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Aleksejenko N, Heller J. Super-resolution imaging to reveal the nanostructure of tripartite synapses. Neuronal Signal 2021; 5:NS20210003. [PMID: 34737894 PMCID: PMC8536832 DOI: 10.1042/ns20210003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Even though neurons are the main drivers of information processing in the brain and spinal cord, other cell types are important to mediate adequate flow of information. These include electrically passive glial cells such as microglia and astrocytes, which recently emerged as active partners facilitating proper signal transduction. In disease, these cells undergo pathophysiological changes that propel disease progression and change synaptic connections and signal transmission. In the healthy brain, astrocytic processes contact pre- and postsynaptic structures. These processes can be nanoscopic, and therefore only electron microscopy has been able to reveal their structure and morphology. However, electron microscopy is not suitable in revealing dynamic changes, and it is labour- and time-intensive. The dawn of super-resolution microscopy, techniques that 'break' the diffraction limit of conventional light microscopy, over the last decades has enabled researchers to reveal the nanoscopic synaptic environment. In this review, we highlight and discuss recent advances in our understanding of the nano-world of the so-called tripartite synapses, the relationship between pre- and postsynapse as well as astrocytic processes. Overall, novel super-resolution microscopy methods are needed to fully illuminate the intimate relationship between glia and neuronal cells that underlies signal transduction in the brain and that might be affected in diseases such as Alzheimer's disease and epilepsy.
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Affiliation(s)
- Natalija Aleksejenko
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
| | - Janosch P. Heller
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
- Queen Square Institute of Neurology, University College London, London, United Kingdom
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Abstract
Fluorescence imaging techniques play a pivotal role in our understanding of the nervous system. The emergence of various super-resolution microscopy methods and specialized fluorescent probes enables direct insight into neuronal structure and protein arrangements in cellular subcompartments with so far unmatched resolution. Super-resolving visualization techniques in neurons unveil a novel understanding of cytoskeletal composition, distribution, motility, and signaling of membrane proteins, subsynaptic structure and function, and neuron-glia interaction. Well-defined molecular targets in autoimmune and neurodegenerative disease models provide excellent starting points for in-depth investigation of disease pathophysiology using novel and innovative imaging methodology. Application of super-resolution microscopy in human brain samples and for testing clinical biomarkers is still in its infancy but opens new opportunities for translational research in neurology and neuroscience. In this review, we describe how super-resolving microscopy has improved our understanding of neuronal and brain function and dysfunction in the last two decades.
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Affiliation(s)
- Christian Werner
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology & Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Christian Geis
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
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53
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Zhang B, Lian W, Zhao J, Wang Z, Liu A, Du G. DL0410 Alleviates Memory Impairment in D-Galactose-Induced Aging Rats by Suppressing Neuroinflammation via the TLR4/MyD88/NF- κB Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6521146. [PMID: 34650664 PMCID: PMC8510815 DOI: 10.1155/2021/6521146] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/05/2021] [Accepted: 08/21/2021] [Indexed: 11/18/2022]
Abstract
Oxidative stress and neuroinflammation have been demonstrated to be linked with Alzheimer's disease (AD). In this study, we examined the protective effects of DL0410 in aging rats and explored the underlying mechanism against oxidative damage and neuroinflammation, which was then validated in LPS-stimulated BV2 microglia. We firstly investigated the improvement effects of DL0410 on learning and memory abilities and explored the potential mechanisms in D-gal-induced aging rats. An 8-week treatment with DL0410 significantly improved the learning and cognitive function of D-gal-stimulated Alzheimer's-like rats in the Morris water maze test, step-down test, and novel object recognition test, and the therapeutic effect of DL0410 at 10 mg/kg was even better than that of donepezil. What is more, the results showed that DL0410 alleviated neuron injury, increased the number of synapses, and improved the level of postsynaptic density protein 95 (PSD95) in the hippocampus and cortex. Next, we examined the protective effects of DL0410 against oxidative damage and neuroinflammation. Our observations indicated that DL0410 reduced the production of harmful oxidation products and promoted the antioxidative system, decreased the levels of proinflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6), and increased anti-inflammatory cytokines IL-10. Moreover, DL0410 inhibited the activation of astrocytes and microglia and suppressed the activation of the TLR4/MyD88/NF-κB signaling pathway. The anti-inflammation effect of DL0410 was further confirmed in LPS-stimulated BV2 cells, and the results showed that DL0410 reduced the level of inflammatory factors and inhibited the activation of the TLR4/MyD88/TRAF6/NF-κB signaling pathway in BV2 microglia. Molecular docking results indicated that DL0410 occupied the LPS recognition site in the TLR4/MD2 complex. Furthermore, the enhanced expression of claudin-1, claudin-5, occludin, CX43, and ZO-1 indicated that DL0410 protected the blood-brain barrier (BBB) integrity. Together, these results suggest that DL0410 exerts neuroprotective effects against hippocampus and cortex injury induced by D-galactose, and the possible mechanisms include antioxidative stress, antineuroinflammation, improving synaptic plasticity, and maintaining BBB integrity, which is mediated by the TLR4/MyD88/NF-κB signaling pathway inhibition. We suggest that DL0410 is a promising candidate for AD treatment.
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Affiliation(s)
- Baoyue Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Wenwen Lian
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Jun Zhao
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Zhe Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Ailin Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Guanhua Du
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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Curran OE, Qiu Z, Smith C, Grant SGN. A single-synapse resolution survey of PSD95-positive synapses in twenty human brain regions. Eur J Neurosci 2021; 54:6864-6881. [PMID: 32492218 PMCID: PMC7615673 DOI: 10.1111/ejn.14846] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
Mapping the molecular composition of individual excitatory synapses across the mouse brain reveals high synapse diversity with each brain region showing a distinct composition of synapse types. As a first step towards systematic mapping of synapse diversity across the human brain, we have labelled and imaged synapses expressing the excitatory synapse protein PSD95 in twenty human brain regions, including 13 neocortical, two subcortical, one hippocampal, one cerebellar and three brainstem regions, in four phenotypically normal individuals. We quantified the number, size and intensity of individual synaptic puncta and compared their regional distributions. We found that each region showed a distinct signature of synaptic puncta parameters. Comparison of brain regions showed that cortical and hippocampal structures are similar, and distinct from those of cerebellum and brainstem. Comparison of synapse parameters from human and mouse brain revealed conservation of parameters, hierarchical organization of brain regions and network architecture. This work illustrates the feasibility of generating a systematic single-synapse resolution atlas of the human brain, a potentially significant resource in studies of brain health and disease.
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Affiliation(s)
- Olimpia E Curran
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Zhen Qiu
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Colin Smith
- Academic Neuropathology, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, Edinburgh, UK
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55
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Shen M, Lian N, Song C, Qin C, Yu Y, Yu Y. Different Anesthetic Drugs Mediate Changes in Neuroplasticity During Cognitive Impairment in Sleep-Deprived Rats via Different Factors. Med Sci Monit 2021; 27:e932422. [PMID: 34564688 PMCID: PMC8482804 DOI: 10.12659/msm.932422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Perioperative neuro-cognitive disorders (PND) are preoperative and postoperative complications of multiple nervous systems, typically manifested as decreased memory and learning ability after surgery. It was used to replace the original definition of postoperative cognitive dysfunctions (POCD) from 2018. Our previous studies have shown that sevoflurane inhalation can lead to cognitive dysfunction in Sprague-Dawley rats, but the specific mechanism is still unclear. Material/Methods Thirty-six male Sprague-Dawley rats were randomly divided into 6 groups (n=6): the SD group was given 24-h acute sleep deprivation; Sevoflurane was inhaled for 2 h in the Sevo group. Two mL propofol was injected into the tail vein of rats in the Prop group. The rats in the SD+Sevo group and SD+Prop group were deprived of sleep before intervention in the same way as before. Results We noted significant behavioral changes in rats treated with SIK3 inhibitors or tau phosphorylation agonists before propofol injection or sevoflurane inhalation, with associated protein levels and dendritic spine density documented. Sevoflurane anesthesia-induced cognitive impairment following acute sleep deprivation was more pronounced than sleep deprivation-induced cognitive impairment alone and resulted in increased brain SIK3 levels, increased phosphorylation of total tau and tau, and decreased acetylation modifications. After using propofol, the cognitive function returned to baseline levels with a series of reversals of cognitive dysfunction. Conclusions These results suggest that sevoflurane inhalation via the SIK3 pathway aggravates cognitive impairment after acute sleep deprivation and that propofol anesthesia reverses the effects of sleep deprivation by affecting modifications of tau protein.
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Affiliation(s)
- Mengxi Shen
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
| | - Naqi Lian
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
| | - Chengcheng Song
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
| | - Chao Qin
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
| | - Yang Yu
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
| | - Yonghao Yu
- Department of Anesthesia, Tianjin Medical University General Hospital, Tianjin, China (mainland).,Tianjin Institute of Anesthesiology, Tianjin, China (mainland)
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56
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Manabe T, Rácz I, Schwartz S, Oberle L, Santarelli F, Emmrich JV, Neher JJ, Heneka MT. Systemic inflammation induced the delayed reduction of excitatory synapses in the CA3 during ageing. J Neurochem 2021; 159:525-542. [PMID: 34379806 DOI: 10.1111/jnc.15491] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/27/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022]
Abstract
Sepsis-associated encephalopathy (SAE) represents diverse cerebral dysfunctions in response to pathogen-induced systemic inflammation. Peripheral exposure to lipopolysaccharide (LPS), a component of the gram-negative bacterial cell wall, has been extensively used to model systemic inflammation. Our previous studies suggested that LPS led to hippocampal neuron death and synaptic destruction in vivo. However, the underlying roles of activated microglia in these neuronal changes remained unclear. Here, LPS from two different bacterial strains (Salmonella enterica or E. coli) were compared and injected in 14- to 16-month-old mice and evaluated for neuroinflammation and neuronal integrity in the hippocampus at 7 or 63 days post-injection (dpi). LPS injection resulted in persistent neuroinflammation lasting for seven days and a subsequent normalisation by 63 dpi. Of note, increases in proinflammatory cytokines, microglial morphology and microglial mean lysosome volume were more pronounced after E. coli LPS injection than Salmonella LPS at 7 dpi. While inhibitory synaptic puncta density remained normal, excitatory synaptic puncta were locally reduced in the CA3 region of the hippocampus at 63 dpi. Finally, we provide evidence that excitatory synapses coated with complement factor 3 (C3) decreased between 7 dpi and 63 dpi. Although we did not find an increase of synaptic pruning by microglia, it is plausible that microglia recognised and eliminated these C3-tagged synapses between the two time-points of investigation. Since a region-specific decline of CA3 synapses has previously been reported during normal ageing, we postulate that systemic inflammation may have accelerated or worsened the CA3 synaptic changes in the ageing brain.
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Affiliation(s)
- Tatsuya Manabe
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Ildikó Rácz
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Stephanie Schwartz
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Linda Oberle
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076, Tübingen, Germany
| | | | - Julius V Emmrich
- Department of Neurology and Department of Experimental Neurology, Freie Universität Berlin, Humboldt Universität zu Berlin, Berlin Institute of Health, Berlin, 10117, Germany
| | - Jonas J Neher
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), 72076, Tübingen, Germany
| | - Michael T Heneka
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University of Bonn Medical Center, Venusberg-Campus 1, 53127, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany.,Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
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Petit-Pedrol M, Groc L. Regulation of membrane NMDA receptors by dynamics and protein interactions. J Cell Biol 2021; 220:211609. [PMID: 33337489 PMCID: PMC7754687 DOI: 10.1083/jcb.202006101] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
Understanding neurotransmitter system crosstalk in the brain is a major challenge in neurobiology. Several intracellular and genomic cascades have been identified in this crosstalk. However, the discovery that neurotransmitter receptors are highly diffusive in the plasma membrane of neurons, where they form heterocomplexes with other proteins, has profoundly changed our view of neurotransmitter signaling. Here, we review new insights into neurotransmitter crosstalk at the plasma membrane. We focus on the membrane organization and interactome of the ionotropic glutamate N-methyl-D-aspartate receptor (NMDAR) that plays a central role in excitatory synaptic and network physiology and is involved in the etiology of several major neuropsychiatric disorders. The nanoscale organization and dynamics of NMDAR is a key regulatory process for glutamate synapse transmission, plasticity, and crosstalk with other neurotransmitter systems, such as the monoaminergic ones. The plasma membrane appears to be a prime regulatory compartment for spatial and temporal crosstalk between neurotransmitter systems in the healthy and diseased brain. Understanding the molecular mechanisms regulating membrane neurotransmitter receptor crosstalk will likely open research avenues for innovative therapeutical strategies.
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Affiliation(s)
- Mar Petit-Pedrol
- Université de Bordeaux, Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, Unité Mixte de Recherche 5297, Bordeaux, France
| | - Laurent Groc
- Université de Bordeaux, Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, Unité Mixte de Recherche 5297, Bordeaux, France
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LGI1-ADAM22-MAGUK configures transsynaptic nanoalignment for synaptic transmission and epilepsy prevention. Proc Natl Acad Sci U S A 2021; 118:2022580118. [PMID: 33397806 PMCID: PMC7826393 DOI: 10.1073/pnas.2022580118] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
This study addresses a fundamental question in neuroscience, namely how does the presynaptic component of the synapse precisely align with the postsynaptic component? This is essential for the proper transmission of signals across the synapse. This paper focuses on a set of transsynaptic, epilepsy-related proteins that are essential for this alignment. We show that the LGI1–ADAM22–MAGUK complex is a key player in the nanoarchitecture of the synapse, such that the release site is directly apposed to the nanocluster of glutamate receptors. Physiological functioning and homeostasis of the brain rely on finely tuned synaptic transmission, which involves nanoscale alignment between presynaptic neurotransmitter-release machinery and postsynaptic receptors. However, the molecular identity and physiological significance of transsynaptic nanoalignment remain incompletely understood. Here, we report that epilepsy gene products, a secreted protein LGI1 and its receptor ADAM22, govern transsynaptic nanoalignment to prevent epilepsy. We found that LGI1–ADAM22 instructs PSD-95 family membrane-associated guanylate kinases (MAGUKs) to organize transsynaptic protein networks, including NMDA/AMPA receptors, Kv1 channels, and LRRTM4–Neurexin adhesion molecules. Adam22ΔC5/ΔC5 knock-in mice devoid of the ADAM22–MAGUK interaction display lethal epilepsy of hippocampal origin, representing the mouse model for ADAM22-related epileptic encephalopathy. This model shows less-condensed PSD-95 nanodomains, disordered transsynaptic nanoalignment, and decreased excitatory synaptic transmission in the hippocampus. Strikingly, without ADAM22 binding, PSD-95 cannot potentiate AMPA receptor-mediated synaptic transmission. Furthermore, forced coexpression of ADAM22 and PSD-95 reconstitutes nano-condensates in nonneuronal cells. Collectively, this study reveals LGI1–ADAM22–MAGUK as an essential component of transsynaptic nanoarchitecture for precise synaptic transmission and epilepsy prevention.
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Obashi K, Taraska JW, Okabe S. The role of molecular diffusion within dendritic spines in synaptic function. J Gen Physiol 2021; 153:e202012814. [PMID: 33720306 PMCID: PMC7967910 DOI: 10.1085/jgp.202012814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/16/2021] [Indexed: 12/21/2022] Open
Abstract
Spines are tiny nanoscale protrusions from dendrites of neurons. In the cortex and hippocampus, most of the excitatory postsynaptic sites reside in spines. The bulbous spine head is connected to the dendritic shaft by a thin membranous neck. Because the neck is narrow, spine heads are thought to function as biochemically independent signaling compartments. Thus, dynamic changes in the composition, distribution, mobility, conformations, and signaling properties of molecules contained within spines can account for much of the molecular basis of postsynaptic function and regulation. A major factor in controlling these changes is the diffusional properties of proteins within this small compartment. Advances in measurement techniques using fluorescence microscopy now make it possible to measure molecular diffusion within single dendritic spines directly. Here, we review the regulatory mechanisms of diffusion in spines by local intra-spine architecture and discuss their implications for neuronal signaling and synaptic plasticity.
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Affiliation(s)
- Kazuki Obashi
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Justin W. Taraska
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Hagan MF, Grason GM. Equilibrium mechanisms of self-limiting assembly. REVIEWS OF MODERN PHYSICS 2021; 93:025008. [PMID: 35221384 PMCID: PMC8880259 DOI: 10.1103/revmodphys.93.025008] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Self-assembly is a ubiquitous process in synthetic and biological systems, broadly defined as the spontaneous organization of multiple subunits (e.g. macromolecules, particles) into ordered multi-unit structures. The vast majority of equilibrium assembly processes give rise to two states: one consisting of dispersed disassociated subunits, and the other, a bulk-condensed state of unlimited size. This review focuses on the more specialized class of self-limiting assembly, which describes equilibrium assembly processes resulting in finite-size structures. These systems pose a generic and basic question, how do thermodynamic processes involving non-covalent interactions between identical subunits "measure" and select the size of assembled structures? In this review, we begin with an introduction to the basic statistical mechanical framework for assembly thermodynamics, and use this to highlight the key physical ingredients that ensure equilibrium assembly will terminate at finite dimensions. Then, we introduce examples of self-limiting assembly systems, and classify them within this framework based on two broad categories: self-closing assemblies and open-boundary assemblies. These include well-known cases in biology and synthetic soft matter - micellization of amphiphiles and shell/tubule formation of tapered subunits - as well as less widely known classes of assemblies, such as short-range attractive/long-range repulsive systems and geometrically-frustrated assemblies. For each of these self-limiting mechanisms, we describe the physical mechanisms that select equilibrium assembly size, as well as potential limitations of finite-size selection. Finally, we discuss alternative mechanisms for finite-size assemblies, and draw contrasts with the size-control that these can achieve relative to self-limitation in equilibrium, single-species assemblies.
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Affiliation(s)
- Michael F Hagan
- Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454, USA
| | - Gregory M Grason
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
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Yang X, Annaert W. The Nanoscopic Organization of Synapse Structures: A Common Basis for Cell Communication. MEMBRANES 2021; 11:248. [PMID: 33808285 PMCID: PMC8065904 DOI: 10.3390/membranes11040248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 11/16/2022]
Abstract
Synapse structures, including neuronal and immunological synapses, can be seen as the plasma membrane contact sites between two individual cells where information is transmitted from one cell to the other. The distance between the two plasma membranes is only a few tens of nanometers, but these areas are densely populated with functionally different proteins, including adhesion proteins, receptors, and transporters. The narrow space between the two plasma membranes has been a barrier for resolving the synaptic architecture due to the diffraction limit in conventional microscopy (~250 nm). Various advanced super-resolution microscopy techniques, such as stimulated emission depletion (STED), structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM), bypass the diffraction limit and provide a sub-diffraction-limit resolving power, ranging from 10 to 100 nm. The studies using super-resolution microscopy have revealed unprecedented details of the nanoscopic organization and dynamics of synaptic molecules. In general, most synaptic proteins appear to be heterogeneously distributed and form nanodomains at the membranes. These nanodomains are dynamic functional units, playing important roles in mediating signal transmission through synapses. Herein, we discuss our current knowledge on the super-resolution nanoscopic architecture of synapses and their functional implications, with a particular focus on the neuronal synapses and immune synapses.
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Affiliation(s)
| | - Wim Annaert
- VIB Center for Brain and Disease Research and KU Leuven, Department of Neurosciences, Gasthuisberg, B-3000 Leuven, Belgium;
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Liu H, Zhang Z, Zang C, Wang L, Yang H, Sheng C, Shang J, Zhao Z, Yuan F, Yu Y, Yao X, Bao X, Zhang D. GJ-4 ameliorates memory impairment in focal cerebral ischemia/reperfusion of rats via inhibiting JAK2/STAT1-mediated neuroinflammation. JOURNAL OF ETHNOPHARMACOLOGY 2021; 267:113491. [PMID: 33091490 DOI: 10.1016/j.jep.2020.113491] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 09/30/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Gardenia jasminoides J. Ellis (Fructus Gardenia) is a traditional Chinese medicine with diverse pharmacological functions, such as anti-inflammation, anti-depression, as well as improvement of cognition and ischemia brain injury. GJ-4 is a natural extract from Gardenia jasminoides J. Ellis (Fructus Gardenia) and has been proved to improve memory impairment in Alzheimer's disease (AD) mouse model in our previous studies. AIM OF THE STUDY This study aimed to evaluate the therapeutic effects of GJ-4 on vascular dementia (VD) and explore the potential mechanisms. MATERIAL AND METHODS In our experiment, a focal cerebral ischemia and reperfusion rat model was successfully developed by the middle cerebral artery occlusion and reperfusion (MCAO/R). GJ-4 (10 mg/kg, 25 mg/kg, 50 mg/kg) and nimodipine (10 mg/kg) were orally administered to rats once a day for consecutive 12 days. Learning and memory behavioral performance was assayed by step-down test and Morris water maze test. The neurological scoring test was performed to evaluate the neurological function of rats. 2,3,5-Triphenyltetrazolium chloride (TTC) staining and Nissl staining were respectively employed to determine the infarct condition and neuronal injury of the brain. Iba1 immunohistochemistry was used to show the activation of microglia. Moreover, the synaptic damage and inflammatory level were detected by Western blot. RESULTS GJ-4 could significantly improve memory impairment, cerebral infraction, as well as neurological deficits of VD rats induced by MCAO/R. Further research indicated VD-induced neuronal injury was alleviated by GJ-4. In addition, GJ-4 could protect synapse of VD rats by upregulating synaptophysin (SYP) expression, post synaptic density 95 protein (PSD95) expression, and downregulating N-Methyl-D-Aspartate receptor 1 (NMDAR1) expression. Subsequent investigation of the underlying mechanisms identified that GJ-4 could suppress neuroinflammatory responses, supported by inhibited activation of microglia and reduced expression of inflammatory proteins, which ultimately exerted neuroprotective effects on VD. Further mechanistic study indicated that janus kinase 2 (JAK2)/signal transducer and activator of transcription 1 (STAT1) pathway was inhibited by GJ-4 treatment. CONCLUSION These results suggested that GJ-4 might serve as a potential drug to improve VD. In addition, our study indicated that inhibition of neuroinflammation might be a promising target to treat VD.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Brain/enzymology
- Brain/pathology
- Brain/physiopathology
- Dementia, Vascular/enzymology
- Dementia, Vascular/etiology
- Dementia, Vascular/prevention & control
- Dementia, Vascular/psychology
- Disease Models, Animal
- Drugs, Chinese Herbal/pharmacology
- Gardenia
- Infarction, Middle Cerebral Artery/complications
- Infarction, Middle Cerebral Artery/drug therapy
- Infarction, Middle Cerebral Artery/enzymology
- Infarction, Middle Cerebral Artery/physiopathology
- Inflammation Mediators/metabolism
- Janus Kinase 2/metabolism
- Male
- Memory/drug effects
- Memory Disorders/enzymology
- Memory Disorders/etiology
- Memory Disorders/prevention & control
- Memory Disorders/psychology
- Microglia/drug effects
- Microglia/metabolism
- Microglia/pathology
- Neuroprotective Agents/pharmacology
- Nootropic Agents/pharmacology
- Plant Extracts/pharmacology
- Rats, Sprague-Dawley
- Reperfusion Injury/enzymology
- Reperfusion Injury/etiology
- Reperfusion Injury/physiopathology
- Reperfusion Injury/prevention & control
- STAT1 Transcription Factor/metabolism
- Signal Transduction
- Synapses/drug effects
- Synapses/metabolism
- Synapses/pathology
- Rats
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Affiliation(s)
- Hui Liu
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Zihong Zhang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Caixia Zang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Lu Wang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Hanyu Yang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Chanjuan Sheng
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Junmei Shang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Zhe Zhao
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Fangyu Yuan
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China
| | - Yang Yu
- Institute of TCM, Natural Products College of Pharmacy, Jinan University, Guangzhou, 510632, China
| | - Xinsheng Yao
- Institute of TCM, Natural Products College of Pharmacy, Jinan University, Guangzhou, 510632, China
| | - Xiuqi Bao
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China.
| | - Dan Zhang
- State Key Laboratory of Bioactive Substrate and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, 1 Xian Nong Tan Street, Beijing, 100050, China.
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63
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Jamjoom AAB, Rhodes J, Andrews PJD, Grant SGN. The synapse in traumatic brain injury. Brain 2021; 144:18-31. [PMID: 33186462 PMCID: PMC7880663 DOI: 10.1093/brain/awaa321] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is a risk factor for dementia later in life. Research into the pathophysiology of TBI has focused on the impact of injury on the neuron. However, recent advances have shown that TBI has a major impact on synapse structure and function through a combination of the immediate mechanical insult and the ensuing secondary injury processes, leading to synapse loss. In this review, we highlight the role of the synapse in TBI pathophysiology with a focus on the confluence of multiple secondary injury processes including excitotoxicity, inflammation and oxidative stress. The primary insult triggers a cascade of events in each of these secondary processes and we discuss the complex interplay that occurs at the synapse. We also examine how the synapse is impacted by traumatic axonal injury and the role it may play in the spread of tau after TBI. We propose that astrocytes play a crucial role by mediating both synapse loss and recovery. Finally, we highlight recent developments in the field including synapse molecular imaging, fluid biomarkers and therapeutics. In particular, we discuss advances in our understanding of synapse diversity and suggest that the new technology of synaptome mapping may prove useful in identifying synapses that are vulnerable or resistant to TBI.
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Affiliation(s)
- Aimun A B Jamjoom
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Jonathan Rhodes
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Peter J D Andrews
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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64
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Imaging of spine synapses using super-resolution microscopy. Anat Sci Int 2021; 96:343-358. [PMID: 33459976 DOI: 10.1007/s12565-021-00603-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 01/04/2021] [Indexed: 12/17/2022]
Abstract
Neuronal circuits in the neocortex and hippocampus are essential for higher brain functions such as motor learning and spatial memory. In the mammalian forebrain, most excitatory synapses of pyramidal neurons are formed on spines, which are tiny protrusions extending from the dendritic shaft. The spine contains specialized molecular machinery that regulates synaptic transmission and plasticity. Spine size correlates with the efficacy of synaptic transmission, and spine morphology affects signal transduction at the post-synaptic compartment. Plasticity-related changes in the structural and molecular organization of spine synapses are thought to underlie the cellular basis of learning and memory. Recent advances in super-resolution microscopy have revealed the molecular mechanisms of the nanoscale synaptic structures regulating synaptic transmission and plasticity in living neurons, which are difficult to investigate using electron microscopy alone. In this review, we summarize recent advances in super-resolution imaging of spine synapses and discuss the implications of nanoscale structures in the regulation of synaptic function, learning, and memory.
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65
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Minehart JA, Speer CM. A Picture Worth a Thousand Molecules-Integrative Technologies for Mapping Subcellular Molecular Organization and Plasticity in Developing Circuits. Front Synaptic Neurosci 2021; 12:615059. [PMID: 33469427 PMCID: PMC7813761 DOI: 10.3389/fnsyn.2020.615059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
A key challenge in developmental neuroscience is identifying the local regulatory mechanisms that control neurite and synaptic refinement over large brain volumes. Innovative molecular techniques and high-resolution imaging tools are beginning to reshape our view of how local protein translation in subcellular compartments drives axonal, dendritic, and synaptic development and plasticity. Here we review recent progress in three areas of neurite and synaptic study in situ-compartment-specific transcriptomics/translatomics, targeted proteomics, and super-resolution imaging analysis of synaptic organization and development. We discuss synergies between sequencing and imaging techniques for the discovery and validation of local molecular signaling mechanisms regulating synaptic development, plasticity, and maintenance in circuits.
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Affiliation(s)
| | - Colenso M. Speer
- Department of Biology, University of Maryland, College Park, MD, United States
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66
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Belardi B, Son S, Felce JH, Dustin ML, Fletcher DA. Cell-cell interfaces as specialized compartments directing cell function. Nat Rev Mol Cell Biol 2020; 21:750-764. [PMID: 33093672 DOI: 10.1038/s41580-020-00298-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2020] [Indexed: 12/14/2022]
Abstract
Cell-cell interfaces are found throughout multicellular organisms, from transient interactions between motile immune cells to long-lived cell-cell contacts in epithelia. Studies of immune cell interactions, epithelial cell barriers, neuronal contacts and sites of cell-cell fusion have identified a core set of features shared by cell-cell interfaces that critically control their function. Data from diverse cell types also show that cells actively and passively regulate the localization, strength, duration and cytoskeletal coupling of receptor interactions governing cell-cell signalling and physical connections between cells, indicating that cell-cell interfaces have a unique membrane organization that emerges from local molecular and cellular mechanics. In this Review, we discuss recent findings that support the emerging view of cell-cell interfaces as specialized compartments that biophysically constrain the arrangement and activity of their protein, lipid and glycan components. We also review how these biophysical features of cell-cell interfaces allow cells to respond with high selectivity and sensitivity to multiple inputs, serving as the basis for wide-ranging cellular functions. Finally, we consider how the unique properties of cell-cell interfaces present opportunities for therapeutic intervention.
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Affiliation(s)
- Brian Belardi
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA
| | - Sungmin Son
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA
| | | | | | - Daniel A Fletcher
- Department of Bioengineering & Biophysics Program, UC Berkeley, Berkeley, CA, USA.
- Division of Biological Systems & Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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67
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Spark A, Kitching A, Esteban-Ferrer D, Handa A, Carr AR, Needham LM, Ponjavic A, Santos AM, McColl J, Leterrier C, Davis SJ, Henriques R, Lee SF. vLUME: 3D virtual reality for single-molecule localization microscopy. Nat Methods 2020; 17:1097-1099. [PMID: 33046895 PMCID: PMC7612967 DOI: 10.1038/s41592-020-0962-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022]
Abstract
vLUME is a virtual reality software package designed to render large three-dimensional single-molecule localization microscopy datasets. vLUME features include visualization, segmentation, bespoke analysis of complex local geometries and exporting features. vLUME can perform complex analysis on real three-dimensional biological samples that would otherwise be impossible by using regular flat-screen visualization programs.
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Affiliation(s)
| | | | | | - Anoushka Handa
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | | | - Aleks Ponjavic
- School of Physics and Astronomy, University of Leeds, Leeds, UK
- School of Food Science and Nutrition, University of Leeds, Leeds, UK
| | - Ana Mafalda Santos
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - James McColl
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Simon J Davis
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Ricardo Henriques
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, UK.
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68
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Wiesner T, Bilodeau A, Bernatchez R, Deschênes A, Raulier B, De Koninck P, Lavoie-Cardinal F. Activity-Dependent Remodeling of Synaptic Protein Organization Revealed by High Throughput Analysis of STED Nanoscopy Images. Front Neural Circuits 2020; 14:57. [PMID: 33177994 PMCID: PMC7594516 DOI: 10.3389/fncir.2020.00057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 07/29/2020] [Indexed: 01/03/2023] Open
Abstract
The organization of proteins in the apposed nanodomains of pre- and postsynaptic compartments is thought to play a pivotal role in synaptic strength and plasticity. As such, the alignment between pre- and postsynaptic proteins may regulate, for example, the rate of presynaptic release or the strength of postsynaptic signaling. However, the analysis of these structures has mainly been restricted to subsets of synapses, providing a limited view of the diversity of synaptic protein cluster remodeling during synaptic plasticity. To characterize changes in the organization of synaptic nanodomains during synaptic plasticity over a large population of synapses, we combined STimulated Emission Depletion (STED) nanoscopy with a Python-based statistical object distance analysis (pySODA), in dissociated cultured hippocampal circuits exposed to treatments driving different forms of synaptic plasticity. The nanoscale organization, characterized in terms of coupling properties, of presynaptic (Bassoon, RIM1/2) and postsynaptic (PSD95, Homer1c) scaffold proteins was differently altered in response to plasticity-inducing stimuli. For the Bassoon - PSD95 pair, treatments driving synaptic potentiation caused an increase in their coupling probability, whereas a stimulus driving synaptic depression had an opposite effect. To enrich the characterization of the synaptic cluster remodeling at the population level, we applied unsupervised machine learning approaches to include selected morphological features into a multidimensional analysis. This combined analysis revealed a large diversity of synaptic protein cluster subtypes exhibiting differential activity-dependent remodeling, yet with common features depending on the expected direction of plasticity. The expanded palette of synaptic features revealed by our unbiased approach should provide a basis to further explore the widely diverse molecular mechanisms of synaptic plasticity.
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Affiliation(s)
| | | | | | | | | | - Paul De Koninck
- CERVO Brain Research Centre, Québec, QC, Canada.,Department of Biochemistry, Microbiology and Bioinformatics, Université Laval, Québec, QC, Canada
| | - Flavie Lavoie-Cardinal
- CERVO Brain Research Centre, Québec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
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69
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Grant SGN, Fransén E. The Synapse Diversity Dilemma: Molecular Heterogeneity Confounds Studies of Synapse Function. Front Synaptic Neurosci 2020; 12:590403. [PMID: 33132891 PMCID: PMC7561708 DOI: 10.3389/fnsyn.2020.590403] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/15/2020] [Indexed: 11/24/2022] Open
Abstract
Recent studies have shown an unexpectedly high degree of synapse diversity arising from molecular and morphological differences among individual synapses. Diverse synapse types are spatially distributed within individual dendrites, between different neurons, and across and between brain regions, producing the synaptome architecture of the brain. The spatial organization of synapse heterogeneity is important because the physiological activation of heterogeneous excitatory synapses produces a non-uniform spatial output of synaptic potentials, which confounds the interpretation of measurements obtained from population-averaging electrodes, optrodes and biochemical methods that lack single-synapse resolution. Population-averaging measurements cannot distinguish between changes in the composition of populations of synapses and changing synaptic physiology. Here we consider the implications of synapse diversity and its organization into synaptome architecture for studies of synapse physiology, plasticity, development and behavior, and for the interpretation of phenotypes arising from pharmacological and genetic perturbations. We conclude that prevailing models based on population-averaging measurements need reconsideration and that single-synapse resolution physiological recording methods are required to confirm or refute the major synaptic models of behavior.
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Affiliation(s)
- Seth G N Grant
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Erik Fransén
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden.,Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
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70
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Distance-dependent regulation of NMDAR nanoscale organization along hippocampal neuron dendrites. Proc Natl Acad Sci U S A 2020; 117:24526-24533. [PMID: 32929031 PMCID: PMC7533699 DOI: 10.1073/pnas.1922477117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hippocampal pyramidal neurons are characterized by a unique arborization subdivided in segregated dendritic domains receiving distinct excitatory synaptic inputs with specific properties and plasticity rules that shape their respective contributions to synaptic integration and action potential firing. Although the basal regulation and plastic range of proximal and distal synapses are known to be different, the composition and nanoscale organization of key synaptic proteins at these inputs remains largely elusive. Here we used superresolution imaging and single nanoparticle tracking in rat hippocampal neurons to unveil the nanoscale topography of native GluN2A- and GluN2B-NMDA receptors (NMDARs)-which play key roles in the use-dependent adaptation of glutamatergic synapses-along the dendritic arbor. We report significant changes in the nanoscale organization of GluN2B-NMDARs between proximal and distal dendritic segments, whereas the topography of GluN2A-NMDARs remains similar along the dendritic tree. Remarkably, the nanoscale organization of GluN2B-NMDARs at proximal segments depends on their interaction with calcium/calmodulin-dependent protein kinase II (CaMKII), which is not the case at distal segments. Collectively, our data reveal that the nanoscale organization of NMDARs changes along dendritic segments in a subtype-specific manner and is shaped by the interplay with CaMKII at proximal dendritic segments, shedding light on our understanding of the functional diversity of hippocampal glutamatergic synapses.
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71
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Bensussen S, Shankar S, Ching KH, Zemel D, Ta TL, Mount RA, Shroff SN, Gritton HJ, Fabris P, Vanbenschoten H, Beck C, Man HY, Han X. A Viral Toolbox of Genetically Encoded Fluorescent Synaptic Tags. iScience 2020; 23:101330. [PMID: 32674057 PMCID: PMC7363701 DOI: 10.1016/j.isci.2020.101330] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 04/18/2020] [Accepted: 06/26/2020] [Indexed: 01/16/2023] Open
Abstract
Fibronectin intrabodies generated with mRNA display (FingRs) are a recently developed tool for labeling excitatory or inhibitory synapses, with the benefit of not altering endogenous synaptic protein expression levels or synaptic transmission. Here, we generated a viral vector FingR toolbox that allows for multi-color, neuron-type-specific labeling of excitatory or inhibitory synapses in multiple brain regions. We screened various fluorophores, FingR fusion configurations, and transcriptional control regulations in adeno-associated virus (AAV) and retrovirus vector designs. We report the development of a red FingR variant and demonstrated dual labeling of excitatory and inhibitory synapses in the same cells. Furthermore, we developed cre-inducible FingR AAV variants and demonstrated their utility, finding that the density of inhibitory synapses in aspiny striatal cholinergic interneurons remained unchanged in response to dopamine depletion. Finally, we generated FingR retroviral vectors, which enabled us to track the development of excitatory and inhibitory synapses in hippocampal adult-born granule cells.
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Affiliation(s)
- Seth Bensussen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sneha Shankar
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kimberley H Ching
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Dana Zemel
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Tina L Ta
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Rebecca A Mount
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sanaya N Shroff
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Howard J Gritton
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Pierre Fabris
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | | | - Connor Beck
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Xue Han
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
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72
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Sauerbeck AD, Gangolli M, Reitz SJ, Salyards MH, Kim SH, Hemingway C, Gratuze M, Makkapati T, Kerschensteiner M, Holtzman DM, Brody DL, Kummer TT. SEQUIN Multiscale Imaging of Mammalian Central Synapses Reveals Loss of Synaptic Connectivity Resulting from Diffuse Traumatic Brain Injury. Neuron 2020; 107:257-273.e5. [PMID: 32392471 PMCID: PMC7381374 DOI: 10.1016/j.neuron.2020.04.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/04/2020] [Accepted: 04/11/2020] [Indexed: 02/07/2023]
Abstract
The brain's complex microconnectivity underlies its computational abilities and vulnerability to injury and disease. It has been challenging to illuminate the features of this synaptic network due to the small size and dense packing of its elements. Here, we describe a rapid, accessible super-resolution imaging and analysis workflow-SEQUIN-that quantifies central synapses in human tissue and animal models, characterizes their nanostructural and molecular features, and enables volumetric imaging of mesoscale synaptic networks without the production of large histological arrays. Using SEQUIN, we identify cortical synapse loss resulting from diffuse traumatic brain injury, a highly prevalent connectional disorder. Similar synapse loss is observed in three murine models of Alzheimer-related neurodegeneration, where SEQUIN mesoscale mapping identifies regional synaptic vulnerability. These results establish an easily implemented and robust nano-to-mesoscale synapse quantification and characterization method. They furthermore identify a shared mechanism-synaptopathy-between Alzheimer neurodegeneration and its best-established epigenetic risk factor, brain trauma.
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Affiliation(s)
- Andrew D Sauerbeck
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mihika Gangolli
- McKelvey School of Engineering, Washington University, St. Louis, MO 63130, USA; Currently, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Sydney J Reitz
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Maverick H Salyards
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Samuel H Kim
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Christopher Hemingway
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 82152, Germany
| | - Maud Gratuze
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tejaswi Makkapati
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Martin Kerschensteiner
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 82152, Germany; Munich Cluster of Systems Neurology (SyNergy), Munich 81377, Germany
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David L Brody
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Currently, Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Terrance T Kummer
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
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73
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Kokolaki ML, Fauquier A, Renner M. Molecular Crowding and Diffusion-Capture in Synapses. iScience 2020; 23:101382. [PMID: 32739837 PMCID: PMC7399191 DOI: 10.1016/j.isci.2020.101382] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/23/2020] [Accepted: 07/14/2020] [Indexed: 12/17/2022] Open
Abstract
Cell membranes often contain domains with important physiological functions. A typical example are neuronal synapses, whose capacity to capture receptors for neurotransmitters is central to neuronal functions. Receptors diffuse in the membrane until they are stabilized by interactions with stable elements, the scaffold. Single particle tracking experiments demonstrated that these interactions are rather weak and that lateral diffusion is strongly impaired in the post-synaptic membrane due to molecular crowding. We investigated how the distribution of scaffolding molecules and molecular crowding affect the capture of receptors. In particle-based Monte Carlo simulations, based on experimental data of molecular diffusion and organization, crowding enhanced the receptor-scaffold interaction but reduced the capture of new molecules. The distribution of scaffolding sites in several clusters reduced crowding and fostered the exchange of molecules accelerating synaptic plasticity. Synapses could switch between two regimes, becoming more stable or more plastic depending on the internal distribution of molecules. The good: molecular crowding enhances the interaction receptors-scaffold The bad: the exchange of molecules with extrasynaptic areas is reduced by crowding Molecular crowding helps synapses to be stable Nanoclusters of scaffold sites reduce crowding effects and favor synaptic plasticity
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Affiliation(s)
| | - Aurélien Fauquier
- Sorbonne Université UMR-S 1270 INSERM, Institut du Fer à Moulin (IFM), 75005 Paris, France
| | - Marianne Renner
- Sorbonne Université UMR-S 1270 INSERM, Institut du Fer à Moulin (IFM), 75005 Paris, France.
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74
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Cizeron M, Qiu Z, Koniaris B, Gokhale R, Komiyama NH, Fransén E, Grant SGN. A brainwide atlas of synapses across the mouse life span. Science 2020; 369:270-275. [PMID: 32527927 PMCID: PMC7115813 DOI: 10.1126/science.aba3163] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 05/19/2020] [Indexed: 01/03/2023]
Abstract
Synapses connect neurons together to form the circuits of the brain, and their molecular composition controls innate and learned behavior. We analyzed the molecular and morphological diversity of 5 billion excitatory synapses at single-synapse resolution across the mouse brain from birth to old age. A continuum of changes alters synapse composition in all brain regions across the life span. Expansion in synapse diversity produces differentiation of brain regions until early adulthood, and compositional changes cause dedifferentiation in old age. The spatiotemporal synaptome architecture of the brain potentially accounts for life-span transitions in intellectual ability, memory, and susceptibility to behavioral disorders.
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Affiliation(s)
- Mélissa Cizeron
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Institut NeuroMyoGène, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, 69008 Lyon, France
| | - Zhen Qiu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Babis Koniaris
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- School of Computing, Edinburgh Napier University, Edinburgh EH10 5DT, UK
| | - Ragini Gokhale
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Noboru H Komiyama
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Erik Fransén
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- Science for Life Laboratory, KTH Royal Institute of Technology, SE-171 65 Solna, Sweden
| | - Seth G N Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK.
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
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75
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Lafourcade CA, Fernández A, Ramírez JP, Corvalán K, Carrasco MÁ, Iturriaga A, Bátiz LF, Luarte A, Wyneken U. A Role for mir-26a in Stress: A Potential sEV Biomarker and Modulator of Excitatory Neurotransmission. Cells 2020; 9:cells9061364. [PMID: 32492799 PMCID: PMC7349773 DOI: 10.3390/cells9061364] [Citation(s) in RCA: 4] [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: 04/06/2020] [Revised: 05/21/2020] [Accepted: 05/27/2020] [Indexed: 01/08/2023] Open
Abstract
Stress is a widespread problem in today’s societies, having important consequences on brain function. Among the plethora of mechanisms involved in the stress response at the molecular level, the role of microRNAs (miRNAs) is beginning to be recognized. The control of gene expression by these noncoding RNAs makes them essential regulators of neuronal and synaptic physiology, and alterations in their levels have been associated with pathological conditions and mental disorders. In particular, the excitatory (i.e., glutamate-mediated) neurotransmission is importantly affected by stress. Here, we found that loss of miR-26a-5p (miR-26a henceforth) function in primary hippocampal neurons increased the frequency and amplitude of miniature excitatory currents, as well as the expression levels of the excitatory postsynaptic scaffolding protein PSD95. Incubation of primary hippocampal neurons with corticosterone downregulated miR-26a, an effect that mirrored our in vivo results, as miR-26a was downregulated in the hippocampus as well as in blood serum-derived small extracellular vesicles (sEVs) of rats exposed to two different stress paradigms by movement restriction (i.e., stress by restraint in cages or by complete immobilization in bags). Overall, these results suggest that miR-26a may be involved in the generalized stress response and that a stress-induced downregulation of miR-26a could have long-term effects on glutamate neurotransmission.
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Affiliation(s)
- Carlos Andrés Lafourcade
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
- Correspondence: (C.A.L.); (U.W.)
| | - Anllely Fernández
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
| | - Juan Pablo Ramírez
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
| | - Katherine Corvalán
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
| | - Miguel Ángel Carrasco
- Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Santiago PC 7620001, Chile;
| | - Andrés Iturriaga
- Instituto de Salud Poblacional, Facultad de Medicina, Universidad de Chile, Santiago PC 8380453, Chile;
| | - Luis Federico Bátiz
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
| | - Alejandro Luarte
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago PC 8380453, Chile;
| | - Ursula Wyneken
- Centro de Investigación e Innovación Biomédica (CIIB), Facultad de Medicina, Universidad de los Andes, Santiago PC 7620001, Chile; (A.F.); (J.P.R.); (K.C.); (L.F.B.)
- Correspondence: (C.A.L.); (U.W.)
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76
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Nanostructural Diversity of Synapses in the Mammalian Spinal Cord. Sci Rep 2020; 10:8189. [PMID: 32424125 PMCID: PMC7235094 DOI: 10.1038/s41598-020-64874-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/21/2020] [Indexed: 11/25/2022] Open
Abstract
Functionally distinct synapses exhibit diverse and complex organisation at molecular and nanoscale levels. Synaptic diversity may be dependent on developmental stage, anatomical locus and the neural circuit within which synapses reside. Furthermore, astrocytes, which align with pre and post-synaptic structures to form ‘tripartite synapses’, can modulate neural circuits and impact on synaptic organisation. In this study, we aimed to determine which factors impact the diversity of excitatory synapses throughout the lumbar spinal cord. We used PSD95-eGFP mice, to visualise excitatory postsynaptic densities (PSDs) using high-resolution and super-resolution microscopy. We reveal a detailed and quantitative map of the features of excitatory synapses in the lumbar spinal cord, detailing synaptic diversity that is dependent on developmental stage, anatomical region and whether associated with VGLUT1 or VGLUT2 terminals. We report that PSDs are nanostructurally distinct between spinal laminae and across age groups. PSDs receiving VGLUT1 inputs also show enhanced nanostructural complexity compared with those receiving VGLUT2 inputs, suggesting pathway-specific diversity. Finally, we show that PSDs exhibit greater nanostructural complexity when part of tripartite synapses, and we provide evidence that astrocytic activation enhances PSD95 expression. Taken together, these results provide novel insights into the regulation and diversification of synapses across functionally distinct spinal regions and advance our general understanding of the ‘rules’ governing synaptic nanostructural organisation.
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77
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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78
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Dosemeci A, Tao-Cheng JH, Bakly V, Reese TS. Postsynaptic densities fragment into subcomplexes upon sonication. Mol Brain 2019; 12:72. [PMID: 31439005 PMCID: PMC6704671 DOI: 10.1186/s13041-019-0491-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/09/2019] [Indexed: 11/23/2022] Open
Abstract
Postsynaptic density (PSD) fractions were isolated from rat forebrain and sonicated. Pellets from sonicated samples examined by electron microscopy revealed particles with an electron density similar to PSDs that appeared to be fragments of PSDs. Immuno-gold labeling confirmed that some of these contained PSD-95 and/or SynGAP. Biochemical analysis of supernatant and pellet fractions from sonicated samples showed almost complete recovery of several major PSD components (SynGAP, PSD-95, Shank3, Homer and Glutamate receptors) in the pellet, while the supernatant contained known contaminants of PSD fractions, such as glial acidic fibrillary protein and neurofilament protein, as well as actin and α-actinin, indicating susceptibility of these cytoskeletal elements to mechanical disruption. Size distributions of particulate material in control and sonicated samples were clearly different, with particles in the 40–90 nm range observed only in sonicated samples. Fragmentation of the PSD into subcomplexes containing major constituents suggests a patchwork structure consisting of weakly bound modules, that can be readily dissociated from each other through mechanical disruption. Modular organization and weak association between modules would endow the PSD with lateral structural flexibility.
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Affiliation(s)
- Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - Jung-Hwa Tao-Cheng
- EM Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Valerie Bakly
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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79
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Yang X, Specht CG. Subsynaptic Domains in Super-Resolution Microscopy: The Treachery of Images. Front Mol Neurosci 2019; 12:161. [PMID: 31312120 PMCID: PMC6614521 DOI: 10.3389/fnmol.2019.00161] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 06/12/2019] [Indexed: 12/13/2022] Open
Abstract
The application of super-resolution optical microscopy to investigating synaptic structures has revealed a highly heterogeneous and variable intra-synaptic organization. Dense subsynaptic protein assemblies named subsynaptic domains or SSDs have been proposed as structural units that regulate the efficacy of neuronal transmission. However, an in-depth characterization of SSDs has been hampered by technical limitations of super-resolution microscopy of synapses, namely the stochasticity of the signals during the imaging procedures and the variability of the synaptic structures. Here, we synthetize the available evidence for the existence of SSDs at central synapses, as well as the possible functional relevance of SSDs. In particular, we discuss the possible regulation of co-transmission at mixed inhibitory synapses as a consequence of the subsynaptic distribution of glycine receptors (GlyRs) and GABAA receptors (GABAARs). LAY ABSTRACT Super-resolution imaging strategies bypass the resolution limit of conventional optical microscopy and have given new insights into the distribution of proteins at synapses in the central nervous system. Neurotransmitter receptors and scaffold proteins appear to occupy specialized locations within synapses that we refer to as subsynaptic domains or SSDs. Interestingly, these SSDs are highly dynamic and their formation seems to be related to the remodeling of synapses during synaptic plasticity. It was also shown that SSDs of pre-and post-synaptic proteins are aligned in so-called nanocolumns, highlighting the role of SSDs in the regulation of synaptic transmission. Despite recent advances, however, the detection of SSDs with super-resolution microscopy remains difficult due to the inherent technical limitations of these approaches that are discussed in this review article.
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Affiliation(s)
- Xiaojuan Yang
- École Normale Supérieure, PSL Research University, CNRS, Inserm, Institute of Biology (IBENS), Paris, France
| | - Christian G Specht
- École Normale Supérieure, PSL Research University, CNRS, Inserm, Institute of Biology (IBENS), Paris, France
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80
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Metzbower SR, Joo Y, Benavides DR, Blanpied TA. Properties of Individual Hippocampal Synapses Influencing NMDA-Receptor Activation by Spontaneous Neurotransmission. eNeuro 2019; 6:ENEURO.0419-18.2019. [PMID: 31110134 PMCID: PMC6541874 DOI: 10.1523/eneuro.0419-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 05/05/2019] [Accepted: 05/12/2019] [Indexed: 12/14/2022] Open
Abstract
NMDA receptor (NMDAR) activation is critical for maintenance and modification of synapse strength. Specifically, NMDAR activation by spontaneous glutamate release has been shown to mediate some forms of synaptic plasticity as well as synaptic development. Interestingly, there is evidence that within individual synapses each release mode may be segregated such that postsynaptically there are distinct pools of responsive receptors. To examine potential regulators of NMDAR activation because of spontaneous glutamate release in cultured hippocampal neurons, we used GCaMP6f imaging at single synapses in concert with confocal and super-resolution imaging. Using these single-spine approaches, we found that Ca2+ entry activated by spontaneous release tends to be carried by GluN2B-NMDARs. Additionally, the amount of NMDAR activation varies greatly both between synapses and within synapses, and is unrelated to spine and synapse size, but does correlate loosely with synapse distance from the soma. Despite the critical role of spontaneous activation of NMDARs in maintaining synaptic function, their activation seems to be controlled factors other than synapse size or synapse distance from the soma. It is most likely that NMDAR activation by spontaneous release influenced variability in subsynaptic receptor position, release site position, vesicle content, and channel properties. Therefore, spontaneous activation of NMDARs appears to be regulated distinctly from other receptor types, notably AMPARs, within individual synapses.
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Affiliation(s)
| | - Yuyoung Joo
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - David R Benavides
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
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81
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Guo H, Xie Q, Cui J, Xu D, Deji C, Chen Y, Wang Y, Lai J. Naloxone reversed cognitive impairments induced by repeated morphine under heavy perceptual load in the 5-choice serial reaction time task. J Neurosci Res 2019; 97:1051-1065. [PMID: 31081159 DOI: 10.1002/jnr.24427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 02/28/2019] [Accepted: 03/18/2019] [Indexed: 12/23/2022]
Abstract
Repeated opioids abuse may produce long-lasting and complicated cognitive deficits in individuals. Naloxone is a typical mu-opioid receptor antagonist widely used in clinical treatment for opioid overdose and opioid abuse. However, it remains unclear whether naloxone affects morphine-induced cognitive deficits. Using the 5-choice serial reaction time task (5-CSRTT), the present study investigated cognitive profiles including attention, impulsivity, compulsivity, and processing speed in repeated morphine-treated mice. Repeated morphine administration (10 mg/kg, i.p.) induced complex cognitive changes including decreased attention and increased impulsivity, compulsivity, processing speed. Systemic naloxone administration (5 mg/kg, i.p.) reversed these cognitive changes under the heavy perceptual load in 5-CSRTT. Using the novel object recognition (NOR), Y-maze and open-field test (OFT), the present study investigated the memory ability and locomotor activity. Naloxone reversed the effect of morphine on recognition memory and locomotion but had no effect on working memory. In addition, repeated morphine administration decreased the expression of postsynaptic density protein 95 (PSD95) and cAMP response element binding protein (CREB) phosphorylation in the prefrontal cortex (PFC) and hippocampus (HIP), and these effects were significantly reversed by naloxone in PFC. Our study suggests that repeated exposure to morphine affects multiple cognitive aspects and impairs synaptic functions. Systemic naloxone treatment reverses the mu-opioids-induced cognitive changes, especially under the heavy perceptual load, possibly by restoring the synaptic dysfunctions.
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Affiliation(s)
- Hao Guo
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Qiaoli Xie
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Jingjing Cui
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Dan Xu
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Cuola Deji
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Yuanyuan Chen
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Yunpeng Wang
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China
| | - Jianghua Lai
- College of Forensic Science, Xi'an Jiaotong University, Xi'an, China.,Key Laboratory of Ministry of Public Health for Forensic Science, Xi'an, China
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82
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Feng Z, Chen X, Zeng M, Zhang M. Phase separation as a mechanism for assembling dynamic postsynaptic density signalling complexes. Curr Opin Neurobiol 2018; 57:1-8. [PMID: 30599311 DOI: 10.1016/j.conb.2018.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 12/04/2018] [Indexed: 10/27/2022]
Abstract
The postsynaptic density (PSD) is an electron dense, semi-membrane bound compartment that lies beneath postsynaptic membranes. This region is densely packed with thousands of proteins that are involved in extensive interactions. During synaptic plasticity, the PSD undergoes changes in size and composition along with changes in synaptic strength that lead to long term potentiation (LTP) or depression (LTD). It is therefore essential to understand the organization principles underlying PSD assembly and rearrangement. Here, we review exciting new findings from recent in vitro reconstitution studies and propose a hypothesis that liquid-liquid phase separation mediates PSD formation and regulation. We also discuss how the properties of PSD formed via phase separation might contribute to the biological functions observed from decades of researches. Finally, we highlight unanswered questions regarding PSD organization and how in vitro reconstitution systems may help to answer these questions in the coming years.
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Affiliation(s)
- Zhe Feng
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xudong Chen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Menglong Zeng
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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83
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Grant SGN. Synapse molecular complexity and the plasticity behaviour problem. Brain Neurosci Adv 2018; 2:2398212818810685. [PMID: 32166154 PMCID: PMC7058196 DOI: 10.1177/2398212818810685] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Indexed: 01/06/2023] Open
Abstract
Synapses are the hallmark of brain complexity and have long been thought of as simple connectors between neurons. We are now in an era in which we know the full complement of synapse proteins and this has created an existential crisis because the molecular complexity far exceeds the requirements of most simple models of synaptic function. Studies of the organisation of proteome complexity and its evolution provide surprising new insights that challenge existing dogma and promote the development of new theories about the origins and role of synapses in behaviour. The postsynaptic proteome of excitatory synapses is a structure with high molecular complexity and sophisticated computational properties that is disrupted in over 130 brain diseases. A key goal of 21st-century neuroscience is to develop comprehensive molecular datasets on the brain and develop theories that explain the molecular basis of behaviour.
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Affiliation(s)
- Seth G N Grant
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
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84
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Kellermayer B, Ferreira JS, Dupuis J, Levet F, Grillo-Bosch D, Bard L, Linarès-Loyez J, Bouchet D, Choquet D, Rusakov DA, Bon P, Sibarita JB, Cognet L, Sainlos M, Carvalho AL, Groc L. Differential Nanoscale Topography and Functional Role of GluN2-NMDA Receptor Subtypes at Glutamatergic Synapses. Neuron 2018; 100:106-119.e7. [PMID: 30269991 DOI: 10.1016/j.neuron.2018.09.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 04/26/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
NMDA receptors (NMDARs) play key roles in the use-dependent adaptation of glutamatergic synapses underpinning memory formation. In the forebrain, these plastic processes involve the varied contributions of GluN2A- and GluN2B-containing NMDARs that have different signaling properties. Although the molecular machinery of synaptic NMDAR trafficking has been under scrutiny, the postsynaptic spatial organization of these two receptor subtypes has remained elusive. Here, we used super-resolution imaging of NMDARs in rat hippocampal synapses to unveil the nanoscale topography of native GluN2A- and GluN2B-NMDARs. Both subtypes were found to be organized in separate nanodomains that vary over the course of development. Furthermore, GluN2A- and GluN2B-NMDAR nanoscale organizations relied on distinct regulatory mechanisms. Strikingly, the selective rearrangement of GluN2A- and GluN2B-NMDARs, with no overall change in NMDAR current amplitude, allowed bi-directional tuning of synaptic LTP. Thus, GluN2A- and GluN2B-NMDAR nanoscale organizations are differentially regulated and seem to involve distinct signaling complexes during synaptic adaptation.
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Affiliation(s)
- Blanka Kellermayer
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.
| | - Joana S Ferreira
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Julien Dupuis
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Florian Levet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNRS, Bordeaux Imaging Center UMS 3420, 33000 Bordeaux, France
| | - Dolors Grillo-Bosch
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Lucie Bard
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; UCL Institute of Neurology, University College London, London, UK
| | - Jeanne Linarès-Loyez
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Delphine Bouchet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Daniel Choquet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNRS, Bordeaux Imaging Center UMS 3420, 33000 Bordeaux, France
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, UK
| | - Pierre Bon
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Jean-Baptiste Sibarita
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Laurent Cognet
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Matthieu Sainlos
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Ana Luisa Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Laurent Groc
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France.
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85
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Malavasi ELV, Economides KD, Grünewald E, Makedonopoulou P, Gautier P, Mackie S, Murphy LC, Murdoch H, Crummie D, Ogawa F, McCartney DL, O'Sullivan ST, Burr K, Torrance HS, Phillips J, Bonneau M, Anderson SM, Perry P, Pearson M, Constantinides C, Davidson-Smith H, Kabiri M, Duff B, Johnstone M, Polites HG, Lawrie SM, Blackwood DH, Semple CA, Evans KL, Didier M, Chandran S, McIntosh AM, Price DJ, Houslay MD, Porteous DJ, Millar JK. DISC1 regulates N-methyl-D-aspartate receptor dynamics: abnormalities induced by a Disc1 mutation modelling a translocation linked to major mental illness. Transl Psychiatry 2018; 8:184. [PMID: 30190480 PMCID: PMC6127284 DOI: 10.1038/s41398-018-0228-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 07/16/2018] [Indexed: 01/01/2023] Open
Abstract
The neuromodulatory gene DISC1 is disrupted by a t(1;11) translocation that is highly penetrant for schizophrenia and affective disorders, but how this translocation affects DISC1 function is incompletely understood. N-methyl-D-aspartate receptors (NMDAR) play a central role in synaptic plasticity and cognition, and are implicated in the pathophysiology of schizophrenia through genetic and functional studies. We show that the NMDAR subunit GluN2B complexes with DISC1-associated trafficking factor TRAK1, while DISC1 interacts with the GluN1 subunit and regulates dendritic NMDAR motility in cultured mouse neurons. Moreover, in the first mutant mouse that models DISC1 disruption by the translocation, the pool of NMDAR transport vesicles and surface/synaptic NMDAR expression are increased. Since NMDAR cell surface/synaptic expression is tightly regulated to ensure correct function, these changes in the mutant mouse are likely to affect NMDAR signalling and synaptic plasticity. Consistent with these observations, RNASeq analysis of the translocation carrier-derived human neurons indicates abnormalities of excitatory synapses and vesicle dynamics. RNASeq analysis of the human neurons also identifies many differentially expressed genes previously highlighted as putative schizophrenia and/or depression risk factors through large-scale genome-wide association and copy number variant studies, indicating that the translocation triggers common disease pathways that are shared with unrelated psychiatric patients. Altogether, our findings suggest that translocation-induced disease mechanisms are likely to be relevant to mental illness in general, and that such disease mechanisms include altered NMDAR dynamics and excitatory synapse function. This could contribute to the cognitive disorders displayed by translocation carriers.
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Affiliation(s)
- Elise L V Malavasi
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | | | - Ellen Grünewald
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Paraskevi Makedonopoulou
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Philippe Gautier
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Shaun Mackie
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Laura C Murphy
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Hannah Murdoch
- Molecular Pharmacology Group, Wolfson Building, Institute of Neuroscience and Psychology, The University of Glasgow, University Avenue, Glasgow, UK
| | - Darragh Crummie
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Fumiaki Ogawa
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Daniel L McCartney
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Shane T O'Sullivan
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Karen Burr
- Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, UK
| | - Helen S Torrance
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Jonathan Phillips
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Marion Bonneau
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Susan M Anderson
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Paul Perry
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Matthew Pearson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Costas Constantinides
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Hazel Davidson-Smith
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Mostafa Kabiri
- Translational In Vivo Models at Sanofi, Frankfurt, Germany
| | - Barbara Duff
- Division of Psychiatry, The University of Edinburgh, Edinburgh, UK
| | - Mandy Johnstone
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
- Division of Psychiatry, The University of Edinburgh, Edinburgh, UK
| | | | - Stephen M Lawrie
- Division of Psychiatry, The University of Edinburgh, Edinburgh, UK
| | | | - Colin A Semple
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Kathryn L Evans
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - Michel Didier
- Translational Sciences at Sanofi, Chilly-Mazarin, France
| | | | | | - David J Price
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, UK
| | - Miles D Houslay
- School of Cancer and Pharmaceutical Sciences, King's College London, London, UK
| | - David J Porteous
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK
| | - J Kirsty Millar
- Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Edinburgh, UK.
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86
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Dynamics, nanoscale organization, and function of synaptic adhesion molecules. Mol Cell Neurosci 2018; 91:95-107. [DOI: 10.1016/j.mcn.2018.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 04/12/2018] [Accepted: 04/13/2018] [Indexed: 12/13/2022] Open
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87
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Scheefhals N, MacGillavry HD. Functional organization of postsynaptic glutamate receptors. Mol Cell Neurosci 2018; 91:82-94. [PMID: 29777761 PMCID: PMC6276983 DOI: 10.1016/j.mcn.2018.05.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/16/2018] [Accepted: 05/07/2018] [Indexed: 01/28/2023] Open
Abstract
Glutamate receptors are the most abundant excitatory neurotransmitter receptors in the brain, responsible for mediating the vast majority of excitatory transmission in neuronal networks. The AMPA- and NMDA-type ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that mediate the fast synaptic responses, while metabotropic glutamate receptors (mGluRs) are coupled to downstream signaling cascades that act on much slower timescales. These functionally distinct receptor sub-types are co-expressed at individual synapses, allowing for the precise temporal modulation of postsynaptic excitability and plasticity. Intriguingly, these receptors are differentially distributed with respect to the presynaptic release site. While iGluRs are enriched in the core of the synapse directly opposing the release site, mGluRs reside preferentially at the border of the synapse. As such, to understand the differential contribution of these receptors to synaptic transmission, it is important to not only consider their signaling properties, but also the mechanisms that control the spatial segregation of these receptor types within synapses. In this review, we will focus on the mechanisms that control the organization of glutamate receptors at the postsynaptic membrane with respect to the release site, and discuss how this organization could regulate synapse physiology.
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Affiliation(s)
- Nicky Scheefhals
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Harold D MacGillavry
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
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88
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Masch JM, Steffens H, Fischer J, Engelhardt J, Hubrich J, Keller-Findeisen J, D'Este E, Urban NT, Grant SGN, Sahl SJ, Kamin D, Hell SW. Robust nanoscopy of a synaptic protein in living mice by organic-fluorophore labeling. Proc Natl Acad Sci U S A 2018; 115:E8047-E8056. [PMID: 30082388 PMCID: PMC6112726 DOI: 10.1073/pnas.1807104115] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Extending superresolution fluorescence microscopy to living animals has remained a challenging frontier ever since the first demonstration of STED (stimulated emission depletion) nanoscopy in the mouse visual cortex. The use of fluorescent proteins (FPs) in in vivo STED analyses has been limiting available fluorescence photon budgets and attainable image contrasts, in particular for far-red FPs. This has so far precluded the definition of subtle details in protein arrangements at sufficient signal-to-noise ratio. Furthermore, imaging with longer wavelengths holds promise for reducing photostress. Here, we demonstrate that a strategy based on enzymatic self-labeling of the HaloTag fusion protein by high-performance synthetic fluorophore labels provides a robust avenue to superior in vivo analysis with STED nanoscopy in the far-red spectral range. We illustrate our approach by mapping the nanoscale distributions of the abundant scaffolding protein PSD95 at the postsynaptic membrane of excitatory synapses in living mice. With silicon-rhodamine as the reporter fluorophore, we present imaging with high contrast and low background down to ∼70-nm lateral resolution in the visual cortex at ≤25-µm depth. This approach allowed us to identify and characterize the diversity of PSD95 scaffolds in vivo. Besides small round/ovoid shapes, a substantial fraction of scaffolds exhibited a much more complex spatial organization. This highly inhomogeneous, spatially extended PSD95 distribution within the disk-like postsynaptic density, featuring intricate perforations, has not been highlighted in cell- or tissue-culture experiments. Importantly, covisualization of the corresponding spine morphologies enabled us to contextualize the diverse PSD95 patterns within synapses of different orientations and sizes.
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Affiliation(s)
- Jennifer-Magdalena Masch
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
| | - Heinz Steffens
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Joachim Fischer
- Optical Nanoscopy Division, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Johann Engelhardt
- Optical Nanoscopy Division, German Cancer Research Center, 69120 Heidelberg, Germany
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Jasmine Hubrich
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Jan Keller-Findeisen
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Elisa D'Este
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Nicolai T Urban
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - Steffen J Sahl
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Dirk Kamin
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
| | - Stefan W Hell
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37073 Göttingen, Germany
- Optical Nanoscopy Division, German Cancer Research Center, 69120 Heidelberg, Germany
- Department of Optical Nanoscopy, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
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89
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Zhu F, Cizeron M, Qiu Z, Benavides-Piccione R, Kopanitsa MV, Skene NG, Koniaris B, DeFelipe J, Fransén E, Komiyama NH, Grant SGN. Architecture of the Mouse Brain Synaptome. Neuron 2018; 99:781-799.e10. [PMID: 30078578 PMCID: PMC6117470 DOI: 10.1016/j.neuron.2018.07.007] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 06/22/2018] [Accepted: 07/03/2018] [Indexed: 12/11/2022]
Abstract
Synapses are found in vast numbers in the brain and contain complex proteomes. We developed genetic labeling and imaging methods to examine synaptic proteins in individual excitatory synapses across all regions of the mouse brain. Synapse catalogs were generated from the molecular and morphological features of a billion synapses. Each synapse subtype showed a unique anatomical distribution, and each brain region showed a distinct signature of synapse subtypes. Whole-brain synaptome cartography revealed spatial architecture from dendritic to global systems levels and previously unknown anatomical features. Synaptome mapping of circuits showed correspondence between synapse diversity and structural and functional connectomes. Behaviorally relevant patterns of neuronal activity trigger spatiotemporal postsynaptic responses sensitive to the structure of synaptome maps. Areas controlling higher cognitive function contain the greatest synapse diversity, and mutations causing cognitive disorders reorganized synaptome maps. Synaptome technology and resources have wide-ranging application in studies of the normal and diseased brain.
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Affiliation(s)
- Fei Zhu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UCL Institute of Neurology, Queen Square, WC1N 3BG London, UK
| | - Mélissa Cizeron
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; Institut NeuroMyoGène, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, 69008 Lyon, France
| | - Zhen Qiu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ruth Benavides-Piccione
- Instituto Cajal (CSIC) 28002 Madrid, Centro de Tecnología Biomédica (UPM) 28223 Madrid; CIBERNED, ISCIII, 28031 Madrid, Spain
| | - Maksym V Kopanitsa
- Synome Ltd, Babraham Research Campus, Cambridge CB22 3AT, UK; UK Dementia Research Institute, Imperial College London, London W12 0NN, UK
| | - Nathan G Skene
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UCL Institute of Neurology, Queen Square, WC1N 3BG London, UK; Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Babis Koniaris
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Javier DeFelipe
- Instituto Cajal (CSIC) 28002 Madrid, Centro de Tecnología Biomédica (UPM) 28223 Madrid; CIBERNED, ISCIII, 28031 Madrid, Spain
| | - Erik Fransén
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
| | - Noboru H Komiyama
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Seth G N Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK.
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90
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Chen H, Tang AH, Blanpied TA. Subsynaptic spatial organization as a regulator of synaptic strength and plasticity. Curr Opin Neurobiol 2018; 51:147-153. [PMID: 29902592 PMCID: PMC6295321 DOI: 10.1016/j.conb.2018.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 01/03/2023]
Abstract
Synapses differ markedly in their performance, even amongst those on a single neuron. The mechanisms that drive this functional diversification are of great interest because they enable adaptive behaviors and are targets of pathology. Considerable effort has focused on elucidating mechanisms of plasticity that involve changes to presynaptic release probability and the number of postsynaptic receptors. However, recent work is clarifying that nanoscale organization of the proteins within glutamatergic synapses impacts synapse function. Specifically, active zone scaffold proteins form nanoclusters that define sites of neurotransmitter release, and these sites align transsynaptically with clustered postsynaptic receptors. These nanostructural characteristics raise numerous possibilities for how synaptic plasticity could be expressed.
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Affiliation(s)
- Haiwen Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland Baltimore, Baltimore, MD 21201, USA; Medical Scientist Training Program, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ai-Hui Tang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland Baltimore, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland Baltimore, Baltimore, MD 21201, USA.
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91
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Fernández E, Collins MO, Frank RAW, Zhu F, Kopanitsa MV, Nithianantharajah J, Lemprière SA, Fricker D, Elsegood KA, McLaughlin CL, Croning MDR, Mclean C, Armstrong JD, Hill WD, Deary IJ, Cencelli G, Bagni C, Fromer M, Purcell SM, Pocklington AJ, Choudhary JS, Komiyama NH, Grant SGN. Arc Requires PSD95 for Assembly into Postsynaptic Complexes Involved with Neural Dysfunction and Intelligence. Cell Rep 2018; 21:679-691. [PMID: 29045836 PMCID: PMC5656750 DOI: 10.1016/j.celrep.2017.09.045] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 08/03/2017] [Accepted: 09/13/2017] [Indexed: 12/12/2022] Open
Abstract
Arc is an activity-regulated neuronal protein, but little is known about its interactions, assembly into multiprotein complexes, and role in human disease and cognition. We applied an integrated proteomic and genetic strategy by targeting a tandem affinity purification (TAP) tag and Venus fluorescent protein into the endogenous Arc gene in mice. This allowed biochemical and proteomic characterization of native complexes in wild-type and knockout mice. We identified many Arc-interacting proteins, of which PSD95 was the most abundant. PSD95 was essential for Arc assembly into 1.5-MDa complexes and activity-dependent recruitment to excitatory synapses. Integrating human genetic data with proteomic data showed that Arc-PSD95 complexes are enriched in schizophrenia, intellectual disability, autism, and epilepsy mutations and normal variants in intelligence. We propose that Arc-PSD95 postsynaptic complexes potentially affect human cognitive function. TAP tag and purification of endogenous Arc protein complexes from the mouse brain PSD95 is the major Arc binding protein, and both assemble into 1.5-MDa supercomplexes PSD95 is essential for recruitment of Arc to synapses Mutations and genetic variants in Arc-PSD95 are linked to cognition
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Affiliation(s)
- Esperanza Fernández
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), and VIB Center for the Biology of Disease, Leuven, Belgium
| | - Mark O Collins
- Proteomic Mass Spectrometry, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - René A W Frank
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Fei Zhu
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Maksym V Kopanitsa
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Synome Ltd., Moneta Building, Babraham Research Campus, Cambridge, UK
| | - Jess Nithianantharajah
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Sarah A Lemprière
- Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - David Fricker
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Synome Ltd., Moneta Building, Babraham Research Campus, Cambridge, UK
| | - Kathryn A Elsegood
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Catherine L McLaughlin
- Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Mike D R Croning
- Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Colin Mclean
- School of Informatics, Institute for Adaptive and Neural Computation, University of Edinburgh, UK
| | - J Douglas Armstrong
- School of Informatics, Institute for Adaptive and Neural Computation, University of Edinburgh, UK
| | - W David Hill
- Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, UK
| | - Ian J Deary
- Centre for Cognitive Ageing and Cognitive Epidemiology, Department of Psychology, University of Edinburgh, UK
| | - Giulia Cencelli
- KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), and VIB Center for the Biology of Disease, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Claudia Bagni
- KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), and VIB Center for the Biology of Disease, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Menachem Fromer
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Psychiatric Genomics, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Shaun M Purcell
- Division of Psychiatric Genomics, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andrew J Pocklington
- Institute of Psychological Medicine & Clinical Neurosciences, University of Cardiff, Cardiff, Wales, UK
| | - Jyoti S Choudhary
- Proteomic Mass Spectrometry, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Noboru H Komiyama
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK
| | - Seth G N Grant
- Genes to Cognition Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK; Genes to Cognition Programme, Centre for Clinical Brain Science, University of Edinburgh, Edinburgh, UK.
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92
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Synaptic nanomodules underlie the organization and plasticity of spine synapses. Nat Neurosci 2018; 21:671-682. [PMID: 29686261 PMCID: PMC5920789 DOI: 10.1038/s41593-018-0138-9] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/27/2018] [Indexed: 02/05/2023]
Abstract
Experience results in long-lasting changes in dendritic spine size, yet how the molecular architecture of the synapse responds to plasticity remains poorly understood. Here a combined approach of multicolor stimulated emission depletion microscopy (STED) and confocal imaging in rat and mouse demonstrates that structural plasticity is linked to the addition of unitary synaptic nanomodules to spines. Spine synapses in vivo and in vitro contain discrete and aligned subdiffraction modules of pre- and postsynaptic proteins whose number scales linearly with spine size. Live-cell time-lapse super-resolution imaging reveals that NMDA receptor-dependent increases in spine size are accompanied both by enhanced mobility of pre- and postsynaptic modules that remain aligned with each other and by a coordinated increase in the number of nanomodules. These findings suggest a simplified model for experience-dependent structural plasticity relying on an unexpectedly modular nanomolecular architecture of synaptic proteins.
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93
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Horner AE, McLaughlin CL, Afinowi NO, Bussey TJ, Saksida LM, Komiyama NH, Grant SGN, Kopanitsa MV. Enhanced cognition and dysregulated hippocampal synaptic physiology in mice with a heterozygous deletion of PSD-95. Eur J Neurosci 2018; 47:164-176. [DOI: 10.1111/ejn.13792] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/29/2017] [Accepted: 11/29/2017] [Indexed: 01/25/2023]
Affiliation(s)
| | - Catherine L. McLaughlin
- Genes to Cognition Programme; Centre for Clinical Brain Sciences; University of Edinburgh; Edinburgh UK
| | | | - Timothy J. Bussey
- Department of Psychology; University of Cambridge; Cambridge UK
- The MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute; University of Cambridge; Cambridge UK
- Molecular Medicine Research Group; Robarts Research Institute; London ON Canada
- Department of Physiology and Pharmacology; Schulich School of Medicine & Dentistry; Western University; London ON Canada
| | - Lisa M. Saksida
- Department of Psychology; University of Cambridge; Cambridge UK
- The MRC and Wellcome Trust Behavioural and Clinical Neuroscience Institute; University of Cambridge; Cambridge UK
- Molecular Medicine Research Group; Robarts Research Institute; London ON Canada
- Department of Physiology and Pharmacology; Schulich School of Medicine & Dentistry; Western University; London ON Canada
| | - Noboru H. Komiyama
- Genes to Cognition Programme; Centre for Clinical Brain Sciences; University of Edinburgh; Edinburgh UK
| | - Seth G. N. Grant
- Genes to Cognition Programme; Centre for Clinical Brain Sciences; University of Edinburgh; Edinburgh UK
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94
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Wegner W, Mott AC, Grant SGN, Steffens H, Willig KI. In vivo STED microscopy visualizes PSD95 sub-structures and morphological changes over several hours in the mouse visual cortex. Sci Rep 2018; 8:219. [PMID: 29317733 PMCID: PMC5760696 DOI: 10.1038/s41598-017-18640-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/14/2017] [Indexed: 12/23/2022] Open
Abstract
The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures; most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse.
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Affiliation(s)
- Waja Wegner
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Alexander C Mott
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Seth G N Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, Chancellor's Building, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Heinz Steffens
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Katrin I Willig
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany. .,Collaborative Research Center 889, University of Göttingen, Göttingen, Germany. .,Max Planck Institute of Experimental Medicine, Göttingen, Germany.
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95
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Lippert A, Janeczek AA, Fürstenberg A, Ponjavic A, Moerner WE, Nusse R, Helms JA, Evans ND, Lee SF. Single-Molecule Imaging of Wnt3A Protein Diffusion on Living Cell Membranes. Biophys J 2017; 113:2762-2767. [PMID: 29262368 PMCID: PMC5925569 DOI: 10.1016/j.bpj.2017.08.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/13/2017] [Accepted: 08/02/2017] [Indexed: 01/31/2023] Open
Abstract
Wnt proteins are secreted, hydrophobic, lipidated proteins found in all animals that play essential roles in development and disease. Lipid modification is thought to facilitate the interaction of the protein with its receptor, Frizzled, but may also regulate the transport of Wnt protein and its localization at the cell membrane. Here, by employing single-molecule fluorescence techniques, we show that Wnt proteins associate with and diffuse on the plasma membranes of living cells in the absence of any receptor binding. We find that labeled Wnt3A transiently and dynamically associates with the membranes of Drosophila Schneider 2 cells, diffuses with Brownian kinetics on flattened membranes and on cellular protrusions, and does not transfer between cells in close contact. In S2 receptor-plus (S2R+) cells, which express Frizzled receptors, membrane diffusion rate is reduced and membrane residency time is increased. These results provide direct evidence of Wnt3A interaction with living cell membranes, and represent, to our knowledge, a new system for investigating the dynamics of Wnt transport.
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Affiliation(s)
- Anna Lippert
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Agnieszka A Janeczek
- Centre for Human Development, Stem Cells and Regeneration, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Alexandre Fürstenberg
- Department of Chemistry, Stanford University, Palo Alto, California; Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, Genève, Switzerland
| | - Aleks Ponjavic
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - W E Moerner
- Department of Chemistry, Stanford University, Palo Alto, California
| | - Roel Nusse
- Department of Developmental Biology, Stanford University, Palo Alto, California
| | - Jill A Helms
- Division of Plastic and Reconstructive Surgery, Stanford University, Stanford, California
| | - Nicholas D Evans
- Centre for Human Development, Stem Cells and Regeneration, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Department of Chemistry, Stanford University, Palo Alto, California.
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96
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Roy M, Sorokina O, Skene N, Simonnet C, Mazzo F, Zwart R, Sher E, Smith C, Armstrong JD, Grant SGN. Proteomic analysis of postsynaptic proteins in regions of the human neocortex. Nat Neurosci 2017; 21:130-138. [DOI: 10.1038/s41593-017-0025-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 10/22/2017] [Indexed: 12/21/2022]
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97
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Liu KKL, Hagan MF, Lisman JE. Gradation (approx. 10 size states) of synaptic strength by quantal addition of structural modules. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0328. [PMID: 28093559 DOI: 10.1098/rstb.2016.0328] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2016] [Indexed: 12/31/2022] Open
Abstract
Memory storage involves activity-dependent strengthening of synaptic transmission, a process termed long-term potentiation (LTP). The late phase of LTP is thought to encode long-term memory and involves structural processes that enlarge the synapse. Hence, understanding how synapse size is graded provides fundamental information about the information storage capability of synapses. Recent work using electron microscopy (EM) to quantify synapse dimensions has suggested that synapses may structurally encode as many as 26 functionally distinct states, which correspond to a series of proportionally spaced synapse sizes. Other recent evidence using super-resolution microscopy has revealed that synapses are composed of stereotyped nanoclusters of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and scaffolding proteins; furthermore, synapse size varies linearly with the number of nanoclusters. Here we have sought to develop a model of synapse structure and growth that is consistent with both the EM and super-resolution data. We argue that synapses are composed of modules consisting of matrix material and potentially one nanocluster. LTP induction can add a trans-synaptic nanocluster to a module, thereby converting a silent module to an AMPA functional module. LTP can also add modules by a linear process, thereby producing an approximately 10-fold gradation in synapse size and strength.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'.
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Affiliation(s)
- Kang K L Liu
- Department of Physics, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Michael F Hagan
- Department of Physics, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - John E Lisman
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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98
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Lisman J. Glutamatergic synapses are structurally and biochemically complex because of multiple plasticity processes: long-term potentiation, long-term depression, short-term potentiation and scaling. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0260. [PMID: 28093558 DOI: 10.1098/rstb.2016.0260] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2016] [Indexed: 01/03/2023] Open
Abstract
Synapses are complex because they perform multiple functions, including at least six mechanistically different forms of plasticity. Here, I comment on recent developments regarding these processes. (i) Short-term potentiation (STP), a Hebbian process that requires small amounts of synaptic input, appears to make strong contributions to some forms of working memory. (ii) The rules for long-term potentiation (LTP) induction in CA3 have been clarified: induction does not depend obligatorily on backpropagating sodium spikes but, rather, on dendritic branch-specific N-methyl-d-aspartate (NMDA) spikes. (iii) Late LTP, a process that requires a dopamine signal (and is therefore neoHebbian), is mediated by trans-synaptic growth of the synapse, a growth that occurs about an hour after LTP induction. (iv) LTD processes are complex and include both homosynaptic and heterosynaptic forms. (v) Synaptic scaling produced by changes in activity levels are not primarily cell-autonomous, but rather depend on network activity. (vi) The evidence for distance-dependent scaling along the primary dendrite is firm, and a plausible structural-based mechanism is suggested.Ideas about the mechanisms of synaptic function need to take into consideration newly emerging data about synaptic structure. Recent super-resolution studies indicate that glutamatergic synapses are modular (module size 70-80 nm), as predicted by theoretical work. Modules are trans-synaptic structures and have high concentrations of postsynaptic density-95 (PSD-95) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. These modules function as quasi-independent loci of AMPA-mediated transmission and may be independently modifiable, suggesting a new understanding of quantal transmission.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity.'
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Affiliation(s)
- John Lisman
- Biology Department, Brandeis University, Waltham, MA, USA
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99
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Heller JP, Rusakov DA. The Nanoworld of the Tripartite Synapse: Insights from Super-Resolution Microscopy. Front Cell Neurosci 2017; 11:374. [PMID: 29225567 PMCID: PMC5705901 DOI: 10.3389/fncel.2017.00374] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/10/2017] [Indexed: 12/17/2022] Open
Abstract
Synaptic connections between individual nerve cells are fundamental to the process of information transfer and storage in the brain. Over the past decades a third key partner of the synaptic machinery has been unveiled: ultrathin processes of electrically passive astroglia which often surround pre- and postsynaptic structures. The recent advent of super-resolution (SR) microscopy has begun to uncover the dynamic nanoworld of synapses and their astroglial environment. Here we overview and discuss the current progress in our understanding of the synaptic nanoenvironment, as gleaned from the imaging methods that go beyond the diffraction limit of conventional light microscopy. We argue that such methods are essential to achieve a new level of comprehension pertinent to the principles of signal integration in the brain.
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Affiliation(s)
- Janosch P Heller
- UCL Institute of Neurology, University College London, London, United Kingdom
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, United Kingdom.,Institute of Neuroscience, University of Nizhny Novgorod, Nizhny Novgorod, Russia
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100
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Abstract
At each of the brain's vast number of synapses, the presynaptic nerve terminal, synaptic cleft, and postsynaptic specialization form a transcellular unit to enable efficient transmission of information between neurons. While we know much about the molecular machinery within each compartment, we are only beginning to understand how these compartments are structurally registered and functionally integrated with one another. This review will describe the organization of each compartment and then discuss their alignment across pre- and postsynaptic cells at a nanometer scale. We propose that this architecture may allow for precise synaptic information exchange and may be modulated to contribute to the remarkable plasticity of brain function.
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Affiliation(s)
- Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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