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Leduc T, El Alami H, Bougadir K, Bélanger-Nelson E, Mongrain V. Neuroligin-2 shapes individual slow waves during slow-wave sleep and the response to sleep deprivation in mice. Mol Autism 2024; 15:13. [PMID: 38570872 PMCID: PMC10993465 DOI: 10.1186/s13229-024-00594-5] [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: 11/28/2023] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Sleep disturbances are a common comorbidity to most neurodevelopmental disorders and tend to worsen disease symptomatology. It is thus crucial to understand mechanisms underlying sleep disturbances to improve patients' quality of life. Neuroligin-2 (NLGN2) is a synaptic adhesion protein regulating GABAergic transmission. It has been linked to autism spectrum disorders and schizophrenia in humans, and deregulations of its expression were shown to cause epileptic-like hypersynchronized cerebral activity in rodents. Importantly, the absence of Nlgn2 (knockout: KO) was previously shown to alter sleep-wake duration and quality in mice, notably increasing slow-wave sleep (SWS) delta activity (1-4 Hz) and altering its 24-h dynamics. This type of brain oscillation is involved in memory consolidation, and is also a marker of homeostatic sleep pressure. Sleep deprivation (SD) is notably known to impair cognition and the physiological response to sleep loss involves GABAergic transmission. METHODS Using electrocorticographic (ECoG) recordings, we here first aimed to verify how individual slow wave (SW; 0.5-4 Hz) density and properties (e.g., amplitude, slope, frequency) contribute to the higher SWS delta activity and altered 24-h dynamics observed in Nlgn2 KO mice. We further investigated the response of these animals to SD. Finally, we tested whether sleep loss affects the gene expression of Nlgn2 and related GABAergic transcripts in the cerebral cortex of wild-type mice using RNA sequencing. RESULTS Our results show that Nlgn2 KO mice have both greater SW amplitude and density, and that SW density is the main property contributing to the altered 24-h dynamics. We also found the absence of Nlgn2 to accelerate paradoxical sleep recovery following SD, together with profound alterations in ECoG activity across vigilance states. Sleep loss, however, did not modify the 24-h distribution of the hypersynchronized ECoG events observed in these mice. Finally, RNA sequencing confirmed an overall decrease in cortical expression of Nlgn2 and related GABAergic transcripts following SD in wild-type mice. CONCLUSIONS This work brings further insight into potential mechanisms of sleep duration and quality deregulation in neurodevelopmental disorders, notably involving NLGN2 and GABAergic neurotransmission.
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Affiliation(s)
- Tanya Leduc
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
- Centre d'études avancées en médecine du sommeil (CÉAMS), Recherche - Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- Centre de recherche du Centre hospitalier de l'Université de Montréal, 900, St-Denis street, Tour Viger Montréal, Montreal, QC, H2X 0A9, Canada
| | - Hiba El Alami
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
- Centre d'études avancées en médecine du sommeil (CÉAMS), Recherche - Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
| | - Khadija Bougadir
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
- Centre d'études avancées en médecine du sommeil (CÉAMS), Recherche - Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
| | - Erika Bélanger-Nelson
- Centre d'études avancées en médecine du sommeil (CÉAMS), Recherche - Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada
- Pfizer Canada ULC, Montreal, QC, Canada
| | - Valérie Mongrain
- Department of Neuroscience, Université de Montréal, Montreal, QC, Canada.
- Centre d'études avancées en médecine du sommeil (CÉAMS), Recherche - Centre intégré universitaire de santé et services sociaux du Nord-de-l'Île-de-Montréal, Montreal, QC, Canada.
- Centre de recherche du Centre hospitalier de l'Université de Montréal, 900, St-Denis street, Tour Viger Montréal, Montreal, QC, H2X 0A9, Canada.
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Howes OD, Onwordi EC. The synaptic hypothesis of schizophrenia version III: a master mechanism. Mol Psychiatry 2023; 28:1843-1856. [PMID: 37041418 PMCID: PMC10575788 DOI: 10.1038/s41380-023-02043-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 04/13/2023]
Abstract
The synaptic hypothesis of schizophrenia has been highly influential. However, new approaches mean there has been a step-change in the evidence available, and some tenets of earlier versions are not supported by recent findings. Here, we review normal synaptic development and evidence from structural and functional imaging and post-mortem studies that this is abnormal in people at risk and with schizophrenia. We then consider the mechanism that could underlie synaptic changes and update the hypothesis. Genome-wide association studies have identified a number of schizophrenia risk variants converging on pathways regulating synaptic elimination, formation and plasticity, including complement factors and microglial-mediated synaptic pruning. Induced pluripotent stem cell studies have demonstrated that patient-derived neurons show pre- and post-synaptic deficits, synaptic signalling alterations, and elevated, complement-dependent elimination of synaptic structures compared to control-derived lines. Preclinical data show that environmental risk factors linked to schizophrenia, such as stress and immune activation, can lead to synapse loss. Longitudinal MRI studies in patients, including in the prodrome, show divergent trajectories in grey matter volume and cortical thickness compared to controls, and PET imaging shows in vivo evidence for lower synaptic density in patients with schizophrenia. Based on this evidence, we propose version III of the synaptic hypothesis. This is a multi-hit model, whereby genetic and/or environmental risk factors render synapses vulnerable to excessive glia-mediated elimination triggered by stress during later neurodevelopment. We propose the loss of synapses disrupts pyramidal neuron function in the cortex to contribute to negative and cognitive symptoms and disinhibits projections to mesostriatal regions to contribute to dopamine overactivity and psychosis. It accounts for the typical onset of schizophrenia in adolescence/early adulthood, its major risk factors, and symptoms, and identifies potential synaptic, microglial and immune targets for treatment.
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Affiliation(s)
- Oliver D Howes
- Faculty of Medicine, Institute of Clinical Sciences (ICS), Imperial College London, London, W12 0NN, UK.
- Psychiatric Imaging Group, Medical Research Council, London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN, UK.
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 8AF, UK.
| | - Ellis Chika Onwordi
- Faculty of Medicine, Institute of Clinical Sciences (ICS), Imperial College London, London, W12 0NN, UK.
- Psychiatric Imaging Group, Medical Research Council, London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN, UK.
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 8AF, UK.
- Centre for Psychiatry and Mental Health, Wolfson Institute of Population Health, Queen Mary University of London, London, E1 2AB, UK.
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Kim A, Gu SM, Lee H, Kim DE, Hong JT, Yun J, Cha HJ. Prenatal ketamine exposure impairs prepulse inhibition via arginine vasopressin receptor 1A-mediated GABAergic neuronal dysfunction in the striatum. Biomed Pharmacother 2023; 160:114318. [PMID: 36738499 DOI: 10.1016/j.biopha.2023.114318] [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: 06/18/2021] [Revised: 01/17/2023] [Accepted: 01/26/2023] [Indexed: 02/05/2023] Open
Abstract
Ketamine is a widely used anesthetic with N-methyl-D-aspartate (NMDA) receptor antagonism. Exposure to ketamine and NMDA receptor antagonists may induce psychosis. However, the mechanism underlying the effects of ketamine on the immature brain remains unclear. In this study, NMDA receptor antagonists, ketamine and methoxetamine, were administered to pregnant F344 rats (E17). These regimens induce psychosis-like behaviors in the offspring, such as hyperlocomotion induced by MK-801, a non-competitive NMDA receptor antagonist. We also observed that prepulse inhibition (PPI) was significantly reduced. Interestingly, ketamine administration increased the arginine vasopressin receptor 1A (Avpr1a) expression levels in the striatum of offspring with abnormal behaviors. Methoxetamine, another NMDA receptor antagonist, also showed similar results. In addition, we demonstrated a viral vector-induced Avpr1a overexpression in the striatum-inhibited PPI. In the striatum of offspring, ketamine or methoxetamine treatment increased glutamate decarboxylase 67 (GAD67) and δ-aminobutyric acid (GABA) levels. These results show that prenatal NMDA receptor antagonist treatment induces GABAergic neuronal dysfunction and abnormalities in sensorimotor gating via regulating Avpr1a expression in the striatum.
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Affiliation(s)
- Aeseul Kim
- College of Pharmacy, Chungbuk National University, 194-31, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28160, the Republic of Korea
| | - Sun Mi Gu
- College of Pharmacy, Chungbuk National University, 194-31, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28160, the Republic of Korea
| | - Haemiru Lee
- Pharmacological Research Division, National Institute of Food and Drug Safety Evaluation (NIFDS), Ministry of Food and Drug Safety (MFDS), OHTAC 187, Osongsaengmyong 2-ro, Cheongju-si, Chungcheongbuk-do 28159, the Republic of Korea
| | - Dong Eun Kim
- Pharmacological Research Division, National Institute of Food and Drug Safety Evaluation (NIFDS), Ministry of Food and Drug Safety (MFDS), OHTAC 187, Osongsaengmyong 2-ro, Cheongju-si, Chungcheongbuk-do 28159, the Republic of Korea
| | - Jin Tae Hong
- College of Pharmacy, Chungbuk National University, 194-31, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28160, the Republic of Korea
| | - Jaesuk Yun
- College of Pharmacy, Chungbuk National University, 194-31, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28160, the Republic of Korea.
| | - Hye Jin Cha
- College of Veterinary Medicine, Gyeongsang National University, 501, Jinju-daero, Jinju-si, Gyeongsangnam-do 52828, the Republic of Korea.
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Liu X, Hua F, Yang D, Lin Y, Zhang L, Ying J, Sheng H, Wang X. Roles of neuroligins in central nervous system development: focus on glial neuroligins and neuron neuroligins. Lab Invest 2022; 20:418. [PMID: 36088343 PMCID: PMC9463862 DOI: 10.1186/s12967-022-03625-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/01/2022] [Indexed: 11/10/2022]
Abstract
Neuroligins are postsynaptic cell adhesion molecules that are relevant to many neurodevelopmental disorders. They are differentially enriched at the postsynapse and interact with their presynaptic ligands, neurexins, whose differential binding to neuroligins has been shown to regulate synaptogenesis, transmission, and other synaptic properties. The proper functioning of functional networks in the brain depends on the proper connection between neuronal synapses. Impaired synaptogenesis or synaptic transmission results in synaptic dysfunction, and these synaptic pathologies are the basis for many neurodevelopmental disorders. Deletions or mutations in the neuroligins genes have been found in patients with both autism and schizophrenia. It is because of the important role of neuroligins in synaptic connectivity and synaptic dysfunction that studies on neuroligins in the past have mainly focused on their expression in neurons. As studies on the expression of genes specific to various cells of the central nervous system deepened, neuroligins were found to be expressed in non-neuronal cells as well. In the central nervous system, glial cells are the most representative non-neuronal cells, which can also express neuroligins in large amounts, especially astrocytes and oligodendrocytes, and they are involved in the regulation of synaptic function, as are neuronal neuroligins. This review examines the mechanisms of neuron neuroligins and non-neuronal neuroligins in the central nervous system and also discusses the important role of neuroligins in the development of the central nervous system and neurodevelopmental disorders from the perspective of neuronal neuroligins and glial neuroligins.
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Blagburn-Blanco SV, Chappell MS, De Biase LM, DeNardo LA. Synapse-specific roles for microglia in development: New horizons in the prefrontal cortex. Front Mol Neurosci 2022; 15:965756. [PMID: 36003220 PMCID: PMC9394540 DOI: 10.3389/fnmol.2022.965756] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/13/2022] [Indexed: 11/19/2022] Open
Abstract
Dysfunction of both microglia and circuitry in the medial prefrontal cortex (mPFC) have been implicated in numerous neuropsychiatric disorders, but how microglia affect mPFC development in health and disease is not well understood. mPFC circuits undergo a prolonged maturation after birth that is driven by molecular programs and activity-dependent processes. Though this extended development is crucial to acquire mature cognitive abilities, it likely renders mPFC circuitry more susceptible to disruption by genetic and environmental insults that increase the risk of developing mental health disorders. Recent work suggests that microglia directly influence mPFC circuit maturation, though the biological factors underlying this observation remain unclear. In this review, we discuss these recent findings along with new studies on the cellular mechanisms by which microglia shape sensory circuits during postnatal development. We focus on the molecular pathways through which glial cells and immune signals regulate synaptogenesis and activity-dependent synaptic refinement. We further highlight how disruptions in these pathways are implicated in the pathogenesis of neurodevelopmental and psychiatric disorders associated with mPFC dysfunction, including schizophrenia and autism spectrum disorder (ASD). Using these disorders as a framework, we discuss microglial mechanisms that could link environmental risk factors including infections and stress with ongoing genetic programs to aberrantly shape mPFC circuitry.
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Affiliation(s)
- Sara V. Blagburn-Blanco
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
- Medical Scientist Training Program, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Megan S. Chappell
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Lindsay M. De Biase
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States
- *Correspondence: Lindsay M. De Biase,
| | - Laura A. DeNardo
- Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States
- Laura A. DeNardo,
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Investigating the Role of GABA in Neural Development and Disease Using Mice Lacking GAD67 or VGAT Genes. Int J Mol Sci 2022; 23:ijms23147965. [PMID: 35887307 PMCID: PMC9318753 DOI: 10.3390/ijms23147965] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/12/2022] [Accepted: 07/16/2022] [Indexed: 11/18/2022] Open
Abstract
Normal development and function of the central nervous system involves a balance between excitatory and inhibitory neurotransmission. Activity of both excitatory and inhibitory neurons is modulated by inhibitory signalling of the GABAergic and glycinergic systems. Mechanisms that regulate formation, maturation, refinement, and maintenance of inhibitory synapses are established in early life. Deviations from ideal excitatory and inhibitory balance, such as down-regulated inhibition, are linked with many neurological diseases, including epilepsy, schizophrenia, anxiety, and autism spectrum disorders. In the mammalian forebrain, GABA is the primary inhibitory neurotransmitter, binding to GABA receptors, opening chloride channels and hyperpolarizing the cell. We review the involvement of down-regulated inhibitory signalling in neurological disorders, possible mechanisms for disease progression, and targets for therapeutic intervention. We conclude that transgenic models of disrupted inhibitory signalling—in GAD67+/− and VGAT−/− mice—are useful for investigating the effects of down-regulated inhibitory signalling in a range of neurological diseases.
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Kim D, Jung H, Shirai Y, Kim H, Kim J, Lim D, Mori T, Lee H, Park D, Kim HY, Guo Q, Pang B, Qiu W, Cao X, Kouyama-Suzuki E, Uemura T, Kasem E, Fu Y, Kim S, Tokunaga A, Yoshizawa T, Suzuki T, Sakagami H, Lee KJ, Ko J, Tabuchi K, Um JW. IQSEC3 Deletion Impairs Fear Memory Through Upregulation of Ribosomal S6K1 Signaling in the Hippocampus. Biol Psychiatry 2022; 91:821-831. [PMID: 35219498 DOI: 10.1016/j.biopsych.2021.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/29/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND IQSEC3, a gephyrin-binding GABAergic (gamma-aminobutyric acidergic) synapse-specific guanine nucleotide exchange factor, was recently reported to regulate activity-dependent GABAergic synapse maturation, but the underlying signaling mechanisms remain incompletely understood. METHODS We generated mice with conditional knockout (cKO) of Iqsec3 to examine whether altered synaptic inhibition influences hippocampus-dependent fear memory formation. In addition, electrophysiological recordings, immunohistochemistry, and behavioral assays were used to address our question. RESULTS We found that Iqsec3-cKO induces a specific reduction in GABAergic synapse density, GABAergic synaptic transmission, and maintenance of long-term potentiation in the hippocampal CA1 region. In addition, Iqsec3-cKO mice exhibited impaired fear memory formation. Strikingly, Iqsec3-cKO caused abnormally enhanced activation of ribosomal P70-S6K1-mediated signaling in the hippocampus but not in the cortex. Furthermore, inhibiting upregulated S6K1 signaling by expressing dominant-negative S6K1 in the hippocampal CA1 of Iqsec3-cKO mice completely rescued impaired fear learning and inhibitory synapse density but not deficits in long-term potentiation maintenance. Finally, upregulated S6K1 signaling was rescued by IQSEC3 wild-type, but not by an ARF-GEF (adenosine diphosphate ribosylation factor-guanine nucleotide exchange factor) inactive IQSEC3 mutant. CONCLUSIONS Our results suggest that IQSEC3-mediated balanced synaptic inhibition in hippocampal CA1 is critical for the proper formation of hippocampus-dependent fear memory.
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Affiliation(s)
- Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Hyeji Jung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Dongseok Lim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Takuma Mori
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, Japan
| | - Hyojeong Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Hee Young Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Qi Guo
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Bo Pang
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Wen Qiu
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Xueshan Cao
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Emi Kouyama-Suzuki
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Takeshi Uemura
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Enas Kasem
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Department of Zoology, Faculty of Science, Kafrelsheikh University, Kafr el-Sheikh, Egypt
| | - Yu Fu
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Seungjoon Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Akinori Tokunaga
- Division of Laboratory Animal Resources, Life Science Research Laboratory, University of Fukui, Fukui, Japan
| | - Takahiro Yoshizawa
- Research Center for Supports to Advanced Science, Shinshu University, Nagano, Japan
| | - Tatsuo Suzuki
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Kanagawa, Japan
| | - Kea Joo Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea; Neural Circuits Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, Japan.
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea.
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Montanari M, Martella G, Bonsi P, Meringolo M. Autism Spectrum Disorder: Focus on Glutamatergic Neurotransmission. Int J Mol Sci 2022; 23:ijms23073861. [PMID: 35409220 PMCID: PMC8998955 DOI: 10.3390/ijms23073861] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/24/2022] [Accepted: 03/29/2022] [Indexed: 12/16/2022] Open
Abstract
Disturbances in the glutamatergic system have been increasingly documented in several neuropsychiatric disorders, including autism spectrum disorder (ASD). Glutamate-centered theories of ASD are based on evidence from patient samples and postmortem studies, as well as from studies documenting abnormalities in glutamatergic gene expression and metabolic pathways, including changes in the gut microbiota glutamate metabolism in patients with ASD. In addition, preclinical studies on animal models have demonstrated glutamatergic neurotransmission deficits and altered expression of glutamate synaptic proteins. At present, there are no approved glutamatergic drugs for ASD, but several ongoing clinical trials are currently focusing on evaluating in autistic patients glutamatergic pharmaceuticals already approved for other conditions. In this review, we provide an overview of the literature concerning the role of glutamatergic neurotransmission in the pathophysiology of ASD and as a potential target for novel treatments.
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Affiliation(s)
- Martina Montanari
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (M.M.); (G.M.)
- Department of Systems Neuroscience, University Tor Vergata, 00133 Rome, Italy
| | - Giuseppina Martella
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (M.M.); (G.M.)
| | - Paola Bonsi
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (M.M.); (G.M.)
- Correspondence: (P.B.); (M.M.)
| | - Maria Meringolo
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (M.M.); (G.M.)
- Correspondence: (P.B.); (M.M.)
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Terashima H, Minatohara K, Maruoka H, Okabe S. Imaging neural circuit pathology of autism spectrum disorders: autism-associated genes, animal models and the application of in vivo two-photon imaging. Microscopy (Oxf) 2022; 71:i81-i99. [DOI: 10.1093/jmicro/dfab039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/11/2021] [Accepted: 11/08/2021] [Indexed: 11/12/2022] Open
Abstract
Abstract
Recent advances in human genetics identified genetic variants involved in causing autism spectrum disorders (ASDs). Mouse models that mimic mutations found in patients with ASD exhibit behavioral phenotypes consistent with ASD symptoms. These mouse models suggest critical biological factors of ASD etiology. Another important implication of ASD genetics is the enrichment of ASD risk genes in molecules involved in developing synapses and regulating neural circuit function. Sophisticated in vivo imaging technologies applied to ASD mouse models identify common synaptic impairments in the neocortex, with genetic-mutation-specific defects in local neural circuits. In this article, we review synapse- and circuit-level phenotypes identified by in vivo two-photon imaging in multiple mouse models of ASD and discuss the contributions of altered synapse properties and neural circuit activity to ASD pathogenesis.
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Affiliation(s)
- Hiroshi Terashima
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keiichiro Minatohara
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hisato Maruoka
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Zhao H, Mao X, Zhu C, Zou X, Peng F, Yang W, Li B, Li G, Ge T, Cui R. GABAergic System Dysfunction in Autism Spectrum Disorders. Front Cell Dev Biol 2022; 9:781327. [PMID: 35198562 PMCID: PMC8858939 DOI: 10.3389/fcell.2021.781327] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autism spectrum disorder (ASD) refers to a series of neurodevelopmental diseases characterized by two hallmark symptoms, social communication deficits and repetitive behaviors. Gamma-aminobutyric acid (GABA) is one of the most important inhibitory neurotransmitters in the central nervous system (CNS). GABAergic inhibitory neurotransmission is critical for the regulation of brain rhythm and spontaneous neuronal activities during neurodevelopment. Genetic evidence has identified some variations of genes associated with the GABA system, indicating an abnormal excitatory/inhibitory (E/I) neurotransmission ratio implicated in the pathogenesis of ASD. However, the specific molecular mechanism by which GABA and GABAergic synaptic transmission affect ASD remains unclear. Transgenic technology enables translating genetic variations into rodent models to further investigate the structural and functional synaptic dysregulation related to ASD. In this review, we summarized evidence from human neuroimaging, postmortem, and genetic and pharmacological studies, and put emphasis on the GABAergic synaptic dysregulation and consequent E/I imbalance. We attempt to illuminate the pathophysiological role of structural and functional synaptic dysregulation in ASD and provide insights for future investigation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ranji Cui
- *Correspondence: Tongtong Ge, ; Ranji Cui,
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Camporesi E, Nilsson J, Vrillon A, Cognat E, Hourregue C, Zetterberg H, Blennow K, Becker B, Brinkmalm A, Paquet C, Brinkmalm G. Quantification of the trans-synaptic partners neurexin-neuroligin in CSF of neurodegenerative diseases by parallel reaction monitoring mass spectrometry. EBioMedicine 2022; 75:103793. [PMID: 34990894 PMCID: PMC8743209 DOI: 10.1016/j.ebiom.2021.103793] [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: 08/31/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Synaptic proteins are increasingly studied as biomarkers for synaptic dysfunction and loss, which are early and central events in Alzheimer's disease (AD) and strongly correlate with the degree of cognitive decline. In this study, we specifically investigated the synaptic binding partners neurexin (NRXN) and neuroligin (Nlgn) proteins, to assess their biomarker's potential. METHODS we developed a parallel reaction monitoring mass spectrometric method for the simultaneous quantification of NRXNs and Nlgns in cerebrospinal fluid (CSF) of neurodegenerative diseases, focusing on AD. Specifically, NRXN-1α, NRXN-1β, NRXN-2α, NRXN-3α and Nlgn1, Nlgn2, Nlgn3 and Nlgn4 proteins were targeted. FINDINGS The proteins were investigated in a clinical cohort including CSF from controls (n=22), mild cognitive impairment (MCI) due to AD (n=44), MCI due to other conditions (n=46), AD (n=77) and a group of non-AD dementia (n=28). No difference in levels of NRXNs and Nlgns was found between AD (both at dementia and MCI stages) or controls or the non-AD dementia group for any of the targeted proteins. NRXN and Nlgn proteins correlated strongly with each other, but only a weak correlation with the AD core biomarkers and the synaptic biomarkers neurogranin and growth-associated protein 43, was found, possibly reflecting different pathogenic processing at the synapse. INTERPRETATION we conclude that NRXN and Nlgn proteins do not represent suitable biomarkers for synaptic pathology in AD. The panel developed here could aid in future investigations of the potential involvement of NRXNs and Nlgns in synaptic dysfunction in other disorders of the central nervous system. FUNDING a full list of funding can be found under the acknowledgments section.
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Affiliation(s)
- Elena Camporesi
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.
| | - Johanna Nilsson
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Agathe Vrillon
- Université de Paris, Cognitive Neurology Center, GHU Nord APHP Hospital Lariboisière Fernand Widal, Paris, France; Université de Paris, Inserm UMR S11-44 Therapeutic Optimization in Neuropsychopharmacology, Paris, France
| | - Emmanuel Cognat
- Université de Paris, Cognitive Neurology Center, GHU Nord APHP Hospital Lariboisière Fernand Widal, Paris, France; Université de Paris, Inserm UMR S11-44 Therapeutic Optimization in Neuropsychopharmacology, Paris, France
| | - Claire Hourregue
- Université de Paris, Cognitive Neurology Center, GHU Nord APHP Hospital Lariboisière Fernand Widal, Paris, France
| | - Henrik Zetterberg
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; UK Dementia Research Institute at UCL, London, UK; Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK; Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Kaj Blennow
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Bruno Becker
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Ann Brinkmalm
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Claire Paquet
- Université de Paris, Cognitive Neurology Center, GHU Nord APHP Hospital Lariboisière Fernand Widal, Paris, France; Université de Paris, Inserm UMR S11-44 Therapeutic Optimization in Neuropsychopharmacology, Paris, France
| | - Gunnar Brinkmalm
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
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12
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Chowdhury D, Watters K, Biederer T. Synaptic recognition molecules in development and disease. Curr Top Dev Biol 2021; 142:319-370. [PMID: 33706921 DOI: 10.1016/bs.ctdb.2020.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Synaptic connectivity patterns underlie brain functions. How recognition molecules control where and when neurons form synapses with each other, therefore, is a fundamental question of cellular neuroscience. This chapter delineates adhesion and signaling complexes as well as secreted factors that contribute to synaptic partner recognition in the vertebrate brain. The sections follow a developmental perspective and discuss how recognition molecules (1) guide initial synaptic wiring, (2) provide for the rejection of incorrect partner choices, (3) contribute to synapse specification, and (4) support the removal of inappropriate synapses once formed. These processes involve a rich repertoire of molecular players and key protein families are described, notably the Cadherin and immunoglobulin superfamilies, Semaphorins/Plexins, Leucine-rich repeat containing proteins, and Neurexins and their binding partners. Molecular themes that diversify these recognition systems are defined and highlighted throughout the text, including the neuron-type specific expression and combinatorial action of recognition factors, alternative splicing, and post-translational modifications. Methodological innovations advancing the field such as proteomic approaches and single cell expression studies are additionally described. Further, the chapter highlights the importance of choosing an appropriate brain region to analyze synaptic recognition factors and the advantages offered by laminated structures like the hippocampus or retina. In a concluding section, the profound disease relevance of aberrant synaptic recognition for neurodevelopmental and psychiatric disorders is discussed. Based on the current progress, an outlook is presented on research goals that can further advance insights into how recognition molecules provide for the astounding precision and diversity of synaptic connections.
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Affiliation(s)
| | - Katherine Watters
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States; Neuroscience Graduate Program, Tufts University School of Medicine, Boston, MA, United States
| | - Thomas Biederer
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States.
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13
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Kim HY, Um JW, Ko J. Proper synaptic adhesion signaling in the control of neural circuit architecture and brain function. Prog Neurobiol 2021; 200:101983. [PMID: 33422662 DOI: 10.1016/j.pneurobio.2020.101983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Trans-synaptic cell-adhesion molecules are critical for governing various stages of synapse development and specifying neural circuit properties via the formation of multifarious signaling pathways. Recent studies have pinpointed the putative roles of trans-synaptic cell-adhesion molecules in mediating various cognitive functions. Here, we review the literature on the roles of a diverse group of central synaptic organizers, including neurexins (Nrxns), leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs), and their associated binding proteins, in regulating properties of specific type of synapses and neural circuits. In addition, we highlight the findings that aberrant synaptic adhesion signaling leads to alterations in the structures, transmission, and plasticity of specific synapses across diverse brain areas. These results seem to suggest that proper trans-synaptic signaling pathways by Nrxns, LAR-RPTPs, and their interacting network is likely to constitute central molecular complexes that form the basis for cognitive functions, and that these complexes are heterogeneously and complexly disrupted in many neuropsychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Hee Young Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea; Core Protein Resources Center, DGIST, Daegu, 42988, South Korea.
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea.
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14
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Ali H, Marth L, Krueger-Burg D. Neuroligin-2 as a central organizer of inhibitory synapses in health and disease. Sci Signal 2020; 13:13/663/eabd8379. [DOI: 10.1126/scisignal.abd8379] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Postsynaptic organizational protein complexes play central roles both in orchestrating synapse formation and in defining the functional properties of synaptic transmission that together shape the flow of information through neuronal networks. A key component of these organizational protein complexes is the family of synaptic adhesion proteins called neuroligins. Neuroligins form transsynaptic bridges with presynaptic neurexins to regulate various aspects of excitatory and inhibitory synaptic transmission. Neuroligin-2 (NLGN2) is the only member that acts exclusively at GABAergic inhibitory synapses. Altered expression and mutations in NLGN2 and several of its interacting partners are linked to cognitive and psychiatric disorders, including schizophrenia, autism, and anxiety. Research on NLGN2 has fundamentally shaped our understanding of the molecular architecture of inhibitory synapses. Here, we discuss the current knowledge on the molecular and cellular functions of mammalian NLGN2 and its role in the neuronal circuitry that regulates behavior in rodents and humans.
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Affiliation(s)
- Heba Ali
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Lena Marth
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Dilja Krueger-Burg
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, 37075 Göttingen, Germany
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15
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Martin-Kenny N, Bérubé NG. Effects of a postnatal Atrx conditional knockout in neurons on autism-like behaviours in male and female mice. J Neurodev Disord 2020; 12:17. [PMID: 32580781 PMCID: PMC7315487 DOI: 10.1186/s11689-020-09319-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 06/04/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Alpha-thalassemia/mental retardation, X-linked, or ATRX, is an autism susceptibility gene that encodes a chromatin remodeler. Mutations of ATRX result in the ATR-X intellectual disability syndrome and have been identified in autism spectrum disorder (ASD) patients. The mechanisms by which ATRX mutations lead to autism and autistic-like behaviours are not yet known. To address this question, we generated mice with postnatal Atrx inactivation in excitatory neurons of the forebrain and performed a battery of behavioural assays that assess autistic-like behaviours. METHODS Male and female mice with a postnatal conditional ablation of ATRX were generated using the Cre/lox system under the control of the αCaMKII gene promoter. These mice were tested in a battery of behavioural tests that assess autistic-like features. We utilized paradigms that measure social behaviour, repetitive, and stereotyped behaviours, as well as sensory gating. Statistics were calculated by two-way repeated measures ANOVA with Sidak's multiple comparison test or unpaired Student's t tests as indicated. RESULTS The behaviour tests revealed no significant differences between Atrx-cKO and control mice. We identified sexually dimorphic changes in odor habituation and discrimination; however, these changes did not correlate with social deficits. CONCLUSION The postnatal knockout of Atrx in forebrain excitatory neurons does not lead to autism-related behaviours in male or female mice.
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Affiliation(s)
- Nicole Martin-Kenny
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Division of Genetics and Development, Children's Health Research Institute, London, Ontario, Canada
| | - Nathalie G Bérubé
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
- Division of Genetics and Development, Children's Health Research Institute, London, Ontario, Canada.
- Department of Oncology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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16
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Aberrant mPFC GABAergic synaptic transmission and fear behavior in neuroligin-2 R215H knock-in mice. Brain Res 2020; 1730:146671. [DOI: 10.1016/j.brainres.2020.146671] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 11/19/2022]
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Troyano-Rodriguez E, Wirsig-Wiechmann CR, Ahmad M. Neuroligin-2 Determines Inhibitory Synaptic Transmission in the Lateral Septum to Optimize Stress-Induced Neuronal Activation and Avoidance Behavior. Biol Psychiatry 2019; 85:1046-1055. [PMID: 30878196 PMCID: PMC6555663 DOI: 10.1016/j.biopsych.2019.01.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Investigations in the neocortex have revealed that the balance of excitatory and inhibitory synaptic transmission (E/I ratio) is important for proper information processing. The disturbance of this balance underlies many neuropsychiatric illnesses, including autism spectrum disorder and schizophrenia. However, little is known about the contribution of E/I balance to the functioning of subcortical brain regions, such as the lateral septum (LS), a structure that plays important roles in regulating anxiety-related behavior. METHODS We manipulated E/I balance in the mouse LS by localized conditional deletion of neuroligin-2, a postsynaptic cell adhesion protein located at gamma-aminobutyric acidergic synapses and important for inhibitory synaptic transmission. We then performed analyses of synaptic transmission in the LS, stress-induced expression of immediate early gene c-fos, and anxiety-related and depression-related behavior. RESULTS The absence of neuroligin-2 in the LS in the mature mouse brain resulted in postsynaptic impairment of inhibitory synaptic transmission. Importantly, the reduced inhibition and resulting E/I imbalance decreased the responsiveness of LS neurons to stress. Furthermore, this E/I imbalance in the LS was associated with impaired stress-induced activation of downstream hypothalamic nuclei and reduced avoidance behavior of the animals in the elevated plus maze. CONCLUSIONS Our results described the synaptic function of neuroligin-2 in the LS, uncovered a positive association between c-Fos-expressing neurons in the LS and downstream hypothalamic areas and avoidance behavior, and demonstrated that intact inhibitory synaptic transmission and proper E/I balance are required for the optimal functioning of this subcortical circuit.
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Affiliation(s)
| | | | - Mohiuddin Ahmad
- Department of Cell Biology and Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
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Wide sensory filters underlie performance in memory-based discrimination and generalization. PLoS One 2019; 14:e0214817. [PMID: 30998708 PMCID: PMC6472767 DOI: 10.1371/journal.pone.0214817] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/20/2019] [Indexed: 11/30/2022] Open
Abstract
The way animals respond to a stimulus depends largely on an internal comparison between the current sensation and the memory of previous stimuli and outcomes. We know little about the accuracy with which the physical properties of the stimuli influence this type of memory-based discriminative decisions. Research has focused largely on discriminations between stimuli presented in quick succession, where animals can make relative inferences (same or different; higher or lower) from trial to trial. In the current study we used a memory-based task to explore how the stimulus’ physical properties, in this case tone frequency, affect auditory discrimination and generalization in mice. Mice performed ad libitum while living in groups in their home quarters. We found that the frequency distance between safe and conditioned sounds had a constraining effect on discrimination. As the safe-to-conditioned distance decreased across groups, performance deteriorated rapidly, even for frequency differences significantly larger than reported discrimination thresholds. Generalization width was influenced both by the physical distance and the previous experience of the mice, and was not accompanied by a decrease in sensory acuity. In conclusion, memory-based discriminations along a single stimulus dimension are inherently hard, reflecting a high overlap between the memory traces of the relevant stimuli. Memory-based discriminations rely therefore on wide sensory filters.
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Sakers K, Eroglu C. Control of neural development and function by glial neuroligins. Curr Opin Neurobiol 2019; 57:163-170. [PMID: 30991196 DOI: 10.1016/j.conb.2019.03.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 11/16/2022]
Abstract
Neuroligins are a family of cell adhesion molecules, which are best known for their functions as postsynaptic components of the trans-synaptic neurexin-neuroligin complexes. Neuroligins are highly conserved across evolution with important roles in the formation, maturation and function of synaptic structures. Mutations in the genes that encode for neuroligins have been linked to a number of neurodevelopmental disorders such as autism and schizophrenia, which stem from synaptic pathologies. Owing to their essential functions in regulating synaptic connectivity and their link to synaptic dysfunction in disease, previous studies on neuroligins have focused on neurons. Yet a recent work reveals that neuroligins are also expressed in the central nervous system by glial cells, such as astrocytes and oligodendrocytes, and perform important roles in controlling synaptic connectivity in a non-cell autonomous manner. In this review, we will highlight these recent findings demonstrating the important roles of glial neuroligins in regulating the development and connectivity of healthy and diseased brains.
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Affiliation(s)
- Kristina Sakers
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, United States; Regeneration Next Initiative, Duke University, Durham, NC 27710, United States.
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