Spine dynamics are regulated by activity-dependent mechanisms that involve modulation of AMPA receptors (AMPAR); however, the relationship between AMPAR and spine dynamics in vivo and how these are altered in FXS mouse model is not known. Here, we tracked AMPAR and spines over multiple days in vivo in the cortex and found that dendritic spines in the fmr1 KO mouse were denser, smaller, had higher turnover rates and contained less sGluA2 compared to littermate controls. Although, KO spines maintained the relationship between AMPAR and spine stability, AMPAR levels in the KO were more dynamic with larger proportion of spines showing multiple dynamic events of AMPAR. Directional changes in sGluA2 were also observed in newly formed and eliminated spines, with KO spines displaying greater loss of AMPAR before elimination. Thus, we demonstrate that AMPAR levels within spines not are only continuously dynamic, but are also predictive of spine behavior, with impairments observed in the fmr1 KO mice.
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Affiliation(s)
| | - Anna Dunaevsky
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE 68198-5960, USA
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97
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Banerjee A, Ifrim MF, Valdez AN, Raj N, Bassell GJ. Aberrant RNA translation in fragile X syndrome: From FMRP mechanisms to emerging therapeutic strategies. Brain Res 2018; 1693:24-36. [PMID: 29653083 PMCID: PMC7377270 DOI: 10.1016/j.brainres.2018.04.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 02/07/2023]
Abstract
Research in the past decades has unfolded the multifaceted role of Fragile X mental retardation protein (FMRP) and how its absence contributes to the pathophysiology of Fragile X syndrome (FXS). Excess signaling through group 1 metabotropic glutamate receptors is commonly observed in mouse models of FXS, which in part is attributed to dysregulated translation and downstream signaling. Considering the wide spectrum of cellular and physiologic functions that loss of FMRP can affect in general, it may be advantageous to pursue disease mechanism based treatments that directly target translational components or signaling factors that regulate protein synthesis. Various FMRP targets upstream and downstream of the translational machinery are therefore being investigated to further our understanding of the molecular mechanism of RNA and protein synthesis dysregulation in FXS as well as test their potential role as therapeutic interventions to alleviate FXS associated symptoms. In this review, we will broadly discuss recent advancements made towards understanding the role of FMRP in translation regulation, new pre-clinical animal models with FMRP targets located at different levels of the translational and signal transduction pathways for therapeutic intervention as well as future use of stem cells to model FXS associated phenotypes.
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Affiliation(s)
- Anwesha Banerjee
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Marius F Ifrim
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Arielle N Valdez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nisha Raj
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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98
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Mulholland PJ, Teppen TL, Miller KM, Sexton HG, Pandey SC, Swartzwelder HS. Donepezil Reverses Dendritic Spine Morphology Adaptations and Fmr1 Epigenetic Modifications in Hippocampus of Adult Rats After Adolescent Alcohol Exposure. Alcohol Clin Exp Res 2018; 42:706-717. [PMID: 29336496 DOI: 10.1111/acer.13599] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/08/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Adolescent intermittent ethanol (AIE) exposure produces persistent impairments in cholinergic and epigenetic signaling and alters markers of synapses in the hippocampal formation, effects that are thought to drive hippocampal dysfunction in adult rodents. Donepezil (Aricept), a cholinesterase inhibitor, is used clinically to ameliorate memory-related cognitive deficits. Given that donepezil also prevents morphological impairment in preclinical models of neuropsychiatric disorders, we investigated the ability of donepezil to reverse morphological and epigenetic adaptations in the hippocampus of adult rats exposed to AIE. Because of the known relationship between dendritic spine density and morphology with the fragile X mental retardation 1 (Fmr1) gene, we also assessed Fmr1 expression and its epigenetic regulation in hippocampus after AIE and donepezil pretreatment. METHODS Adolescent rats were administered intermittent ethanol for 16 days starting on postnatal day 30. Rats were treated with donepezil (2.5 mg/kg) once a day for 4 days starting 20 days after the completion of AIE exposure. Brains were dissected out after the fourth donepezil dose, and spine analysis was completed in dentate gyrus granule neurons. A separate cohort of rats, treated identically, was used for molecular studies. RESULTS AIE exposure significantly reduced dendritic spine density and altered morphological characteristics of subclasses of dendritic spines. AIE exposure also increased mRNA levels and H3-K27 acetylation occupancy of the Fmr1 gene in hippocampus. Treatment of AIE-exposed adult rats with donepezil reversed both the dendritic spine adaptations and epigenetic modifications and expression of Fmr1. CONCLUSIONS These findings indicate that AIE produces long-lasting decreases in dendritic spine density and changes in Fmr1 gene expression in the hippocampal formation, suggesting morphological and epigenetic mechanisms underlying previously reported behavioral deficits after AIE. The reversal of these effects by subchronic, post-AIE donepezil treatment indicates that these AIE effects can be reversed by up-regulating cholinergic function.
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Affiliation(s)
- Patrick J Mulholland
- Departments of Neuroscience and Psychiatry & Behavioral Sciences, Charleston Alcohol Research Center, Charleston, South Carolina
| | - Tara L Teppen
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, Illinois
| | - Kelsey M Miller
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center and Durham VA Medical Center, Durham, North Carolina
| | - Hannah G Sexton
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center and Durham VA Medical Center, Durham, North Carolina
| | - Subhash C Pandey
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, Illinois
| | - H Scott Swartzwelder
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center and Durham VA Medical Center, Durham, North Carolina
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Hotspots of dendritic spine turnover facilitate clustered spine addition and learning and memory. Nat Commun 2018; 9:422. [PMID: 29379017 PMCID: PMC5789055 DOI: 10.1038/s41467-017-02751-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 12/22/2017] [Indexed: 01/08/2023] Open
Abstract
Modeling studies suggest that clustered structural plasticity of dendritic spines is an efficient mechanism of information storage in cortical circuits. However, why new clustered spines occur in specific locations and how their formation relates to learning and memory (L&M) remain unclear. Using in vivo two-photon microscopy, we track spine dynamics in retrosplenial cortex before, during, and after two forms of episodic-like learning and find that spine turnover before learning predicts future L&M performance, as well as the localization and rates of spine clustering. Consistent with the idea that these measures are causally related, a genetic manipulation that enhances spine turnover also enhances both L&M and spine clustering. Biophysically inspired modeling suggests turnover increases clustering, network sparsity, and memory capacity. These results support a hotspot model where spine turnover is the driver for localization of clustered spine formation, which serves to modulate network function, thus influencing storage capacity and L&M. Structural remodeling of dendritic spines is thought to be a mechanism of memory storage. Here, the authors look at how spine turnover and clustering predict future learning and memory performance, and see that a genetically modified mouse with enhanced spine turnover has enhanced learning.
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100
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Torres MD, Garcia O, Tang C, Busciglio J. Dendritic spine pathology and thrombospondin-1 deficits in Down syndrome. Free Radic Biol Med 2018; 114:10-14. [PMID: 28965914 PMCID: PMC7185223 DOI: 10.1016/j.freeradbiomed.2017.09.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 11/27/2022]
Abstract
Abnormal dendritic spine structure and function is one of the most prominent features associated with neurodevelopmental disorders including Down syndrome (DS). Defects in both spine morphology and spine density may underlie alterations in neuronal and synaptic plasticity, ultimately affecting cognitive ability. Here we briefly examine the role of astrocytes in spine alterations and more specifically the involvement of astrocyte-secreted thrombospondin 1 (TSP-1) deficits in spine and synaptic pathology in DS.
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Affiliation(s)
- Maria D Torres
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders (iMIND), and Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine, CA 92697, United States
| | - Octavio Garcia
- Facultad de Psicología, Universidad Nacional Autónoma de México, 04510 Coyoacán, Ciudad de México, México
| | - Cindy Tang
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders (iMIND), and Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine, CA 92697, United States
| | - Jorge Busciglio
- Department of Neurobiology and Behavior, Institute for Memory Impairments and Neurological Disorders (iMIND), and Center for the Neurobiology of Learning and Memory (CNLM), University of California, Irvine, CA 92697, United States.
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