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Bin Ibrahim MZ, Wang Z, Sajikumar S. Synapses tagged, memories kept: synaptic tagging and capture hypothesis in brain health and disease. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230237. [PMID: 38853570 DOI: 10.1098/rstb.2023.0237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/13/2024] [Indexed: 06/11/2024] Open
Abstract
The synaptic tagging and capture (STC) hypothesis lays the framework on the synapse-specific mechanism of protein synthesis-dependent long-term plasticity upon synaptic induction. Activated synapses will display a transient tag that will capture plasticity-related products (PRPs). These two events, tag setting and PRP synthesis, can be teased apart and have been studied extensively-from their electrophysiological and pharmacological properties to the molecular events involved. Consequently, the hypothesis also permits interactions of synaptic populations that encode different memories within the same neuronal population-hence, it gives rise to the associativity of plasticity. In this review, the recent advances and progress since the experimental debut of the STC hypothesis will be shared. This includes the role of neuromodulation in PRP synthesis and tag integrity, behavioural correlates of the hypothesis and modelling in silico. STC, as a more sensitive assay for synaptic health, can also assess neuronal aberrations. We will also expound how synaptic plasticity and associativity are altered in ageing-related decline and pathological conditions such as juvenile stress, cancer, sleep deprivation and Alzheimer's disease. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Mohammad Zaki Bin Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore , Singapore 119077, Singapore
| | - Zijun Wang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore , Singapore 119077, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597, Singapore
- Neurobiology Programme, Life Sciences Institute, National University of Singapore , Singapore 119077, Singapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597, Singapore
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Nunes M, Madeira N, Fonseca R. Cdc42 activation is necessary for heterosynaptic cooperation and competition. Mol Cell Neurosci 2024; 129:103921. [PMID: 38428552 DOI: 10.1016/j.mcn.2024.103921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/03/2024] Open
Abstract
Synapses change their weights in response to neuronal activity and in turn, neuronal networks alter their response properties and ultimately allow the brain to store information as memories. As for memories, not all events are maintained over time. Maintenance of synaptic plasticity depends on the interplay between functional changes at synapses and the synthesis of plasticity-related proteins that are involved in stabilizing the initial functional changes. Different forms of synaptic plasticity coexist in time and across the neuronal dendritic area. Thus, homosynaptic plasticity refers to activity-dependent synaptic modifications that are input-specific, whereas heterosynaptic plasticity relates to changes in non-activated synapses. Heterosynaptic forms of plasticity, such as synaptic cooperation and competition allow neurons to integrate events that occur separated by relatively large time windows, up to one hour. Here, we show that activation of Cdc42, a Rho GTPase that regulates actin cytoskeleton dynamics, is necessary for the maintenance of long-term potentiation (LTP) in a time-dependent manner. Inhibiting Cdc42 activation does not alter the time-course of LTP induction and its initial expression but blocks its late maintenance. We show that Cdc42 activation is involved in the phosphorylation of cofilin, a protein involved in modulating actin filaments and that weak and strong synaptic activation leads to similar levels on cofilin phosphorylation, despite different levels of LTP expression. We show that Cdc42 activation is required for synapses to interact by cooperation or competition, supporting the hypothesis that modulation of the actin cytoskeleton provides an activity-dependent and time-restricted permissive state of synapses allowing synaptic plasticity to occur. We found that under competition, the sequence in which synapses are activated determines the degree of LTP destabilization, demonstrating that competition is an active destabilization process. Taken together, we show that modulation of actin cytoskeleton by Cdc42 activation is necessary for the expression of homosynaptic and heterosynaptic forms of plasticity. Determining the temporal and spatial rules that determine whether synapses cooperate or compete will allow us to understand how memories are associated.
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Affiliation(s)
- Mariana Nunes
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal
| | - Natália Madeira
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal
| | - Rosalina Fonseca
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal.
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3
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Prakash N, Matos HY, Sebaoui S, Tsai L, Tran T, Aromolaran A, Atrachji I, Campbell N, Goodrich M, Hernandez-Pineda D, Jesus Herrero M, Hirata T, Lischinsky J, Martinez W, Torii S, Yamashita S, Hosseini H, Sokolowski K, Esumi S, Kawasawa YI, Hashimoto-Torii K, Jones KS, Corbin JG. Connectivity and molecular profiles of Foxp2- and Dbx1-lineage neurons in the accessory olfactory bulb and medial amygdala. J Comp Neurol 2024; 532:e25545. [PMID: 37849047 PMCID: PMC10922300 DOI: 10.1002/cne.25545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 09/05/2023] [Accepted: 09/19/2023] [Indexed: 10/19/2023]
Abstract
In terrestrial vertebrates, the olfactory system is divided into main (MOS) and accessory (AOS) components that process both volatile and nonvolatile cues to generate appropriate behavioral responses. While much is known regarding the molecular diversity of neurons that comprise the MOS, less is known about the AOS. Here, focusing on the vomeronasal organ (VNO), the accessory olfactory bulb (AOB), and the medial amygdala (MeA), we reveal that populations of neurons in the AOS can be molecularly subdivided based on their ongoing or prior expression of the transcription factors Foxp2 or Dbx1, which delineate separate populations of GABAergic output neurons in the MeA. We show that a majority of AOB neurons that project directly to the MeA are of the Foxp2 lineage. Using single-neuron patch-clamp electrophysiology, we further reveal that in addition to sex-specific differences across lineage, the frequency of excitatory input to MeA Dbx1- and Foxp2-lineage neurons differs between sexes. Together, this work uncovers a novel molecular diversity of AOS neurons, and lineage and sex differences in patterns of connectivity.
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Affiliation(s)
- Nandkishore Prakash
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Heidi Y Matos
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Sonia Sebaoui
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Luke Tsai
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Tuyen Tran
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Adejimi Aromolaran
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Isabella Atrachji
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Nya Campbell
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Meredith Goodrich
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - David Hernandez-Pineda
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Maria Jesus Herrero
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Tsutomu Hirata
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Julieta Lischinsky
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Wendolin Martinez
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Shisui Torii
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Satoshi Yamashita
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Hassan Hosseini
- Department of Pharmacology, University of Michigan Medical
School, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan
Medical School, Ann Arbor, MI 48109, USA
| | - Katie Sokolowski
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Shigeyuki Esumi
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Yuka Imamura Kawasawa
- Department of Pharmacology, Pennsylvania State University
College of Medicine, Hershey, PA, USA
| | - Kazue Hashimoto-Torii
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
| | - Kevin S Jones
- Department of Pharmacology, University of Michigan Medical
School, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan
Medical School, Ann Arbor, MI 48109, USA
| | - Joshua G Corbin
- Center for Neuroscience Research, Children’s
Research Institute, Children’s National Hospital, Washington DC, USA
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Niepokny TD, Mintz EM. A Cannabinoid Receptor 1 Agonist Reduces Light-induced Phase Delays in Male But Not Female Mice. J Biol Rhythms 2023:7487304231166785. [PMID: 37190758 PMCID: PMC10330025 DOI: 10.1177/07487304231166785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Animals adapt to a changing environment by synchronizing their circadian rhythms to different stimuli, the strongest and most reliable being the daily light-dark cycle. Photic information reaches the central circadian pacemaker, the suprachiasmatic nucleus (SCN), which drives rhythms in physiology and behavior throughout the brain and body. The endocannabinoid system (ECS) is a neuromodulatory system that is present within the SCN, including the primary receptor, cannabinoid receptor 1 (CB1). Exogenous cannabinoids that target CB1 inhibit the phase-shifting effects of light in hamsters, mice, and rats. Furthermore, there is evidence in cultured microglial cells that cannabidiol (CBD), a constituent of Cannabis sativa, alters core circadian clock genes, while the CB1 agonist delta-9-tetrahydrocannabinol (THC) does not. The CB1 agonist studies were conducted using male animals only, but cannabinoids exhibit sex-dependent effects in various aspects of physiology and behavior. In addition, the effects of CBD on circadian behavioral rhythms have yet to be investigated. Therefore, we decided to test the effects of acute injections of CBD or the CB1 agonist CP 55,940 on light-induced phase delays in male and female C57BL/6J mice. Animals received a single injection at circadian time (CT) 15.5, followed by a 10-min light or dark (sham) pulse at CT 16. Running-wheel activity was monitored to determine activity levels and the behavioral phase shifts from different treatments. We observed a sex difference in the magnitude of phase delay size in response to CP 55,940 administration. Males had attenuated phase delays with increasing doses of CP 55,940, while females did not differ from control. Various doses of CBD had no effect on the phase-delaying effects of light in either sex. Our results show a sex difference in the gating of photic phase shifts by CB1 activation.
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Affiliation(s)
- Timothy D Niepokny
- Department of Biological Sciences, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio
| | - Eric M Mintz
- Department of Biological Sciences, School of Biomedical Sciences, and Brain Health Research Institute, Kent State University, Kent, Ohio
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Chong YS, Wong LW, Gaunt J, Lee YJ, Goh CS, Morris RGM, Ch'ng TH, Sajikumar S. Distinct contributions of ventral CA1/amygdala co-activation to the induction and maintenance of synaptic plasticity. Cereb Cortex 2023; 33:676-690. [PMID: 35253866 DOI: 10.1093/cercor/bhac093] [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: 12/24/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 02/03/2023] Open
Abstract
The amygdala is known to modulate hippocampal synaptic plasticity. One role could be an immediate effect of basolateral amygdala (BLA) in priming synaptic plasticity in the hippocampus. Another role could be through associative synaptic co-operation and competition that triggers events involved in the maintenance of synaptic potentiation. We present evidence that the timing and activity level of BLA stimulation are important factors for the induction and maintenance of long-term potentiation (LTP) in ventral hippocampal area CA1. A 100 Hz BLA co-stimulation facilitated the induction of LTP, whereas 200 Hz co-stimulation attenuated induction. A 100 Hz BLA co-stimulation also caused enhanced persistence, sufficient to prevent synaptic competition. This maintenance effect is likely through translational mechanisms, as mRNA expression of primary response genes was unaffected, whereas protein level of plasticity-related products was increased. Further understanding of the neural mechanisms of amygdala modulation on hippocampus could provide insights into the mechanisms of emotional disorders.
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Affiliation(s)
- Yee Song Chong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, SIngapore 117597, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore
| | - Lik-Wei Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, SIngapore 117597, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
| | - Jessica Gaunt
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Yan Jun Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.,Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637335, Singapore
| | - Cai Shan Goh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, SIngapore 117597, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore
| | - Richard G M Morris
- Laboratory for Cognitive Neuroscience, Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh EH8 9JZ, Scotland
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, SIngapore 117597, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore 117456, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
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Ma X, Vuyyuru H, Munsch T, Endres T, Lessmann V, Meis S. ProBDNF Dependence of LTD and Fear Extinction Learning in the Amygdala of Adult Mice. Cereb Cortex 2021; 32:1350-1364. [PMID: 34470044 DOI: 10.1093/cercor/bhab265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 11/12/2022] Open
Abstract
Neurotrophins are secreted proteins that control survival, differentiation, and synaptic plasticity. While mature neurotrophins regulate these functions via tyrosine kinase signaling (Trk), uncleaved pro-neurotrophins bind preferentially to the p75 neurotrophin receptor (p75NTR) and often exert opposite effects to those of mature neurotrophins. In the amygdala, brain-derived neurotrophic factor (BDNF) enables long-term potentiation as well as fear and fear extinction learning. In the present study, we focused on the impact of mature BDNF and proBDNF signaling on long-term depression (LTD) in the lateral amygdala (LA). Hence, we conducted extracellular field potential recordings in an in vitro slice preparation and recorded LTD in cortical and thalamic afferents to the LA. LTD was unchanged by acute block of BDNF/TrkB signaling. In contrast, LTD was inhibited by blocking p75NTR signaling, by disinhibition of the proteolytic cleavage of proBDNF into mature BDNF, and by preincubation with a function-blocking anti-proBDNF antibody. Since LTD-like processes in the amygdala are supposed to be related to fear extinction learning, we locally inhibited p75NTR signaling in the amygdala during or after fear extinction training, resulting in impaired fear extinction memory. Overall, these results suggest that in the amygdala proBDNF/p75NTR signaling plays a pivotal role in LTD and fear extinction learning.
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Affiliation(s)
- Xiaoyun Ma
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Harish Vuyyuru
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Thomas Munsch
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Thomas Endres
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Susanne Meis
- Institut für Physiologie, Otto-von-Guericke-Universität, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
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Fonseca R, Madeira N, Simoes C. Resilience to fear: The role of individual factors in amygdala response to stressors. Mol Cell Neurosci 2020; 110:103582. [PMID: 33346000 DOI: 10.1016/j.mcn.2020.103582] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 10/22/2022] Open
Abstract
Resilience to stress is an adaptive process that varies individually. Resilience refers to the adaptation, or the ability to maintain or regain mental health, despite being subject to adverse situation. Resilience is a dynamic concept that reflects a combination of internal individual factors, including age and gender interacting with external factors such as social, cultural and environmental factors. In the last decade, we have witnessed an increase in the prevalence of anxiety disorders, including post-traumatic stress disorder. Given that stress in unavoidable, it is of great interest to understand the neurophysiological mechanisms of resilience, the individual factors that may contribute to susceptibility and promote efficacious approaches to improve resilience. Here, we address this complex question, attempting at defining clear and operational definitions that may allow us to improve our analysis of behavior incorporating individuality. We examine how individual perception of the stressor can alter the outcome of an adverse situation using as an example, the fear-conditioning paradigm and discuss how individual differences in the reward system can contribute to resilience. Given the central role of the endocannabinoid system in regulating fear responses and anxiety, we discuss the evidence that polymorphisms in several molecules of this signaling system contribute to different anxiety phenotypes. The endocannabinoid system is highly interconnected with the serotoninergic and dopaminergic modulatory systems, contributing to individual differences in stress perception and coping mechanisms. We review how the individual variability in these modulatory systems can be used towards a multivariable assessment of stress risk. Incorporating individuality in our research will allow us to define biomarkers of anxiety disorders as well as assess prognosis, towards a personalized clinical approach to mental health.
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Affiliation(s)
- Rosalina Fonseca
- Cellular and Systems Neurobiology, Chronic Diseases Research Center (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130 1169-056 Lisboa, Portugal.
| | - Natália Madeira
- Cellular and Systems Neurobiology, Chronic Diseases Research Center (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130 1169-056 Lisboa, Portugal
| | - Carla Simoes
- Cellular and Systems Neurobiology, Chronic Diseases Research Center (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130 1169-056 Lisboa, Portugal
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