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Brockhaus J, Kahl I, Ahmad M, Repetto D, Reissner C, Missler M. Conditional Knockout of Neurexins Alters the Contribution of Calcium Channel Subtypes to Presynaptic Ca 2+ Influx. Cells 2024; 13:981. [PMID: 38891114 PMCID: PMC11171642 DOI: 10.3390/cells13110981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 05/23/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Presynaptic Ca2+ influx through voltage-gated Ca2+ channels (VGCCs) is a key signal for synaptic vesicle release. Synaptic neurexins can partially determine the strength of transmission by regulating VGCCs. However, it is unknown whether neurexins modulate Ca2+ influx via all VGCC subtypes similarly. Here, we performed live cell imaging of synaptic boutons from primary hippocampal neurons with a Ca2+ indicator. We used the expression of inactive and active Cre recombinase to compare control to conditional knockout neurons lacking either all or selected neurexin variants. We found that reduced total presynaptic Ca2+ transients caused by the deletion of all neurexins were primarily due to the reduced contribution of P/Q-type VGCCs. The deletion of neurexin1α alone also reduced the total presynaptic Ca2+ influx but increased Ca2+ influx via N-type VGCCs. Moreover, we tested whether the decrease in Ca2+ influx induced by activation of cannabinoid receptor 1 (CB1-receptor) is modulated by neurexins. Unlike earlier observations emphasizing a role for β-neurexins, we found that the decrease in presynaptic Ca2+ transients induced by CB1-receptor activation depended more strongly on the presence of α-neurexins in hippocampal neurons. Together, our results suggest that neurexins have unique roles in the modulation of presynaptic Ca2+ influx through VGCC subtypes and that different neurexin variants may affect specific VGCCs.
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Affiliation(s)
- Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Iris Kahl
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Mohiuddin Ahmad
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Carsten Reissner
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
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2
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Jiang HH, Xu R, Nie X, Su Z, Xu X, Pang R, Zhou Y, Luo F. Neurexins control the strength and precise timing of glycinergic inhibition in the auditory brainstem. eLife 2024; 13:RP94315. [PMID: 38814174 PMCID: PMC11139475 DOI: 10.7554/elife.94315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024] Open
Abstract
Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are involved in shaping functional properties of the glycinergic synapses, which mediate prominent inhibition in the brainstem and spinal cord. To address these issues, we examined the role of neurexins in a model glycinergic synapse between the principal neuron in the medial nucleus of the trapezoid body (MNTB) and the principal neuron in the lateral superior olive (LSO) in the auditory brainstem. Combining RNAscope with stereotactic injection of AAV-Cre in the MNTB of neurexin1/2/3 conditional triple knockout mice, we showed that MNTB neurons highly express all isoforms of neurexins although their expression levels vary remarkably. Selective ablation of all neurexins in MNTB neurons not only reduced the amplitude but also altered the kinetics of the glycinergic synaptic transmission at LSO neurons. The synaptic dysfunctions primarily resulted from an impaired Ca2+ sensitivity of release and a loosened coupling between voltage-gated Ca2+ channels and synaptic vesicles. Together, our current findings demonstrate that neurexins are essential in controlling the strength and temporal precision of the glycinergic synapse, which therefore corroborates the role of neurexins as key presynaptic organizers in all major types of fast chemical synapses.
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Affiliation(s)
- He-Hai Jiang
- Guangzhou National LaboratoryGuangzhouChina
- Bioland LaboratoryGuangzhouChina
- School of Basic Medical Sciences, Guangzhou Medical UniversityGuangzhouChina
| | - Ruoxuan Xu
- Guangzhou National LaboratoryGuangzhouChina
| | | | | | | | - Ruiqi Pang
- Department of Neurobiology, School of Basic Medicine, Army Medical UniversityChongqingChina
- Advanced Institute for Brain and Intelligence, School of Medicine, Guangxi UniversityNanningChina
| | - Yi Zhou
- Department of Neurobiology, School of Basic Medicine, Army Medical UniversityChongqingChina
| | - Fujun Luo
- Guangzhou National LaboratoryGuangzhouChina
- School of Basic Medical Sciences, Guangzhou Medical UniversityGuangzhouChina
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3
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Khoja S, Chen LY. Conditional deletion of neurexin-2 impaired behavioral flexibility to alterations in action-outcome contingency. Sci Rep 2024; 14:10187. [PMID: 38702381 PMCID: PMC11068883 DOI: 10.1038/s41598-024-60760-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
Neurexins (Nrxns) are critical for synapse organization and their mutations have been documented in autism spectrum disorder, schizophrenia, and epilepsy. We recently reported that conditional deletion of Nrxn2, under the control of Emx1Cre promoter, predominately expressed in the neocortex and hippocampus (Emx1-Nrxn2 cKO mice) induced stereotyped patterns of behavior in mice, suggesting behavioral inflexibility. In this study, we investigated the effects of Nrxn2 deletion through two different conditional approaches targeting presynaptic cortical neurons projecting to dorsomedial striatum on the flexibility between goal-directed and habitual actions in response to devaluation of action-outcome (A-O) contingencies in an instrumental learning paradigm or upon reversal of A-O contingencies in a water T-maze paradigm. Nrxn2 deletion through both the conditional approaches induced an inability of mice to discriminate between goal-directed and habitual action strategies in their response to devaluation of A-O contingency. Emx1-Nrxn2 cKO mice exhibited reversal learning deficits, indicating their inability to adopt new action strategies. Overall, our studies showed that Nrxn2 deletion through two distinct conditional deletion approaches impaired flexibility in response to alterations in A-O contingencies. These investigations can lay the foundation for identification of novel genetic factors underlying behavioral inflexibility.
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Affiliation(s)
- Sheraz Khoja
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Lulu Y Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA.
- Center for Neurobiology of Learning and Memory, Herklotz Research Facility, University of California, Irvine, CA, 92697, USA.
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4
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Verpoort B, de Wit J. Cell Adhesion Molecule Signaling at the Synapse: Beyond the Scaffold. Cold Spring Harb Perspect Biol 2024; 16:a041501. [PMID: 38316556 PMCID: PMC11065171 DOI: 10.1101/cshperspect.a041501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Synapses are specialized intercellular junctions connecting pre- and postsynaptic neurons into functional neural circuits. Synaptic cell adhesion molecules (CAMs) constitute key players in synapse development that engage in homo- or heterophilic interactions across the synaptic cleft. Decades of research have identified numerous synaptic CAMs, mapped their trans-synaptic interactions, and determined their role in orchestrating synaptic connectivity. However, surprisingly little is known about the molecular mechanisms that translate trans-synaptic adhesion into the assembly of pre- and postsynaptic compartments. Here, we provide an overview of the intracellular signaling pathways that are engaged by synaptic CAMs and highlight outstanding issues to be addressed in future work.
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Affiliation(s)
- Ben Verpoort
- VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
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5
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Liakath-Ali K, Refaee R, Südhof TC. Cartography of teneurin and latrophilin expression reveals spatiotemporal axis heterogeneity in the mouse hippocampus during development. PLoS Biol 2024; 22:e3002599. [PMID: 38713721 PMCID: PMC11101112 DOI: 10.1371/journal.pbio.3002599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 05/17/2024] [Accepted: 03/26/2024] [Indexed: 05/09/2024] Open
Abstract
Synaptic adhesion molecules (SAMs) are evolutionarily conserved proteins that play an important role in the form and function of neuronal synapses. Teneurins (Tenms) and latrophilins (Lphns) are well-known cell adhesion molecules that form a transsynaptic complex. Recent studies suggest that Tenm3 and Lphn2 (gene symbol Adgrl2) are involved in hippocampal circuit assembly via their topographical expression. However, it is not known whether other teneurins and latrophilins display similar topographically restricted expression patterns during embryonic and postnatal development. Here, we reveal the cartography of all teneurin (Tenm1-4) and latrophilin (Lphn1-3 [Adgrl1-3]) paralog expression in the mouse hippocampus across prenatal and postnatal development as monitored by large-scale single-molecule RNA in situ hybridization mapping. Our results identify a striking heterogeneity in teneurin and latrophilin expression along the spatiotemporal axis of the hippocampus. Tenm2 and Tenm4 expression levels peak at the neonatal stage when compared to Tenm1 and Tenm3, while Tenm1 expression is restricted to the postnatal pyramidal cell layer. Tenm4 expression in the dentate gyrus (DG) exhibits an opposing topographical expression pattern in the embryonic and neonatal hippocampus. Our findings were validated by analyses of multiple RNA-seq datasets at bulk, single-cell, and spatial levels. Thus, our study presents a comprehensive spatiotemporal map of Tenm and Lphn expression in the hippocampus, showcasing their diverse expression patterns across developmental stages in distinct spatial axes.
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Affiliation(s)
- Kif Liakath-Ali
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Rebecca Refaee
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University, Stanford, California, United States of America
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Cooper JN, Mittal J, Sangadi A, Klassen DL, King AM, Zalta M, Mittal R, Eshraghi AA. Landscape of NRXN1 Gene Variants in Phenotypic Manifestations of Autism Spectrum Disorder: A Systematic Review. J Clin Med 2024; 13:2067. [PMID: 38610832 PMCID: PMC11012327 DOI: 10.3390/jcm13072067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/21/2024] [Accepted: 03/29/2024] [Indexed: 04/14/2024] Open
Abstract
Background: Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by social communication challenges and repetitive behaviors. Recent research has increasingly focused on the genetic underpinnings of ASD, with the Neurexin 1 (NRXN1) gene emerging as a key player. This comprehensive systematic review elucidates the contribution of NRXN1 gene variants in the pathophysiology of ASD. Methods: The protocol for this systematic review was designed a priori and was registered in the PROSPERO database (CRD42023450418). A risk of bias analysis was conducted using the Joanna Briggs Institute (JBI) critical appraisal tool. We examined various studies that link NRXN1 gene disruptions with ASD, discussing both the genotypic variability and the resulting phenotypic expressions. Results: Within this review, there was marked heterogeneity observed in ASD genotypic and phenotypic manifestations among individuals with NRXN1 mutations. The presence of NRXN1 mutations in this population emphasizes the gene's role in synaptic function and neural connectivity. Conclusion: This review not only highlights the role of NRXN1 in the pathophysiology of ASD but also highlights the need for further research to unravel the complex genetic underpinnings of the disorder. A better knowledge about the multifaceted role of NRXN1 in ASD can provide crucial insights into the neurobiological foundations of autism and pave the way for novel therapeutic strategies.
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Affiliation(s)
- Jaimee N. Cooper
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
- School of Medicine, New York Medical College, Valhalla, NY 10595, USA
| | - Jeenu Mittal
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Akhila Sangadi
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Delany L. Klassen
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Ava M. King
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Max Zalta
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Rahul Mittal
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
| | - Adrien A. Eshraghi
- Department of Otolaryngology, Hearing Research and Communication Disorders Laboratory, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (J.N.C.); (J.M.); (A.S.); (D.L.K.); (A.M.K.); (M.Z.); (R.M.)
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33146, USA
- Department of Pediatrics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Park SJ, Wang IH, Lee N, Jiang HC, Uemura T, Futai K, Kim D, Macosko E, Greer P. Combinatorial expression of neurexin genes regulates glomerular targeting by olfactory sensory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.587570. [PMID: 38617205 PMCID: PMC11014570 DOI: 10.1101/2024.04.01.587570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Precise connectivity between specific neurons is essential for the formation of the complex neural circuitry necessary for executing intricate motor behaviors and higher cognitive functions. While trans -interactions between synaptic membrane proteins have emerged as crucial elements in orchestrating the assembly of these neural circuits, the synaptic surface proteins involved in neuronal wiring remain largely unknown. Here, using unbiased single-cell transcriptomic and mouse genetic approaches, we uncover that the neurexin family of genes enables olfactory sensory neuron (OSNs) axons to form appropriate synaptic connections with their mitral and tufted (M/T) cell synaptic partners, within the mammalian olfactory system. Neurexin isoforms are differentially expressed within distinct populations of OSNs, resulting in unique pattern of neurexin expression that is specific to each OSN type, and synergistically cooperate to regulate axonal innervation, guiding OSN axons to their designated glomeruli. This process is facilitated through the interactions of neurexins with their postsynaptic partners, including neuroligins, which have distinct expression patterns in M/T cells. Our findings suggest a novel mechanism underpinning the precise assembly of olfactory neural circuits, driven by the trans -interaction between neurexins and their ligands.
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Shan D, Song Y, Zhang Y, Ho CW, Xia W, Li Z, Ge F, Ou Q, Dai Z, Dai Z. Neurexin dysfunction in neurodevelopmental and neuropsychiatric disorders: a PRIMSA-based systematic review through iPSC and animal models. Front Behav Neurosci 2024; 18:1297374. [PMID: 38380150 PMCID: PMC10876810 DOI: 10.3389/fnbeh.2024.1297374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/17/2024] [Indexed: 02/22/2024] Open
Abstract
Background Neurexins, essential synaptic proteins, are linked to neurodevelopmental and neuropsychiatric disorders like autism spectrum disorder (ASD) and schizophrenia. Objective Through this systematic review, we aimed to shed light on the relationship between neurexin dysfunction and its implications in neurodevelopmental and neuropsychiatric manifestations. Both animal and human-induced pluripotent stem cell (hiPSC) models served as our primary investigative platforms. Methods Utilizing the PRISMA 2020 guidelines, our search strategy involved scouring articles from the PubMed and Google Scholar databases covering a span of two decades (2003-2023). Of the initial collection, 27 rigorously evaluated studies formed the essence of our review. Results Our review suggested the significant ties between neurexin anomalies and neurodevelopmental and neuropsychiatric outcomes, most notably ASD. Rodent-based investigations delineated pronounced ASD-associated behaviors, and hiPSC models derived from ASD-diagnosed patients revealed the disruptions in calcium dynamics and synaptic activities. Additionally, our review underlined the integral role of specific neurexin variants, primarily NRXN1, in the pathology of schizophrenia. It was also evident from our observation that neurexin malfunctions were implicated in a broader array of these disorders, including ADHD, intellectual challenges, and seizure disorders. Conclusion This review accentuates the cardinal role neurexins play in the pathological process of neurodevelopmental and neuropsychiatric disorders. The findings underscore a critical need for standardized methodologies in developing animal and hiPSC models for future studies, aiming to minimize heterogeneity. Moreover, we highlight the need to expand research into less studied neurexin variants (i.e., NRXN2 and NRXN3), broadening the scope of our understanding in this field. Our observation also projects hiPSC models as potent tools for bridging research gaps, promoting translational research, and fostering the development of patient-specific therapeutic interventions.
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Affiliation(s)
- Dan Shan
- Department of Biobehavioral Sciences, Columbia University, New York, NY, United States
- Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
| | - Yuming Song
- School of Medical Imaging, Hebei Medical University, Shijiazhuang, China
| | - Yanyi Zhang
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Cheong Wong Ho
- School of Medicine, University of Galway, Galway, Ireland
| | - Wenxin Xia
- School of Medicine, University of Galway, Galway, Ireland
| | - Zhi Li
- College of Health, Medicine and Wellbeing, University of Newcastle, Newcastle, NSW, Australia
| | - Fenfen Ge
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
| | - Qifeng Ou
- School of Medicine, University of Galway, Galway, Ireland
| | - Zijie Dai
- Division of Biosciences, Faculty of Life Sciences, University College London, London, United Kingdom
| | - Zhihao Dai
- School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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Mohrmann L, Seebach J, Missler M, Rohlmann A. Distinct Alterations in Dendritic Spine Morphology in the Absence of β-Neurexins. Int J Mol Sci 2024; 25:1285. [PMID: 38279285 PMCID: PMC10817056 DOI: 10.3390/ijms25021285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 01/28/2024] Open
Abstract
Dendritic spines are essential for synaptic function because they constitute the postsynaptic compartment of the neurons that receives the most excitatory input. The extracellularly shorter variant of the presynaptic cell adhesion molecules neurexins, β-neurexin, has been implicated in various aspects of synaptic function, including neurotransmitter release. However, its role in developing or stabilizing dendritic spines as fundamental computational units of excitatory synapses has remained unclear. Here, we show through morphological analysis that the deletion of β-neurexins in hippocampal neurons in vitro and in hippocampal tissue in vivo affects presynaptic dense-core vesicles, as hypothesized earlier, and, unexpectedly, alters the postsynaptic spine structure. Specifically, we observed that the absence of β-neurexins led to an increase in filopodial-like protrusions in vitro and more mature mushroom-type spines in the CA1 region of adult knockout mice. In addition, the deletion of β-neurexins caused alterations in the spine head dimension and an increase in spines with perforations of their postsynaptic density but no changes in the overall number of spines or synapses. Our results indicate that presynaptic β-neurexins play a role across the synaptic cleft, possibly by aligning with postsynaptic binding partners and glutamate receptors via transsynaptic columns.
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Affiliation(s)
| | | | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, University Münster, 48149 Münster, Germany; (L.M.); (J.S.)
| | - Astrid Rohlmann
- Institute of Anatomy and Molecular Neurobiology, University Münster, 48149 Münster, Germany; (L.M.); (J.S.)
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Schaan Profes M, Tiroumalechetty A, Patel N, Lauar SS, Sidoli S, Kurshan PT. Characterization of the intracellular neurexin interactome by in vivo proximity ligation suggests its involvement in presynaptic actin assembly. PLoS Biol 2024; 22:e3002466. [PMID: 38252619 PMCID: PMC10802952 DOI: 10.1371/journal.pbio.3002466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 12/09/2023] [Indexed: 01/24/2024] Open
Abstract
Neurexins are highly spliced transmembrane cell adhesion molecules that bind an array of partners via their extracellular domains. However, much less is known about the signaling pathways downstream of neurexin's largely invariant intracellular domain (ICD). Caenorhabditis elegans contains a single neurexin gene that we have previously shown is required for presynaptic assembly and stabilization. To gain insight into the signaling pathways mediating neurexin's presynaptic functions, we employed a proximity ligation method, endogenously tagging neurexin's intracellular domain with the promiscuous biotin ligase TurboID, allowing us to isolate adjacent biotinylated proteins by streptavidin pull-down and mass spectrometry. We compared our experimental strain to a control strain in which neurexin, endogenously tagged with TurboID, was dispersed from presynaptic active zones by the deletion of its C-terminal PDZ-binding motif. Selection of this control strain, which differs from the experimental strain only in its synaptic localization, was critical to identifying interactions specifically occurring at synapses. Using this approach, we identified both known and novel intracellular interactors of neurexin, including active zone scaffolds, actin-binding proteins (including almost every member of the Arp2/3 complex), signaling molecules, and mediators of RNA trafficking, protein synthesis and degradation, among others. Characterization of mutants for candidate neurexin interactors revealed that they recapitulate aspects of the nrx-1(-) mutant phenotype, suggesting they may be involved in neurexin signaling. Finally, to investigate a possible role for neurexin in local actin assembly, we endogenously tagged its intracellular domain with actin depolymerizing and sequestering peptides (DeActs) and found that this led to defects in active zone assembly. Together, these results suggest neurexin's intracellular domain may be involved in presynaptic actin-assembly, and furthermore highlight a novel approach to achieving high specificity for in vivo proteomics experiments.
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Affiliation(s)
- Marcos Schaan Profes
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Araven Tiroumalechetty
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Neel Patel
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Stephanie S. Lauar
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Peri T. Kurshan
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Cowen MH, Reddy KC, Chalasani SH, Hart MP. Conserved autism-associated genes tune social feeding behavior in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570116. [PMID: 38106124 PMCID: PMC10723370 DOI: 10.1101/2023.12.05.570116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Animal foraging is an essential and evolutionarily conserved behavior that occurs in social and solitary contexts, but the underlying molecular pathways are not well defined. We discover that conserved autism-associated genes (NRXN1(nrx-1), NLGN3(nlg-1), GRIA1,2,3(glr-1), GRIA2(glr-2), and GLRA2,GABRA3(avr-15)) regulate aggregate feeding in C. elegans, a simple social behavior. NRX-1 functions in chemosensory neurons (ADL and ASH) independently of its postsynaptic partner NLG-1 to regulate social feeding. Glutamate from these neurons is also crucial for aggregate feeding, acting independently of NRX-1 and NLG-1. Compared to solitary counterparts, social animals show faster presynaptic release and more presynaptic release sites in ASH neurons, with only the latter requiring nrx-1. Disruption of these distinct signaling components additively converts behavior from social to solitary. Aggregation induced by circuit activation is also dependent on nrx-1. Collectively, we find that aggregate feeding is tuned by conserved autism-associated genes through complementary synaptic mechanisms, revealing molecular principles driving social feeding.
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Affiliation(s)
- Mara H. Cowen
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA
- Department of Genetics, University of Pennsylvania, Philadelphia, PA
- Autism Spectrum Program of Excellence, Perelman School of Medicine, Philadelphia, PA
| | - Kirthi C. Reddy
- Molecular Neurobiology Laboratory, Salk Institute, La Jolla, CA
| | | | - Michael P. Hart
- Department of Genetics, University of Pennsylvania, Philadelphia, PA
- Autism Spectrum Program of Excellence, Perelman School of Medicine, Philadelphia, PA
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Bastien BL, Cowen MH, Hart MP. Distinct neurexin isoforms cooperate to initiate and maintain foraging activity. Transl Psychiatry 2023; 13:367. [PMID: 38036526 PMCID: PMC10689797 DOI: 10.1038/s41398-023-02668-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 10/24/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023] Open
Abstract
Neurexins are synaptic adhesion molecules that play diverse roles in synaptic development, function, maintenance, and plasticity. Neurexin genes have been associated with changes in human behavior, where variants in NRXN1 are associated with autism, schizophrenia, and Tourette syndrome. While NRXN1, NRXN2, and NRXN3 all encode major α and β isoforms, NRXN1 uniquely encodes a γ isoform, for which mechanistic roles in behavior have yet to be defined. Here, we show that both α and γ isoforms of neurexin/nrx-1 are required for the C. elegans behavioral response to food deprivation, a sustained period of hyperactivity upon food loss. We find that the γ isoform regulates initiation and the α isoform regulates maintenance of the behavioral response to food deprivation, demonstrating cooperative function of multiple nrx-1 isoforms in regulating a sustained behavior. The γ isoform alters monoamine signaling via octopamine, relies on specific expression of NRX-1 isoforms throughout the relevant circuit, and is independent of neuroligin/nlg-1, the canonical trans-synaptic partner of nrx-1. The α isoform regulates the pre-synaptic structure of the octopamine producing RIC neuron and its maintenance role is conditional on neuroligin/nlg-1. Collectively, these results demonstrate that neurexin isoforms can have separate behavioral roles and act cooperatively across neuronal circuits to modify behavior, highlighting the need to directly analyze and consider all isoforms when defining the contribution of neurexins to behavior.
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Affiliation(s)
- Brandon L Bastien
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mara H Cowen
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael P Hart
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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13
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Connor SA, Siddiqui TJ. Synapse organizers as molecular codes for synaptic plasticity. Trends Neurosci 2023; 46:971-985. [PMID: 37652840 DOI: 10.1016/j.tins.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/13/2023] [Accepted: 08/03/2023] [Indexed: 09/02/2023]
Abstract
Synapse organizing proteins are multifaceted molecules that coordinate the complex processes of brain development and plasticity at the level of individual synapses. Their importance is demonstrated by the major brain disorders that emerge when their function is compromised. The mechanisms whereby the various families of organizers govern synapses are diverse, but converge on the structure, function, and plasticity of synapses. Therefore, synapse organizers regulate how synapses adapt to ongoing activity, a process central for determining the developmental trajectory of the brain and critical to all forms of cognition. Here, we explore how synapse organizers set the conditions for synaptic plasticity and the associated molecular events, which eventually link to behavioral features of neurodevelopmental and neuropsychiatric disorders. We also propose central questions on how synapse organizers influence network function through integrating nanoscale and circuit-level organization of the brain.
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Affiliation(s)
- Steven A Connor
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
| | - Tabrez J Siddiqui
- PrairieNeuro Research Centre, Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, MB R3E 0Z3, Canada; Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; The Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Program in Biomedical Engineering, University of Manitoba, Winnipeg, MB, Canada.
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14
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Molloy CJ, Cooke J, Gatford NJF, Rivera-Olvera A, Avazzadeh S, Homberg JR, Grandjean J, Fernandes C, Shen S, Loth E, Srivastava DP, Gallagher L. Bridging the translational gap: what can synaptopathies tell us about autism? Front Mol Neurosci 2023; 16:1191323. [PMID: 37441676 PMCID: PMC10333541 DOI: 10.3389/fnmol.2023.1191323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/24/2023] [Indexed: 07/15/2023] Open
Abstract
Multiple molecular pathways and cellular processes have been implicated in the neurobiology of autism and other neurodevelopmental conditions. There is a current focus on synaptic gene conditions, or synaptopathies, which refer to clinical conditions associated with rare genetic variants disrupting genes involved in synaptic biology. Synaptopathies are commonly associated with autism and developmental delay and may be associated with a range of other neuropsychiatric outcomes. Altered synaptic biology is suggested by both preclinical and clinical studies in autism based on evidence of differences in early brain structural development and altered glutamatergic and GABAergic neurotransmission potentially perturbing excitatory and inhibitory balance. This review focusses on the NRXN-NLGN-SHANK pathway, which is implicated in the synaptic assembly, trans-synaptic signalling, and synaptic functioning. We provide an overview of the insights from preclinical molecular studies of the pathway. Concentrating on NRXN1 deletion and SHANK3 mutations, we discuss emerging understanding of cellular processes and electrophysiology from induced pluripotent stem cells (iPSC) models derived from individuals with synaptopathies, neuroimaging and behavioural findings in animal models of Nrxn1 and Shank3 synaptic gene conditions, and key findings regarding autism features, brain and behavioural phenotypes from human clinical studies of synaptopathies. The identification of molecular-based biomarkers from preclinical models aims to advance the development of targeted therapeutic treatments. However, it remains challenging to translate preclinical animal models and iPSC studies to interpret human brain development and autism features. We discuss the existing challenges in preclinical and clinical synaptopathy research, and potential solutions to align methodologies across preclinical and clinical research. Bridging the translational gap between preclinical and clinical studies will be necessary to understand biological mechanisms, to identify targeted therapies, and ultimately to progress towards personalised approaches for complex neurodevelopmental conditions such as autism.
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Affiliation(s)
- Ciara J. Molloy
- Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Jennifer Cooke
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Nicholas J. F. Gatford
- Kavli Institute for Nanoscience Discovery, Nuffield Department of Clinical Neurosciences, University of Oxford, Medical Sciences Division, Oxford, United Kingdom
| | - Alejandro Rivera-Olvera
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Sahar Avazzadeh
- Physiology and Cellular Physiology Research Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, University of Galway, Galway, Ireland
| | - Judith R. Homberg
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Joanes Grandjean
- Physiology and Cellular Physiology Research Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, University of Galway, Galway, Ireland
- Department of Medical Imaging, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Cathy Fernandes
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Sanbing Shen
- Regenerative Medicine Institute, School of Medicine, University of Galway, Galway, Ireland
- FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons, Dublin, Ireland
| | - Eva Loth
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Deepak P. Srivastava
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Louise Gallagher
- Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
- The Hospital for SickKids, Toronto, ON, Canada
- The Peter Gilgan Centre for Research and Learning, SickKids Research Institute, Toronto, ON, Canada
- The Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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15
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Lu H, Zuo L, Roddick KM, Zhang P, Oku S, Garden J, Ge Y, Bellefontaine M, Delhaye M, Brown RE, Craig AM. Alternative splicing and heparan sulfation converge on neurexin-1 to control glutamatergic transmission and autism-related behaviors. Cell Rep 2023; 42:112714. [PMID: 37384525 DOI: 10.1016/j.celrep.2023.112714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 04/16/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023] Open
Abstract
Neurexin synaptic organizing proteins are central to a genetic risk pathway in neuropsychiatric disorders. Neurexins also exemplify molecular diversity in the brain, with over a thousand alternatively spliced forms and further structural heterogeneity contributed by heparan sulfate glycan modification. Yet, interactions between these modes of post-transcriptional and post-translational modification have not been studied. We reveal that these regulatory modes converge on neurexin-1 splice site 5 (S5): the S5 insert increases the number of heparan sulfate chains. This is associated with reduced neurexin-1 protein level and reduced glutamatergic neurotransmitter release. Exclusion of neurexin-1 S5 in mice boosts neurotransmission without altering the AMPA/NMDA ratio and shifts communication and repetitive behavior away from phenotypes associated with autism spectrum disorders. Thus, neurexin-1 S5 acts as a synaptic rheostat to impact behavior through the intersection of RNA processing and glycobiology. These findings position NRXN1 S5 as a potential therapeutic target to restore function in neuropsychiatric disorders.
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Affiliation(s)
- Hong Lu
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Long Zuo
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Kyle M Roddick
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Peng Zhang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Shinichiro Oku
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Jessica Garden
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Michael Bellefontaine
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Mathias Delhaye
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Richard E Brown
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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16
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Okuno Y, Sakoori K, Matsuyama K, Yamasaki M, Watanabe M, Hashimoto K, Watanabe T, Kano M. PTPδ is a presynaptic organizer for the formation and maintenance of climbing fiber to Purkinje cell synapses in the developing cerebellum. Front Mol Neurosci 2023; 16:1206245. [PMID: 37426069 PMCID: PMC10323364 DOI: 10.3389/fnmol.2023.1206245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 05/25/2023] [Indexed: 07/11/2023] Open
Abstract
Functionally mature neural circuits are shaped during postnatal development by eliminating redundant synapses formed during the perinatal period. In the cerebellum of neonatal rodents, each Purkinje cell (PC) receives synaptic inputs from multiple (more than 4) climbing fibers (CFs). During the first 3 postnatal weeks, synaptic inputs from a single CF become markedly larger and those from the other CFs are eliminated in each PC, leading to mono-innervation of each PC by a strong CF in adulthood. While molecules involved in the strengthening and elimination of CF synapses during postnatal development are being elucidated, much less is known about the molecular mechanisms underlying CF synapse formation during the early postnatal period. Here, we show experimental evidence that suggests that a synapse organizer, PTPδ, is required for early postnatal CF synapse formation and the subsequent establishment of CF to PC synaptic wiring. We showed that PTPδ was localized at CF-PC synapses from postnatal day 0 (P0) irrespective of the expression of Aldolase C (Aldoc), a major marker of PC that distinguishes the cerebellar compartments. We found that the extension of a single strong CF along PC dendrites (CF translocation) was impaired in global PTPδ knockout (KO) mice from P12 to P29-31 predominantly in PCs that did not express Aldoc [Aldoc (-) PCs]. We also demonstrated via morphological and electrophysiological analyses that the number of CFs innervating individual PCs in PTPδ KO mice were fewer than in wild-type (WT) mice from P3 to P13 with a significant decrease in the strength of CF synaptic inputs in cerebellar anterior lobules where most PCs are Aldoc (-). Furthermore, CF-specific PTPδ-knockdown (KD) caused a reduction in the number of CFs innervating PCs with decreased CF synaptic inputs at P10-13 in anterior lobules. We found a mild impairment of motor performance in adult PTPδ KO mice. These results indicate that PTPδ acts as a presynaptic organizer for CF-PC formation and is required for normal CF-PC synaptic transmission, CF translocation, and presumably CF synapse maintenance predominantly in Aldoc (-) PCs. Furthermore, this study suggests that the impaired CF-PC synapse formation and development by the lack of PTPδ causes mild impairment of motor performance.
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Affiliation(s)
- Yuto Okuno
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kazuto Sakoori
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kyoko Matsuyama
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Miwako Yamasaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takaki Watanabe
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Tokyo, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Tokyo, Japan
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17
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Feichtinger RG, Preisel M, Brugger K, Wortmann SB, Mayr JA. Case Report-An Inherited Loss-of-Function NRXN3 Variant Potentially Causes a Neurodevelopmental Disorder with Autism Consistent with Previously Described 14q24.3-31.1 Deletions. Genes (Basel) 2023; 14:1217. [PMID: 37372397 DOI: 10.3390/genes14061217] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Heterozygous, large-scale deletions at 14q24.3-31.1 affecting the neurexin-3 gene have been associated with neurodevelopmental disorders such as autism. Both "de novo" occurrences and inheritance from a healthy parent suggest incomplete penetrance and expressivity, especially in autism spectrum disorder. NRXN3 encodes neurexin-3, a neuronal cell surface protein involved in cell recognition and adhesion, as well as mediating intracellular signaling. NRXN3 is expressed in two distinct isoforms (alpha and beta) generated by alternative promoters and splicing. MM/Results: Using exome sequencing, we identified a monoallelic frameshift variant c.159_160del (p.Gln54AlafsTer50) in the NRXN3 beta isoform (NM_001272020.2) in a 5-year-old girl with developmental delay, autism spectrum disorder, and behavioral issues. This variant was inherited from her mother, who did not have any medical complaints. DISCUSSION This is the first detailed report of a loss-of-function variant in NRXN3 causing an identical phenotype, as reported for heterozygous large-scale deletions in the same genomic region, thereby confirming NRXN3 as a novel gene for neurodevelopmental disorders with autism.
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Affiliation(s)
- René G Feichtinger
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Martin Preisel
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Karin Brugger
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
| | - Saskia B Wortmann
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
- Amalia Children's Hospital, Radboudumc, 6525 HB Nijmegen, The Netherlands
| | - Johannes A Mayr
- University Children's Hospital, Salzburger Landeskliniken (SALK) und Paracelsus Medical University (PMU), 5020 Salzburg, Austria
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18
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Del Rio R, Serrano RG, Gomez E, Martinez JC, Edward MA, Santos RA, Diaz KS, Cohen-Cory S. Cell-autonomous and differential endocannabinoid signaling impacts the development of presynaptic retinal ganglion cell axon connectivity in vivo. Front Synaptic Neurosci 2023; 15:1176864. [PMID: 37252636 PMCID: PMC10213524 DOI: 10.3389/fnsyn.2023.1176864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023] Open
Abstract
Cannabis exposure during gestation evokes significant molecular modifications to neurodevelopmental programs leading to neurophysiological and behavioral abnormalities in humans. The main neuronal receptor for Δ9-tetrahydrocannabinol (THC) is the type-1 cannabinoid receptor CB1R, one of the most abundant G-protein-coupled receptors in the nervous system. While THC is the major psychoactive phytocannabinoid, endocannabinoids (eCBs) are the endogenous ligands of CB1R and are known to act as retrograde messengers to modulate synaptic plasticity at different time scales in the adult brain. Accumulating evidence indicates that eCB signaling through activation of CB1R plays a central role in neural development. During development, most CB1R localized to axons of projection neurons, and in mice eCB signaling impacts axon fasciculation. Understanding of eCB-mediated structural plasticity during development, however, requires the identification of the precise spatial and temporal dynamics of CB1R-mediated modifications at the level of individual neurons in the intact brain. Here, the cell-autonomous role of CB1R and the effects of CB1R-mediated eCB signaling were investigated using targeted single-cell knockdown and pharmacologic treatments in Xenopus. We imaged axonal arbors of retinal ganglion cells (RGCs) in real time following downregulation of CB1R via morpholino (MO) knockdown. We also analyzed RGC axons with altered eCB signaling following treatment with URB597, a selective inhibitor of the enzyme that degrades Anandamide (AEA), or JZL184, an inhibitor of the enzyme that blocks 2-Arachidonoylglycerol (2-AG) hydrolysis, at two distinct stages of retinotectal development. Our results demonstrate that CB1R knockdown impacts RGC axon branching at their target and that differential 2-AG and AEA-mediated eCB signaling contributes to presynaptic structural connectivity at the time that axons terminate and when retinotectal synaptic connections are made. Altering CB1R levels through CB1R MO knockdown similarly impacted dendritic morphology of tectal neurons, thus supporting both pre- and postsynaptic cell-autonomous roles for CB1R-mediated eCB signaling.
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19
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Feller B, Fallon A, Luo W, Nguyen PT, Shlaifer I, Lee AK, Chofflet N, Yi N, Khaled H, Karkout S, Bourgault S, Durcan TM, Takahashi H. α-Synuclein Preformed Fibrils Bind to β-Neurexins and Impair β-Neurexin-Mediated Presynaptic Organization. Cells 2023; 12:cells12071083. [PMID: 37048156 PMCID: PMC10093570 DOI: 10.3390/cells12071083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023] Open
Abstract
Synucleinopathies form a group of neurodegenerative diseases defined by the misfolding and aggregation of α-synuclein (α-syn). Abnormal accumulation and spreading of α-syn aggregates lead to synapse dysfunction and neuronal cell death. Yet, little is known about the synaptic mechanisms underlying the α-syn pathology. Here we identified β-isoforms of neurexins (β-NRXs) as presynaptic organizing proteins that interact with α-syn preformed fibrils (α-syn PFFs), toxic α-syn aggregates, but not α-syn monomers. Our cell surface protein binding assays and surface plasmon resonance assays reveal that α-syn PFFs bind directly to β-NRXs through their N-terminal histidine-rich domain (HRD) at the nanomolar range (KD: ~500 nM monomer equivalent). Furthermore, our artificial synapse formation assays show that α-syn PFFs diminish excitatory and inhibitory presynaptic organization induced by a specific isoform of neuroligin 1 that binds only β-NRXs, but not α-isoforms of neurexins. Thus, our data suggest that α-syn PFFs interact with β-NRXs to inhibit β-NRX-mediated presynaptic organization, providing novel molecular insight into how α-syn PFFs induce synaptic pathology in synucleinopathies such as Parkinson’s disease and dementia with Lewy bodies.
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Affiliation(s)
- Benjamin Feller
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Aurélie Fallon
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Wen Luo
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Phuong Trang Nguyen
- Department of Chemistry, Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada
| | - Irina Shlaifer
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Nicolas Chofflet
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Nayoung Yi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Samer Karkout
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
| | - Steve Bourgault
- Department of Chemistry, Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada
| | - Thomas M. Durcan
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada
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20
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Lee AK, Yi N, Khaled H, Feller B, Takahashi H. SorCS1 inhibits amyloid-β binding to neurexin and rescues amyloid-β-induced synaptic pathology. Life Sci Alliance 2023; 6:e202201681. [PMID: 36697254 PMCID: PMC9880023 DOI: 10.26508/lsa.202201681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Amyloid-β oligomers (AβOs), toxic peptide aggregates found in Alzheimer's disease, cause synapse pathology. AβOs interact with neurexins (NRXs), key synaptic organizers, and this interaction dampens normal trafficking and function of NRXs. Axonal trafficking of NRX is in part regulated by its interaction with SorCS1, a protein sorting receptor, but the impact of SorCS1 regulation of NRXs in Aβ pathology was previously unstudied. Here, we show competition between the SorCS1 ectodomain and AβOs for β-NRX binding and rescue effects of the SorCS1b isoform on AβO-induced synaptic pathology. Like AβOs, the SorCS1 ectodomain binds to NRX1β through the histidine-rich domain of NRX1β, and the SorCS1 ectodomain and AβOs compete for NRX1β binding. In cultured hippocampal neurons, SorCS1b colocalizes with NRX1β on the axon surface, and axonal expression of SorCS1b rescues AβO-induced impairment of NRX-mediated presynaptic organization and presynaptic vesicle recycling and AβO-induced structural defects in excitatory synapses. Thus, our data suggest a role for SorCS1 in the rescue of AβO-induced NRX dysfunction and synaptic pathology, providing the basis for a novel potential therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Nayoung Yi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Benjamin Feller
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
- Division of Experimental Medicine, McGill University, Montreal, Canada
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21
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Haile MT, Khoja S, de Carvalho G, Hunt RF, Chen LY. Conditional deletion of Neurexin-2 alters neuronal network activity in hippocampal circuitries and leads to spontaneous seizures. Transl Psychiatry 2023; 13:97. [PMID: 36941261 PMCID: PMC10027846 DOI: 10.1038/s41398-023-02394-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 03/23/2023] Open
Abstract
Neurexins (Nrxns) have been extensively studied for their role in synapse organization and have been linked to many neuropsychiatric disorders, including autism spectrum disorder (ASD), and epilepsy. However, no studies have provided direct evidence that Nrxns may be the key regulator in the shared pathogenesis of these conditions largely due to complexities among Nrxns and their non-canonical functions in different synapses. Recent studies identified NRXN2 mutations in ASD and epilepsy, but little is known about Nrxn2's role in a circuit-specific manner. Here, we report that conditional deletion of Nrxn2 from the hippocampus and cortex (Nrxn2 cKO) results in behavioral abnormalities, including reduced social preference and increased nestlet shredding behavior. Electrophysiological recordings identified an overall increase in hippocampal CA3→CA1 network activity in Nrxn2 cKO mice. Using intracranial electroencephalogram recordings, we observed unprovoked spontaneous reoccurring electrographic and behavioral seizures in Nrxn2 cKO mice. This study provides the first evidence that conditional deletion of Nrxn2 induces increased network activity that manifests into spontaneous recurrent seizures and behavioral impairments.
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Affiliation(s)
- Mulatwa T Haile
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Sheraz Khoja
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Gregory de Carvalho
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Lulu Y Chen
- Department of Anatomy & Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA.
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22
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Lin PY, Chen LY, Jiang M, Trotter JH, Seigneur E, Südhof TC. Neurexin-2: An inhibitory neurexin that restricts excitatory synapse formation in the hippocampus. SCIENCE ADVANCES 2023; 9:eadd8856. [PMID: 36608123 PMCID: PMC9821874 DOI: 10.1126/sciadv.add8856] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
Neurexins are widely thought to promote synapse formation and to organize synapse properties. Here we found that in contrast to neurexin-1 and neurexin-3, neurexin-2 unexpectedly restricts synapse formation. In the hippocampus, constitutive or neuron-specific deletions of neurexin-2 nearly doubled the strength of excitatory CA3➔CA1 region synaptic connections and markedly increased their release probability. No effect on inhibitory synapses was detected. Stochastic optical reconstruction microscopy (STORM) superresolution microscopy revealed that the neuron-specific neurexin-2 deletion elevated the density of excitatory CA1 region synapses nearly twofold. Moreover, hippocampal neurexin-2 deletions also increased synaptic connectivity in the CA1 region when induced in mature mice and impaired the cognitive flexibility of spatial memory. Thus, neurexin-2 controls the dynamics of hippocampal synaptic circuits by repressing synapse assembly throughout life, a restrictive function that markedly differs from that of neurexin-1 and neurexin-3 and of other synaptic adhesion molecules, suggesting that neurexins evolutionarily diverged into opposing pro- and antisynaptogenic organizers.
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Affiliation(s)
- Pei-Yi Lin
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
| | - Lulu Y. Chen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
| | - Man Jiang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
| | - Justin H. Trotter
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
| | - Erica Seigneur
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Dr., Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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23
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Khoja S, Haile MT, Chen LY. Advances in neurexin studies and the emerging role of neurexin-2 in autism spectrum disorder. Front Mol Neurosci 2023; 16:1125087. [PMID: 36923655 PMCID: PMC10009110 DOI: 10.3389/fnmol.2023.1125087] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/08/2023] [Indexed: 03/02/2023] Open
Abstract
Over the past 3 decades, the prevalence of autism spectrum disorder (ASD) has increased globally from 20 to 28 million cases making ASD the fastest-growing developmental disability in the world. Neurexins are a family of presynaptic cell adhesion molecules that have been increasingly implicated in ASD, as evidenced by genetic mutations in the clinical population. Neurexins function as context-dependent specifiers of synapse properties and critical modulators in maintaining the balance between excitatory and inhibitory transmission (E/I balance). Disrupted E/I balance has long been established as a hallmark of ASD making neurexins excellent starting points for understanding the etiology of ASD. Herein we review neurexin mutations that have been discovered in ASD patients. Further, we discuss distinct synaptic mechanisms underlying the aberrant neurotransmission and behavioral deficits observed in different neurexin mouse models, with focus on recent discoveries from the previously overlooked neurexin-2 gene (Nrxn2 in mice and NRXN2 in humans). Hence, the aim of this review is to provide a summary of new synaptic insights into the molecular underpinnings of ASD.
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Affiliation(s)
- Sheraz Khoja
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Mulatwa T Haile
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
| | - Lulu Y Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA, United States
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24
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Uchigashima M, Hayashi Y, Futai K. Regulation of Presynaptic Release Machinery by Cell Adhesion Molecules. ADVANCES IN NEUROBIOLOGY 2023; 33:333-356. [PMID: 37615873 DOI: 10.1007/978-3-031-34229-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The synapse is a highly specialized asymmetric structure that transmits and stores information in the brain. The size of pre- and postsynaptic structures and function is well coordinated at the individual synapse level. For example, large postsynaptic dendritic spines have a larger postsynaptic density with higher α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) number on their surface, while juxtaposing presynaptic terminals have a larger active zone and higher release probability. This indicates that pre- and postsynaptic domains bidirectionally communicate to coordinate assembly of specific molecules on both sides of the synaptic cleft. Cell adhesion molecules (CAMs) that localize at synapses form transsynaptic protein interactions across the synaptic cleft and play important roles in synapse formation and regulation. The extracellular domain of CAMs is essential for specific synapse formation and function. In contrast, the intracellular domain is necessary for binding with synaptic molecules and signal transduction. Therefore, CAMs play an essential role on synapse function and structure. In fact, ample evidence indicates that transsynaptic CAMs instruct and modulate functions at presynaptic sites. This chapter focuses on transsynaptic protein interactions that regulate presynaptic functions emphasizing the role of neuronal CAMs and the intracellular mechanism of their regulation.
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Affiliation(s)
- Motokazu Uchigashima
- Department of Cellular Neuropathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kensuke Futai
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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25
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Reece AS, Hulse GK. European Epidemiological Patterns of Cannabis- and Substance-Related Congenital Neurological Anomalies: Geospatiotemporal and Causal Inferential Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 20:ijerph20010441. [PMID: 36612763 PMCID: PMC9819725 DOI: 10.3390/ijerph20010441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 05/16/2023]
Abstract
Introduction. Of the many congenital anomalies (CAs) recently linked with community cannabis exposure, arguably the most concerning are neurological CAs (NCAs). We therefore conducted a detailed study of this in fourteen European nations. Methods. Congenital anomaly data were from Eurocat. Drug exposure data were from European Monitoring Centre for Drugs and Drug Addiction. Income from World bank. Results. The Netherlands, Spain, France and Bulgaria reported increasing rates of many NCAs. The NCA rate (NCAR) was higher in nations with increasing daily cannabis use when compared to those without (p = 0.0204, minimum E-value (mEV) = 1.35). At bivariate analysis, the mEVs of the following NCAs were significantly cannabis related: severe microcephaly 2.14 × 1013, craniosynostosis 5.27 × 1011, nervous system 4.87 × 1011, eye 2.73 × 107, microphthalmos 4.07 × 106, anencephalus 710.37, hydrocephalus 245.64, spina bifida 14.86 and neural tube defects 13.15. At inverse probability, weighted panel regression terms including cannabis were significantly related to the following series of anomalies: nervous system, anencephalus, severe microcephalus, microphthalmos, neural tube defect and spina bifida from p = 5.09 × 10−8, <2.2 × 10−16, <2.2 × 10−16, 4.84 × 10−11, <2.2 × 10−16 and 9.69 × 10−7. At geospatial regression, this same series of anomalies had terms including cannabis significant from p = 0.0027, 1.53 × 10−7, 3.65 × 10−6, 2.13 × 10−8, 0.0002 and 9.76 × 10−12. 88.0% of 50 E-value estimates and 72.0% of mEVs > 9. This analysis therefore demonstrates both close association of cannabis exposure with multiple NCAs across space-time and also fulfills the quantitative criteria of causal inferential analysis. Conclusions. Nine NCARs on bivariate and six NCARs on multivariable regression were cannabis related and fulfilled quantitative epidemiological criteria for causality and are consistent with other series. Particular concerns relate to exponential dose−response effects demonstrated in the laboratory and epidemiological studies. Great caution with community cannabinoid penetration is warranted. Data indicate that cannabis is a significant environmental teratogen and thus imply that cannabinoids should be regulated similarly to the manner in which all other important genotoxins are carefully controlled by communities for their self-sustaining longevity and the protection of generations yet to come.
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Affiliation(s)
- Albert Stuart Reece
- Division of Psychiatry, University of Western Australia, Crawley, WA 6009, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia
- Correspondence: ; Tel.: +61-7-3844-4000; Fax: +61-7-3844-4015
| | - Gary Kenneth Hulse
- Division of Psychiatry, University of Western Australia, Crawley, WA 6009, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia
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26
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Boxer EE, Aoto J. Neurexins and their ligands at inhibitory synapses. Front Synaptic Neurosci 2022; 14:1087238. [PMID: 36618530 PMCID: PMC9812575 DOI: 10.3389/fnsyn.2022.1087238] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/24/2022] [Indexed: 12/24/2022] Open
Abstract
Since the discovery of neurexins (Nrxns) as essential and evolutionarily conserved synaptic adhesion molecules, focus has largely centered on their functional contributions to glutamatergic synapses. Recently, significant advances to our understanding of neurexin function at GABAergic synapses have revealed that neurexins can play pleiotropic roles in regulating inhibitory synapse maintenance and function in a brain-region and synapse-specific manner. GABAergic neurons are incredibly diverse, exhibiting distinct synaptic properties, sites of innervation, neuromodulation, and plasticity. Different classes of GABAergic neurons often express distinct repertoires of Nrxn isoforms that exhibit differential alternative exon usage. Further, Nrxn ligands can be differentially expressed and can display synapse-specific localization patterns, which may contribute to the formation of a complex trans-synaptic molecular code that establishes the properties of inhibitory synapse function and properties of local circuitry. In this review, we will discuss how Nrxns and their ligands sculpt synaptic inhibition in a brain-region, cell-type and synapse-specific manner.
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Affiliation(s)
| | - Jason Aoto
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Denver, CO, United States
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27
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Tang C, Jin Y, Wang H. The biological alterations of synapse/synapse formation in sepsis-associated encephalopathy. Front Synaptic Neurosci 2022; 14:1054605. [PMID: 36530954 PMCID: PMC9755596 DOI: 10.3389/fnsyn.2022.1054605] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/18/2022] [Indexed: 06/12/2024] Open
Abstract
Sepsis-associated encephalopathy (SAE) is a common complication caused by sepsis, and is responsible for increased mortality and poor outcomes in septic patients. Neurological dysfunction is one of the main manifestations of SAE patients. Patients may still have long-term cognitive impairment after hospital discharge, and the underlying mechanism is still unclear. Here, we first outline the pathophysiological changes of SAE, including neuroinflammation, glial activation, and blood-brain barrier (BBB) breakdown. Synapse dysfunction is one of the main contributors leading to neurological impairment. Therefore, we summarized SAE-induced synaptic dysfunction, such as synaptic plasticity inhibition, neurotransmitter imbalance, and synapses loss. Finally, we discuss the alterations in the synapse, synapse formation, and mediators associated with synapse formation during SAE. In this review, we focus on the changes in synapse/synapse formation caused by SAE, which can further understand the synaptic dysfunction associated with neurological impairment in SAE and provide important insights for exploring appropriate therapeutic targets of SAE.
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Affiliation(s)
| | | | - Huan Wang
- College of Life and Health, Dalian University, Dalian, China
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28
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Neurexin-β Mediates the Synaptogenic Activity of Amyloid Precursor Protein. J Neurosci 2022; 42:8936-8947. [PMID: 36261284 PMCID: PMC9732828 DOI: 10.1523/jneurosci.0511-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 09/13/2022] [Accepted: 10/12/2022] [Indexed: 01/05/2023] Open
Abstract
In addition to its role in Alzheimer's disease, amyloid precursor protein (APP) has physiological roles in synapse development and function. APP induces presynaptic differentiation when presented to axons, but the mechanism is unknown. Here we show that APP binds neurexin to mediate this synaptogenic activity. APP specifically binds β not α neurexins modulated by splice site 4. Binding to neurexin heparan sulfate glycan and LNS protein domains is required for high-affinity interaction and for full-length APP to recruit axonal neurexin. The synaptogenic activity of APP is abolished by triple knockdown of neurexins in hippocampal neurons pooled from male and female rats. Based on these and previous results, our model is that a dendritic-axonal trans dimer of full-length APP binds to axonal neurexin-β to promote synaptic differentiation and function. Furthermore, soluble sAPPs also bind neurexin-β and inhibit its interaction with neuroligin-1, raising the possibility that disruption of neurexin function by altered levels of full-length APP and its cleavage products may contribute to early synaptic deficits in Alzheimer's disease.SIGNIFICANCE STATEMENT The prevailing model for the basis of Alzheimer's disease is the amyloid cascade triggered by altered cleavage of amyloid precursor protein (APP). APP also has physiological roles at the synapse, but the molecular basis for its synaptic functions is not well understood. Here, we show that APP binds the presynaptic organizing protein neurexin-β and that neurexin is essential for the synaptogenic activity of APP. Furthermore, soluble APP forms generated by APP cleavage also bind neurexin-β and can block interaction with transmembrane synaptogenic ligands of neurexin. These findings reveal a role for neurexin-APP interaction in synapse development and raise the possibility that disruptions of neurexin function may contribute to synaptic and cognitive deficits in the critical early stage of Alzheimer's disease.
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29
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Cannabis Use in Autism: Reasons for Concern about Risk for Psychosis. Healthcare (Basel) 2022; 10:healthcare10081553. [PMID: 36011210 PMCID: PMC9407973 DOI: 10.3390/healthcare10081553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/31/2022] [Accepted: 08/14/2022] [Indexed: 01/09/2023] Open
Abstract
Being particularly vulnerable to the pro-psychotic effects of cannabinoid exposure, autism spectrum individuals present with an increased risk of psychosis, which may be passed on to their own children. More specifically, cannabis exposure among autism spectrum individuals seems to exert disruptive epigenetic effects that can be intergenerationally inherited in brain areas which play a critical role in schizophrenia pathophysiology. Additionally, because of such cannabinoid-induced epigenetic effects, autism candidate genes present with bivalent chromatin markings which make them more vulnerable to subsequent disruption, possibly leading to psychosis onset later in life. Thus, findings support a developmental trajectory between autism and psychosis, as per endocannabinoid system modulation. However, such evidence has not received the attention it deserves.
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30
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Li H, Guo R, Guan Y, Li J, Wang Y. Modulation of Trans-Synaptic Neurexin-Neuroligin Interaction in Pathological Pain. Cells 2022; 11:cells11121940. [PMID: 35741069 PMCID: PMC9222181 DOI: 10.3390/cells11121940] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 11/16/2022] Open
Abstract
Synapses serve as the interface for the transmission of information between neurons in the central nervous system. The structural and functional characteristics of synapses are highly dynamic, exhibiting extensive plasticity that is shaped by neural activity and regulated primarily by trans-synaptic cell-adhesion molecules (CAMs). Prototypical trans-synaptic CAMs, such as neurexins (Nrxs) and neuroligins (Nlgs), directly regulate the assembly of presynaptic and postsynaptic molecules, including synaptic vesicles, active zone proteins, and receptors. Therefore, the trans-synaptic adhesion mechanisms mediated by Nrx-Nlg interaction can contribute to a range of synaptopathies in the context of pathological pain and other neurological disorders. The present review provides an overview of the current understanding of the roles of Nrx-Nlg interaction in the regulation of trans-synaptic connections, with a specific focus on Nrx and Nlg structures, the dynamic shaping of synaptic function, and the dysregulation of Nrx-Nlg in pathological pain. Additionally, we discuss a range of proteins capable of modulating Nrx-Nlg interactions at the synaptic cleft, with the objective of providing a foundation to guide the future development of novel therapeutic agents for managing pathological pain.
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Affiliation(s)
- Huili Li
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China;
| | - Ruijuan Guo
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100030, China;
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
| | - Junfa Li
- Department of Neurobiology, Capital Medical University, Beijing 100069, China;
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China;
- Correspondence: ; Tel.: +86-10-85231463
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31
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Xu Y, Wang ML, Tao H, Geng C, Guo F, Hu B, Wang R, Hou XY. ErbB4 in parvalbumin-positive interneurons mediates proactive interference in olfactory associative reversal learning. Neuropsychopharmacology 2022; 47:1292-1303. [PMID: 34707248 PMCID: PMC9117204 DOI: 10.1038/s41386-021-01205-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 09/04/2021] [Accepted: 10/02/2021] [Indexed: 11/09/2022]
Abstract
Consolidated memories influence later learning and cognitive processes when new information is overlapped with previous events. To reveal which cellular and molecular factors are associated with this proactive interference, we challenged mice with odor-reward associative learning followed by a reversal-learning task. The results showed that genetical ablation of ErbB4 in parvalbumin (PV)-positive interneurons improved performance in reversal-learning phase, with no alteration in learning phase, supporting that PV interneuron ErbB4 is required for proactive interference. Mechanistically, olfactory learning promoted PV interneuron excitatory synaptic plasticity and direct binding of ErbB4 with presynaptic Neurexin1β (NRXN1β) and postsynaptic scaffold PSD-95 in the prefrontal cortex. Interrupting ErbB4-NRXN1β interaction impaired network activity-driven excitatory inputs and excitatory synaptic transmission onto PV interneurons. Neuronal activity-induced ErbB4-PSD-95 association facilitated transsynaptic binding of ErbB4-NRXN1β and excitatory synapse formation in ErbB4-positive interneurons. Furthermore, ErbB4-NRXN1β binding was responsible for the activity-regulated activation of ErbB4 and extracellular signal-regulated kinase (ERK) 1/2 in PV interneurons, as well as synaptic plasticity-related expression of brain-derived neurotrophic factor (BDNF). Correlatedly, blocking ErbB4-NRXN1β coupling in the medial prefrontal cortex of adult mice facilitated reversal learning of an olfactory associative task. These findings provide novel insight into the physiological role of PV interneuron ErbB4 signaling in cognitive processes and reveal an associative learning-related transsynaptic NRXN1β-ErbB4-PSD-95 complex that affects the ERK1/2-BDNF pathway and underlies local inhibitory circuit plasticity and proactive interference.
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Affiliation(s)
- Yan Xu
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Meng-Lin Wang
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Hui Tao
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China ,grid.254147.10000 0000 9776 7793State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu 211198 China
| | - Chi Geng
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Feng Guo
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Bin Hu
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Ran Wang
- grid.417303.20000 0000 9927 0537Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu 221004 China
| | - Xiao-Yu Hou
- Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China. .,State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
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32
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Sciacca M, Marino L, Vitaliti G, Falsaperla R, Marino S. NRXN1 Deletion in Two Twins’ Genotype and Phenotype: A Clinical Case and Literature Review. CHILDREN 2022; 9:children9050698. [PMID: 35626875 PMCID: PMC9139251 DOI: 10.3390/children9050698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/29/2022] [Accepted: 05/06/2022] [Indexed: 11/21/2022]
Abstract
In the literature, deletions in the 2p16.3 region of the neurexin gene (NRXN1) are associated with cognitive impairment, and other neuropsychiatric disorders, such as schizophrenia, autism, and Pitt–Hopkins-like syndrome 2. In this paper, we present twins with deletion 2p16.3 of the NRXN1 gene using a comparative genomic hybridization array. The two children had a dual diagnosis consisting of mild cognitive impairment and neurodevelopmental delay. Furthermore, they showed a dysmorphic phenotype characterized by facio-cranial disproportion, turricephalus, macrocrania, macrosomia, strabismus, and abnormal conformation of both auricles with low implantation. The genetic analysis of the family members showed the presence, in the father’s genetic test, of a microdeletion of the short arm of chromosome 2, in the 2p16.3 region. Our case report can expand the knowledge on the genotype–phenotype association in carriers of 2p16.3 deletion and for genetic counseling that could help in the prevention and eventual treatment of this genetic condition. Newborn carriers should undergo neurobehavioral follow-ups for timely detection of warning signs.
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Affiliation(s)
- Monica Sciacca
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95100 Catania, Italy; (M.S.); (L.M.)
| | - Lidia Marino
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, 95100 Catania, Italy; (M.S.); (L.M.)
| | - Giovanna Vitaliti
- Section of Pediatrics, Department of Medical Sciences, Sant’Anna University Hospital, University of Ferrara, 44121 Ferrara, Italy
- Correspondence:
| | - Raffaele Falsaperla
- Neonatal Intensive Care Unit, AOU “Policlinico”, PO “San Marco”, University of Catania, 95100 Catania, Italy;
- Unit of Pediatrics and Pediatric Emergency, AOU “Policlinico”, PO “San Marco”, University of Catania, 95100 Catania, Italy;
| | - Silvia Marino
- Unit of Pediatrics and Pediatric Emergency, AOU “Policlinico”, PO “San Marco”, University of Catania, 95100 Catania, Italy;
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Colizzi M, Bortoletto R, Costa R, Bhattacharyya S, Balestrieri M. The Autism-Psychosis Continuum Conundrum: Exploring the Role of the Endocannabinoid System. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:5616. [PMID: 35565034 PMCID: PMC9105053 DOI: 10.3390/ijerph19095616] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/01/2022] [Accepted: 05/03/2022] [Indexed: 02/07/2023]
Abstract
Evidence indicates shared physiopathological mechanisms between autism and psychosis. In this regard, the endocannabinoid system has been suggested to modulate neural circuits during the early stage of neurodevelopment, with implications for both autism and psychosis. Nevertheless, such potential common markers of disease have been investigated in both autism and psychosis spectrum disorders, without considering the conundrum of differentiating the two groups of conditions in terms of diagnosis and treatment. Here, we systematically review all human and animal studies examining the endocannabinoid system and its biobehavioral correlates in the association between autism and psychosis. Studies indicate overlapping biobehavioral aberrancies between autism and schizophrenia, subject to correction by modulation of the endocannabinoid system. In addition, common cannabinoid-based pharmacological strategies have been identified, exerting epigenetic effects across genes controlling neural mechanisms shared between autism and schizophrenia. Interestingly, a developmental and transgenerational trajectory between autism and schizophrenia is supported by evidence that exogenous alteration of the endocannabinoid system promotes progression to inheritable psychosis phenotypes in the context of biobehavioral autism vulnerability. However, evidence for a diametral association between autism and psychosis is scant. Several clinical implications follow from evidence of a developmental continuum between autism and psychosis as a function of the endocannabinoid system dysregulation.
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Affiliation(s)
- Marco Colizzi
- Unit of Psychiatry, Department of Medicine (DAME), University of Udine, 33100 Udine, Italy;
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK;
| | - Riccardo Bortoletto
- Child and Adolescent Neuropsychiatry Unit, Maternal-Child Integrated Care Department, Integrated University Hospital of Verona, 37126 Verona, Italy;
| | - Rosalia Costa
- Community Mental Health Team, Friuli Centrale University Health Service (ASUFC), 33057 Palmanova, Italy;
| | - Sagnik Bhattacharyya
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK;
| | - Matteo Balestrieri
- Unit of Psychiatry, Department of Medicine (DAME), University of Udine, 33100 Udine, Italy;
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Uemura T, Suzuki-Kouyama E, Kawase S, Kurihara T, Yasumura M, Yoshida T, Fukai S, Yamazaki M, Fei P, Abe M, Watanabe M, Sakimura K, Mishina M, Tabuchi K. Neurexins play a crucial role in cerebellar granule cell survival by organizing autocrine machinery for neurotrophins. Cell Rep 2022; 39:110624. [PMID: 35385735 DOI: 10.1016/j.celrep.2022.110624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 02/22/2022] [Accepted: 03/15/2022] [Indexed: 01/22/2023] Open
Abstract
Neurexins (NRXNs) are key presynaptic cell adhesion molecules that regulate synapse formation and function via trans-synaptic interaction with postsynaptic ligands. Here, we generate cerebellar granule cell (CGC)-specific Nrxn triple-knockout (TKO) mice for complete deletion of all NRXNs. Unexpectedly, most CGCs die in these mice, and this requirement for NRXNs for cell survival is reproduced in cultured CGCs. The axons of cultured Nrxn TKO CGCs that are not in contact with a postsynaptic structure show defects in the formation of presynaptic protein clusters and in action-potential-induced Ca2+ influxes. These cells also show impaired secretion of depolarization-induced, fluorescence-tagged brain-derived neurotrophic factor (BDNF) from their axons, and the cell-survival defect is rescued by the application of BDNF. These results suggest that CGC survival is maintained by autocrine neurotrophic factors and that NRXNs organize the presynaptic protein clusters and the autocrine neurotrophic-factor secretory machinery independent of contact with postsynaptic ligands.
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Affiliation(s)
- Takeshi Uemura
- Division of Gene Research, Research Center for Advanced Science, Shinshu University, Nagano 390-8621, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; JST CREST, Saitama 332-0012, Japan.
| | - Emi Suzuki-Kouyama
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST CREST, Saitama 332-0012, Japan
| | - Shiori Kawase
- Division of Gene Research, Research Center for Advanced Science, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST CREST, Saitama 332-0012, Japan
| | - Taiga Kurihara
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan
| | - Misato Yasumura
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan; JST PRESTO, Saitama 332-0012, Japan
| | - Shuya Fukai
- JST CREST, Saitama 332-0012, Japan; Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Peng Fei
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan; Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan; Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masayoshi Mishina
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Brain Science Laboratory, Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan
| | - Katsuhiko Tabuchi
- Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST PRESTO, Saitama 332-0012, Japan.
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Abstract
Neurexin-3 is primarily localized in the presynaptic membrane and forms complexes with various ligands located in the postsynaptic membrane. Neurexin-3 has important roles in synapse development and synapse functions. Neurexin-3 mediates excitatory presynaptic differentiation by interacting with leucine-rich-repeat transmembrane neuronal proteins. Meanwhile, neurexin-3 modulates the expression of presynaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors and γ-aminobutyric acid A receptors by interacting with neuroligins at excitatory and inhibitory synapses. Numerous studies have documented the potential contribution of neurexin-3 to neurodegenerative and neuropsychiatric disorders, such as Alzheimer's disease, addiction behaviors, and other diseases, which raises hopes that understanding the mechanisms of neurexin-3 may hold the key to developing new strategies for related illnesses. This review comprehensively covers the literature to provide current knowledge of the structure, function, and clinical role of neurexin-3.
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Cooke J, Molloy CJ, Cáceres ASJ, Dinneen T, Bourgeron T, Murphy D, Gallagher L, Loth E. The Synaptic Gene Study: Design and Methodology to Identify Neurocognitive Markers in Phelan-McDermid Syndrome and NRXN1 Deletions. Front Neurosci 2022; 16:806990. [PMID: 35250452 PMCID: PMC8894872 DOI: 10.3389/fnins.2022.806990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/26/2022] [Indexed: 11/26/2022] Open
Abstract
Synaptic gene conditions, i.e., “synaptopathies,” involve disruption to genes expressed at the synapse and account for between 0.5 and 2% of autism cases. They provide a unique entry point to understanding the molecular and biological mechanisms underpinning autism-related phenotypes. Phelan-McDermid Syndrome (PMS, also known as 22q13 deletion syndrome) and NRXN1 deletions (NRXN1ds) are two synaptopathies associated with autism and related neurodevelopmental disorders (NDDs). PMS often incorporates disruption to the SHANK3 gene, implicated in excitatory postsynaptic scaffolding, whereas the NRXN1 gene encodes neurexin-1, a presynaptic cell adhesion protein; both are implicated in trans-synaptic signaling in the brain. Around 70% of individuals with PMS and 43–70% of those with NRXN1ds receive a diagnosis of autism, suggesting that alterations in synaptic development may play a crucial role in explaining the aetiology of autism. However, a substantial amount of heterogeneity exists between conditions. Most individuals with PMS have moderate to profound intellectual disability (ID), while those with NRXN1ds have no ID to severe ID. Speech abnormalities are common to both, although appear more severe in PMS. Very little is currently known about the neurocognitive underpinnings of phenotypic presentations in PMS and NRXN1ds. The Synaptic Gene (SynaG) study adopts a gene-first approach and comprehensively assesses these two syndromic forms of autism. The study compliments preclinical efforts within AIMS-2-TRIALS focused on SHANK3 and NRXN1. The aims of the study are to (1) establish the frequency of autism diagnosis and features in individuals with PMS and NRXN1ds, (2) to compare the clinical profile of PMS, NRXN1ds, and individuals with ‘idiopathic’ autism (iASD), (3) to identify mechanistic biomarkers that may account for autistic features and/or heterogeneity in clinical profiles, and (4) investigate the impact of second or multiple genetic hits on heterogeneity in clinical profiles. In the current paper we describe our methodology for phenotyping the sample and our planned comparisons, with information on the necessary adaptations made during the global COVID-19 pandemic. We also describe the demographics of the data collected thus far, including 25 PMS, 36 NRXN1ds, 33 iASD, and 52 NTD participants, and present an interim analysis of autistic features and adaptive functioning.
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Affiliation(s)
- Jennifer Cooke
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
- *Correspondence: Jennifer Cooke,
| | - Ciara J. Molloy
- Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Antonia San José Cáceres
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
- Fundación para la Investigación Biomédica del Hospital General Universitario Gregorio Marañón, Madrid, Spain
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Madrid, Spain
| | - Thomas Dinneen
- Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | | | - Declan Murphy
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
| | - Louise Gallagher
- Department of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Eva Loth
- Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
- Eva Loth,
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Ferdos S, Brockhaus J, Missler M, Rohlmann A. Deletion of β-Neurexins in Mice Alters the Distribution of Dense-Core Vesicles in Presynapses of Hippocampal and Cerebellar Neurons. Front Neuroanat 2022; 15:757017. [PMID: 35173587 PMCID: PMC8841415 DOI: 10.3389/fnana.2021.757017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022] Open
Abstract
Communication between neurons through synapses includes the release of neurotransmitter-containing synaptic vesicles (SVs) and of neuromodulator-containing dense-core vesicles (DCVs). Neurexins (Nrxns), a polymorphic family of cell surface molecules encoded by three genes in vertebrates (Nrxn1–3), have been proposed as essential presynaptic organizers and as candidates for cell type-specific or even synapse-specific regulation of synaptic vesicle exocytosis. However, it remains unknown whether Nrxns also regulate DCVs. Here, we report that at least β-neurexins (β-Nrxns), an extracellularly smaller Nrxn variant, are involved in the distribution of presynaptic DCVs. We found that conditional deletion of all three β-Nrxn isoforms in mice by lentivirus-mediated Cre recombinase expression in primary hippocampal neurons reduces the number of ultrastructurally identified DCVs in presynaptic boutons. Consistently, colabeling against marker proteins revealed a diminished population of chromogranin A- (ChrgA-) positive DCVs in synapses and axons of β-Nrxn-deficient neurons. Moreover, we validated the impaired DCV distribution in cerebellar brain tissue from constitutive β-Nrxn knockout (β-TKO) mice, where DCVs are normally abundant and β-Nrxn isoforms are prominently expressed. Finally, we observed that the ultrastructure and marker proteins of the Golgi apparatus, responsible for packaging neuropeptides into DCVs, seem unchanged. In conclusion, based on the validation from the two deletion strategies in conditional and constitutive KO mice, two neuronal populations from the hippocampus and cerebellum, and two experimental protocols in cultured neurons and in the brain tissue, this study presented morphological evidence that the number of DCVs at synapses is altered in the absence of β-Nrxns. Our results therefore point to an unexpected contribution of β-Nrxns to the organization of neuropeptide and neuromodulator function, in addition to their more established role in synaptic vesicle release.
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38
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Garrido D, Beretta S, Grabrucker S, Bauer HF, Bayer D, Sala C, Verpelli C, Roselli F, Bockmann J, Proepper C, Catanese A, Boeckers TM. Shank2/3 double knockout-based screening of cortical subregions links the retrosplenial area to the loss of social memory in autism spectrum disorders. Mol Psychiatry 2022; 27:4994-5006. [PMID: 36100669 PMCID: PMC9763120 DOI: 10.1038/s41380-022-01756-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 08/15/2022] [Accepted: 08/15/2022] [Indexed: 01/19/2023]
Abstract
Members of the Shank protein family are master scaffolds of the postsynaptic architecture and mutations within the SHANK genes are causally associated with autism spectrum disorders (ASDs). We generated a Shank2-Shank3 double knockout mouse that is showing severe autism related core symptoms, as well as a broad spectrum of comorbidities. We exploited this animal model to identify cortical brain areas linked to specific autistic traits by locally deleting Shank2 and Shank3 simultaneously. Our screening of 10 cortical subregions revealed that a Shank2/3 deletion within the retrosplenial area severely impairs social memory, a core symptom of ASD. Notably, DREADD-mediated neuronal activation could rescue the social impairment triggered by Shank2/3 depletion. Data indicate that the retrosplenial area has to be added to the list of defined brain regions that contribute to the spectrum of behavioural alterations seen in ASDs.
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Affiliation(s)
- Débora Garrido
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany ,grid.6582.90000 0004 1936 9748International Graduate School, Ulm University, 89081 Ulm, Germany
| | - Stefania Beretta
- grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
| | - Stefanie Grabrucker
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Helen Friedericke Bauer
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany ,grid.6582.90000 0004 1936 9748International Graduate School, Ulm University, 89081 Ulm, Germany
| | - David Bayer
- grid.6582.90000 0004 1936 9748International Graduate School, Ulm University, 89081 Ulm, Germany ,grid.6582.90000 0004 1936 9748Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Carlo Sala
- grid.418879.b0000 0004 1758 9800CNR, Institute for Neuroscience, Milano, Italy
| | - Chiara Verpelli
- grid.418879.b0000 0004 1758 9800CNR, Institute for Neuroscience, Milano, Italy
| | - Francesco Roselli
- grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany ,grid.6582.90000 0004 1936 9748Department of Neurology, Ulm University, 89081 Ulm, Germany
| | - Juergen Bockmann
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Christian Proepper
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Alberto Catanese
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
| | - Tobias M. Boeckers
- grid.6582.90000 0004 1936 9748Institute of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany ,grid.424247.30000 0004 0438 0426German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
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39
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Riemersma IW, Havekes R, Kas MJH. Spatial and Temporal Gene Function Studies in Rodents: Towards Gene-Based Therapies for Autism Spectrum Disorder. Genes (Basel) 2021; 13:28. [PMID: 35052369 PMCID: PMC8774890 DOI: 10.3390/genes13010028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/06/2021] [Accepted: 12/20/2021] [Indexed: 12/26/2022] Open
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that is characterized by differences in social interaction, repetitive behaviors, restricted interests, and sensory differences beginning early in life. Especially sensory symptoms are highly correlated with the severity of other behavioral differences. ASD is a highly heterogeneous condition on multiple levels, including clinical presentation, genetics, and developmental trajectories. Over a thousand genes have been implicated in ASD. This has facilitated the generation of more than two hundred genetic mouse models that are contributing to understanding the biological underpinnings of ASD. Since the first symptoms already arise during early life, it is especially important to identify both spatial and temporal gene functions in relation to the ASD phenotype. To further decompose the heterogeneity, ASD-related genes can be divided into different subgroups based on common functions, such as genes involved in synaptic function. Furthermore, finding common biological processes that are modulated by this subgroup of genes is essential for possible patient stratification and the development of personalized early treatments. Here, we review the current knowledge on behavioral rodent models of synaptic dysfunction by focusing on behavioral phenotypes, spatial and temporal gene function, and molecular targets that could lead to new targeted gene-based therapy.
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Affiliation(s)
| | | | - Martien J. H. Kas
- Groningen Institute for Evolutionary Life Sciences, Neurobiology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands; (I.W.R.); (R.H.)
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Mehta A, Shirai Y, Kouyama-Suzuki E, Zhou M, Yoshizawa T, Yanagawa T, Mori T, Tabuchi K. IQSEC2 Deficiency Results in Abnormal Social Behaviors Relevant to Autism by Affecting Functions of Neural Circuits in the Medial Prefrontal Cortex. Cells 2021; 10:2724. [PMID: 34685703 PMCID: PMC8534507 DOI: 10.3390/cells10102724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/28/2022] Open
Abstract
IQSEC2 is a guanine nucleotide exchange factor (GEF) for ADP-ribosylation factor 6 (Arf6), of which protein is exclusively localized to the postsynaptic density of the excitatory synapse. Human genome studies have revealed that the IQSEC2 gene is associated with X-linked neurodevelopmental disorders, such as intellectual disability (ID), epilepsy, and autism. In this study, we examined the behavior and synapse function in IQSEC2 knockout (KO) mice that we generated using CRIPSR/Cas9-mediated genome editing to solve the relevance between IQSEC2 deficiency and the pathophysiology of neurodevelopmental disorders. IQSEC2 KO mice exhibited autistic behaviors, such as overgrooming and social deficits. We identified that up-regulation of c-Fos expression in the medial prefrontal cortex (mPFC) induced by social stimulation was significantly attenuated in IQSEC2 KO mice. Whole cell electrophysiological recording identified that synaptic transmissions mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), N-methyl-D-aspartate receptor (NMDAR), and γ-aminobutyric acid receptor (GABAR) were significantly decreased in pyramidal neurons in layer 5 of the mPFC in IQSEC2 KO mice. Reexpression of IQSEC2 isoform 1 in the mPFC of IQSEC2 KO mice using adeno-associated virus (AAV) rescued both synaptic and social deficits, suggesting that impaired synaptic function in the mPFC is responsible for social deficits in IQSEC2 KO mice.
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Affiliation(s)
- Anuradha Mehta
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
| | - Emi Kouyama-Suzuki
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
| | - Mengyun Zhou
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
| | - Takahiro Yoshizawa
- Research Center for Advanced Science and Technology, Shinshu University, Matsumoto 390-8621, Japan;
| | - Toru Yanagawa
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba 305-8575, Japan;
| | - Takuma Mori
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
- Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto 390-8621, Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan; (A.M.); (Y.S.); (E.K.-S.); (M.Z.); (T.M.)
- Department of NeuroHealth Innovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto 390-8621, Japan
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41
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Borgmeyer M, Coman C, Has C, Schött HF, Li T, Westhoff P, Cheung YFH, Hoffmann N, Yuanxiang P, Behnisch T, Gomes GM, Dumenieu M, Schweizer M, Chocholoušková M, Holčapek M, Mikhaylova M, Kreutz MR, Ahrends R. Multiomics of synaptic junctions reveals altered lipid metabolism and signaling following environmental enrichment. Cell Rep 2021; 37:109797. [PMID: 34610315 DOI: 10.1016/j.celrep.2021.109797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 04/12/2021] [Accepted: 09/15/2021] [Indexed: 12/30/2022] Open
Abstract
Membrane lipids and their metabolism have key functions in neurotransmission. Here we provide a quantitative lipid inventory of mouse and rat synaptic junctions. To this end, we developed a multiomics extraction and analysis workflow to probe the interplay of proteins and lipids in synaptic signal transduction from the same sample. Based on this workflow, we generate hypotheses about novel mechanisms underlying complex changes in synaptic connectivity elicited by environmental stimuli. As a proof of principle, this approach reveals that in mice exposed to an enriched environment, reduced endocannabinoid synthesis and signaling is linked to increased surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) in a subset of Cannabinoid-receptor 1 positive synapses. This mechanism regulates synaptic strength in an input-specific manner. Thus, we establish a compartment-specific multiomics workflow that is suitable to extract information from complex lipid and protein networks involved in synaptic function and plasticity.
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Affiliation(s)
- Maximilian Borgmeyer
- Leibniz Group 'Dendritic Organelles and Synaptic Function,' University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany; RG Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Cristina Coman
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany; Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Wien, Austria
| | - Canan Has
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - Hans-Frieder Schött
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - Tingting Li
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - Philipp Westhoff
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - Yam F H Cheung
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - Nils Hoffmann
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany
| | - PingAn Yuanxiang
- RG Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Thomas Behnisch
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Guilherme M Gomes
- RG Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Mael Dumenieu
- RG Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Michaela Schweizer
- Morphology and Electron Microscopy, University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany
| | - Michaela Chocholoušková
- University of Pardubice, Department of Analytical Chemistry, CZ-532 10 Pardubice, Czech Republic
| | - Michal Holčapek
- University of Pardubice, Department of Analytical Chemistry, CZ-532 10 Pardubice, Czech Republic
| | - Marina Mikhaylova
- Emmy Noether Group 'Neuronal Protein Transport,' University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany; AG Optobiology, Institute for Biology, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Michael R Kreutz
- Leibniz Group 'Dendritic Organelles and Synaptic Function,' University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany; RG Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany; German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, 30120 Magdeburg, Germany.
| | - Robert Ahrends
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., 44227 Dortmund, Germany; Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, 1090 Wien, Austria.
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Balezina OP, Tarasova EO, Gaydukov AE. Noncanonical Activity of Endocannabinoids and Their Receptors in Central and Peripheral Synapses. BIOCHEMISTRY (MOSCOW) 2021; 86:818-832. [PMID: 34284706 DOI: 10.1134/s0006297921070038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review focuses on new aspects of endocannabinoid functions and mechanisms of activity in central and peripheral synapses, different from the general viewpoint that endocannabinoids are retrograde signaling molecules, which inhibit neurotransmitter release by activating specific presynaptic endocannabinoid receptors CB1 and CB2. Biased agonism of the endogenous and synthetic cannabinoids as well as ability of the CB-receptors to couple not only with classical Gi-proteins, but also with Gs- and Gq-proteins and, moreover, with β-arrestins (thereby triggering additional signaling pathways in synapses) are described here in detail. Examples of noncanonical tonic activity of endocannabinoids and their receptors and their role in synaptic function are also presented. The role of endocannabinoids in short-term and long-term potentiation of neurotransmitter release in central synapses and their facilitating effect on quantal size and other parameters of acetylcholine release in mammalian neuromuscular junctions are highlighted in this review. In conclusion, it is stated that the endocannabinoid system has a wider range of various multidirectional modulating effects (both potentiating and inhibiting) on neurotransmitter release than initially recognized. Re-evaluation of the functions of endocannabinoid system with consideration of its noncanonical features will lead to better understanding of its role in the normal and pathological functioning of the nervous system and other systems of the body, which has an enormous practical value.
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Affiliation(s)
- Olga P Balezina
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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Südhof TC. The cell biology of synapse formation. J Cell Biol 2021; 220:e202103052. [PMID: 34086051 PMCID: PMC8186004 DOI: 10.1083/jcb.202103052] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 04/25/2023] Open
Abstract
In a neural circuit, synapses transfer information rapidly between neurons and transform this information during transfer. The diverse computational properties of synapses are shaped by the interactions between pre- and postsynaptic neurons. How synapses are assembled to form a neural circuit, and how the specificity of synaptic connections is achieved, is largely unknown. Here, I posit that synaptic adhesion molecules (SAMs) organize synapse formation. Diverse SAMs collaborate to achieve the astounding specificity and plasticity of synapses, with each SAM contributing different facets. In orchestrating synapse assembly, SAMs likely act as signal transduction devices. Although many candidate SAMs are known, only a few SAMs appear to have a major impact on synapse formation. Thus, a limited set of collaborating SAMs likely suffices to account for synapse formation. Strikingly, several SAMs are genetically linked to neuropsychiatric disorders, suggesting that impairments in synapse assembly are instrumental in the pathogenesis of neuropsychiatric disorders.
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The protective effect and potential mechanism of NRXN1 on learning and memory in ADHD rat models. Exp Neurol 2021; 344:113806. [PMID: 34228999 DOI: 10.1016/j.expneurol.2021.113806] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 06/09/2021] [Accepted: 07/02/2021] [Indexed: 11/23/2022]
Abstract
The learning and memory network is highly complex and remains unclear. The hippocampus is the location of learning and memory function. Impairment of synaptic morphology and synaptic plasticity (i.e., long-term potentiation) appears to cause learning and memory deficits. Several studies have indicated the role of NRXN1 in regulating the synaptic function, but little is known on its role in learning and memory dysfunction associated with attention deficit and hyperactivity disorder (ADHD). Our results showed that overexpression and interference of NRXN1 in vivo, respectively, affected learning and memory, as was assessed by Morris water maze tests, in spontaneously hypertensive rats (SHRs) and Sprague Dawley (SD) rats. We found that SD rats performed better after methylphenidate (MPH) treatment in salvage trials. Accordingly, the change of NRXN1 led to altered synapse-related gene (PSD95, SYN1, GAP43, NLGN1) expression, further providing evidence of its role in the maintenance of synaptic plasticity. We also verified that the expression of synapse-related genes synchronously changed with NRXN1expression in the behavioral assessment. The expression of NRXN1 was confirmed to affect the expression of synapse-related genes after its interference and overexpression in the primary hippocampal neurons in vitro. These results confirmed our hypothesis that NRXN1 might nucleate an overall trans-synaptic signaling network that controls synaptic plasticity and is responsible for impairments in learning and memory in ADHD. These findings suggest a possible protective role of NRXN1 in learning and memory in ADHD. Further RNA-seq sequencing revealed significant differences in the expression of 5-hydroxytryptamine receptor (5-HT6R), which was further verified at the cellular level, and the mechanism of NRXN1 affecting synaptic plasticity was preliminarily discussed.
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Abstract
OBJECTIVES Cannabis is a known teratogen. Data availability addressing both major congenital anomalies and cannabis use allowed us to explore their geospatial relationships. METHODS Data for the years 1998 to 2009 from Canada Health and Statistics Canada was analyzed in R. Maps have been drawn and odds ratios, principal component analysis, correlation matrices, least squares regression and geospatial regression analyses have been conducted using the R packages base, dplyr, epiR, psych, ggplot2, colorplaner and the spml and spreml functions from package splm. RESULTS Mapping showed cannabis use was more common in the northern Territories of Canada in the Second National Survey of Cannabis Use 2018. Total congenital anomalies, all cardiovascular defects, orofacial clefts, Downs syndrome and gastroschisis were all found to be more common in these same regions and rose as a function of cannabis exposure. When Canada was dichotomized into high and low cannabis use zones by Provinces v Territories the Territories had a higher rate of total congenital anomalies 450.026 v 390.413 (O.R. = 1.16 95%C.I. 1.08-1.25, P = 0.000058; attributable fraction in exposed 13.25%, 95%C.I. 7.04-19.04%). In geospatial analysis in a spreml spatial error model cannabis was significant both alone as a main effect (P < 2.0 × 10) and in all its first and second order interactions with both tobacco and opioids from P < 2.0 × 10. CONCLUSION These results show that the northern Territories of Canada share a higher rate of cannabis use together with elevated rates of total congenital anomalies, all cardiovascular defects, Down's syndrome and gastroschisis. This is the second report of a significant association between cannabis use and both total defects and all cardiovascular anomalies and the fourth published report of a link with Downs syndrome and thereby direct major genotoxicity. The correlative relationships described in this paper are confounded by many features of social disadvantage in Canada's northern territories. However, in the context of a similar broad spectrum of defects described both in animals and in epidemiological reports from Hawaii, Colorado, USA and Australia they are cause for particular concern and indicate further research.
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Klatt O, Repetto D, Brockhaus J, Reissner C, El Khallouqi A, Rohlmann A, Heine M, Missler M. Endogenous β-neurexins on axons and within synapses show regulated dynamic behavior. Cell Rep 2021; 35:109266. [PMID: 34133920 DOI: 10.1016/j.celrep.2021.109266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/21/2020] [Accepted: 05/26/2021] [Indexed: 11/25/2022] Open
Abstract
Neurexins are key organizer molecules that regulate synaptic function and are implicated in autism and schizophrenia. β-neurexins interact with numerous cell adhesion and receptor molecules, but their neuronal localization remains elusive. Using single-molecule tracking and high-resolution microscopy to detect neurexin1β and neurexin3β in primary hippocampal neurons from knockin mice, we demonstrate that endogenous β-neurexins are present in fewer than half of excitatory and inhibitory synapses. Moreover, we observe a large extrasynaptic pool of β-neurexins on axons and show that axonal β-neurexins diffuse with higher surface mobility than those transiently confined within synapses. Stimulation of neuronal activity further increases the mobility of synaptic and axonal β-neurexins, whereas inhibition causes the opposite. Blocking ectodomain cleavage by metalloproteases also reduces β-neurexin mobility and enhances glutamate release. These findings suggest that the surface mobility of endogenous β-neurexins inside and outside of synapses is dynamically regulated and linked to neuronal activity.
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Affiliation(s)
- Oliver Klatt
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany; Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Carsten Reissner
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Abderazzaq El Khallouqi
- Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany
| | - Astrid Rohlmann
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Martin Heine
- Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany.
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany.
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Cross-platform validation of neurotransmitter release impairments in schizophrenia patient-derived NRXN1-mutant neurons. Proc Natl Acad Sci U S A 2021; 118:2025598118. [PMID: 34035170 DOI: 10.1073/pnas.2025598118] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterozygous NRXN1 deletions constitute the most prevalent currently known single-gene mutation associated with schizophrenia, and additionally predispose to multiple other neurodevelopmental disorders. Engineered heterozygous NRXN1 deletions impaired neurotransmitter release in human neurons, suggesting a synaptic pathophysiological mechanism. Utilizing this observation for drug discovery, however, requires confidence in its robustness and validity. Here, we describe a multicenter effort to test the generality of this pivotal observation, using independent analyses at two laboratories of patient-derived and newly engineered human neurons with heterozygous NRXN1 deletions. Using neurons transdifferentiated from induced pluripotent stem cells that were derived from schizophrenia patients carrying heterozygous NRXN1 deletions, we observed the same synaptic impairment as in engineered NRXN1-deficient neurons. This impairment manifested as a large decrease in spontaneous synaptic events, in evoked synaptic responses, and in synaptic paired-pulse depression. Nrxn1-deficient mouse neurons generated from embryonic stem cells by the same method as human neurons did not exhibit impaired neurotransmitter release, suggesting a human-specific phenotype. Human NRXN1 deletions produced a reproducible increase in the levels of CASK, an intracellular NRXN1-binding protein, and were associated with characteristic gene-expression changes. Thus, heterozygous NRXN1 deletions robustly impair synaptic function in human neurons regardless of genetic background, enabling future drug discovery efforts.
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Neurexins regulate presynaptic GABA B-receptors at central synapses. Nat Commun 2021; 12:2380. [PMID: 33888718 PMCID: PMC8062527 DOI: 10.1038/s41467-021-22753-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 03/20/2021] [Indexed: 11/28/2022] Open
Abstract
Diverse signaling complexes are precisely assembled at the presynaptic active zone for dynamic modulation of synaptic transmission and synaptic plasticity. Presynaptic GABAB-receptors nucleate critical signaling complexes regulating neurotransmitter release at most synapses. However, the molecular mechanisms underlying assembly of GABAB-receptor signaling complexes remain unclear. Here we show that neurexins are required for the localization and function of presynaptic GABAB-receptor signaling complexes. At four model synapses, excitatory calyx of Held synapses in the brainstem, excitatory and inhibitory synapses on hippocampal CA1-region pyramidal neurons, and inhibitory basket cell synapses in the cerebellum, deletion of neurexins rendered neurotransmitter release significantly less sensitive to GABAB-receptor activation. Moreover, deletion of neurexins caused a loss of GABAB-receptors from the presynaptic active zone of the calyx synapse. These findings extend the role of neurexins at the presynaptic active zone to enabling GABAB-receptor signaling, supporting the notion that neurexins function as central organizers of active zone signaling complexes. Neurexins are evolutionarily conserved cell adhesion molecules that tune synapse formation and specification. Here the authors show that neurexins play similar roles in regulating presynaptic GABAB receptors at multiple CNS synapses.
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Fuccillo MV, Pak C. Copy number variants in neurexin genes: phenotypes and mechanisms. Curr Opin Genet Dev 2021; 68:64-70. [PMID: 33756113 PMCID: PMC8491281 DOI: 10.1016/j.gde.2021.02.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/17/2021] [Accepted: 02/23/2021] [Indexed: 11/11/2022]
Abstract
Neurexins are central to trans-synaptic cell adhesion and signaling during synapse specification and maintenance. The past two decades of human genetics research have identified structural variations in the neurexin gene family, in particular NRXN1 copy number variants (CNVs), implicated in multiple neuropsychiatric and developmental disorders. The heterogeneity and reduced penetrance of NRXN1 deletions, in addition to the pleiotropic, circuit-specific functions of NRXN1, present substantial obstacles to understanding how compromised NRXN1 function predisposes individuals to neuropsychiatric disorders. Here, we provide an updated review of NRXN1 genetics in disease, followed by recently published work using both human induced pluripotent stem cell (iPSC) derived systems and animal models to understand the mechanisms of disease pathophysiology. Finally, we suggest our outlook on how the field should progress to improve our understanding of neurexin mediated disease pathogenesis. We believe that understanding how structural genetic variants in NRXN1 contribute to disease pathophysiology requires parallel approaches in iPSC and mouse model systems, each leveraging their unique strengths — analysis of genetic interactions and background effects in iPSCs and neural circuit and behavioral analysis in mice.
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Affiliation(s)
- Marc V Fuccillo
- Dept. of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - ChangHui Pak
- Dept. of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, United States.
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50
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Khalaj AJ, Sterky FH, Sclip A, Schwenk J, Brunger AT, Fakler B, Südhof TC. Deorphanizing FAM19A proteins as pan-neurexin ligands with an unusual biosynthetic binding mechanism. J Cell Biol 2021; 219:151974. [PMID: 32706374 PMCID: PMC7480106 DOI: 10.1083/jcb.202004164] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022] Open
Abstract
Neurexins are presynaptic adhesion molecules that organize synapses by binding to diverse trans-synaptic ligands, but how neurexins are regulated is incompletely understood. Here we identify FAM19A/TAFA proteins, “orphan" cytokines, as neurexin regulators that interact with all neurexins, except for neurexin-1γ, via an unusual mechanism. Specifically, we show that FAM19A1-A4 bind to the cysteine-loop domain of neurexins by forming intermolecular disulfide bonds during transport through the secretory pathway. FAM19A-binding required both the cysteines of the cysteine-loop domain and an adjacent sequence of neurexins. Genetic deletion of neurexins suppressed FAM19A1 expression, demonstrating that FAM19As physiologically interact with neurexins. In hippocampal cultures, expression of exogenous FAM19A1 decreased neurexin O-glycosylation and suppressed its heparan sulfate modification, suggesting that FAM19As regulate the post-translational modification of neurexins. Given the selective expression of FAM19As in specific subtypes of neurons and their activity-dependent regulation, these results suggest that FAM19As serve as cell type–specific regulators of neurexin modifications.
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Affiliation(s)
- Anna J Khalaj
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Fredrik H Sterky
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Alessandra Sclip
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Jochen Schwenk
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Centres for Biological Signalling Studies (BIOSS) and Integrative Biological Signalling Studies (CIBSS), Freiburg, Germany.,Center for Basics in NeuroModulation, Freiburg, Germany
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
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