51
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Lovatt M, Leistner C, Frank RAW. Bridging length scales from molecules to the whole organism by cryoCLEM and cryoET. Faraday Discuss 2022; 240:114-126. [PMID: 35959706 PMCID: PMC9642002 DOI: 10.1039/d2fd00081d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/17/2022] [Indexed: 01/09/2023]
Abstract
Resolving atomic structures of isolated proteins has uncovered mechanisms and fundamental processes in biology. However, many functions can only be tested in the context of intact cells and tissues that are many orders of magnitude larger than the macromolecules on which they depend. Therefore, methods that interrogate macromolecular structure in situ provide a means of directly relating structure to function across length scales. Here, we developed several workflows using cryogenic correlated light and electron microscopy (cryoCLEM) and electron tomography (cryoET) that can bridge this gap to reveal the molecular infrastructure that underlies higher order functions within cells and tissues. We also describe experimental design considerations, including cryoCLEM labelling, sample preparation, and quality control, for determining the in situ molecular architectures within native, hydrated cells and tissues.
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Affiliation(s)
- Megan Lovatt
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
| | - Conny Leistner
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
| | - René A W Frank
- Astbury Centre of Structural Molecular Biology, School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT, UK.
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52
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Dissection of the long-range projections of specific neurons at the synaptic level in the whole mouse brain. Proc Natl Acad Sci U S A 2022; 119:e2202536119. [PMID: 36161898 PMCID: PMC9546530 DOI: 10.1073/pnas.2202536119] [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] [Indexed: 11/18/2022] Open
Abstract
Through synaptic connections, long-range circuits transmit information among neurons and connect different brain regions to form functional motifs and execute specific functions. Tracing the synaptic distribution of specific neurons requires submicron-level resolution information. However, it is a great challenge to map the synaptic terminals completely because these fine structures span multiple regions, even in the whole brain. Here, we develop a pipeline including viral tracing, sample embedding, fluorescent micro-optical sectional tomography, and big data processing. We mapped the whole-brain distribution and architecture of long projections of the parvalbumin neurons in the basal forebrain at the synaptic level. These neurons send massive projections to multiple downstream regions with subregional preference. With three-dimensional reconstruction in the targeted areas, we found that synaptic degeneration was inconsistent with the accumulation of amyloid-β plaques but was preferred in memory-related circuits, such as hippocampal formation and thalamus, but not in most hypothalamic nuclei in 8-month-old mice with five familial Alzheimer's disease mutations. Our pipeline provides a platform for generating a whole-brain atlas of cell-type-specific synaptic terminals in the physiological and pathological brain, which can provide an important resource for the study of the organizational logic of specific neural circuits and the circuitry changes in pathological conditions.
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53
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Sharma G, Banerjee S. Activity-regulated E3 ubiquitin ligase TRIM47 modulates excitatory synapse development. Front Mol Neurosci 2022; 15:943980. [PMID: 36211980 PMCID: PMC9532517 DOI: 10.3389/fnmol.2022.943980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
The Ubiquitin Proteasome System (UPS) has been shown to regulate neuronal development and synapse formation. Activity-dependent regulation of E3 ligase, a component of the UPS that targets specific proteins for proteasome-mediated degradation, is emerging as a pivotal player for the establishment of functional synapses. Here, we identified TRIM47 as a developmentally regulated E3 ligase that is expressed in rat hippocampus during the temporal window of synapse formation. We have demonstrated that the expression of TRIM47 is regulated by the glutamate-induced synaptic activity of hippocampal neurons in culture. In addition, the activity-dependent enhancement of TRIM47 expression is recapitulated following the object location test, a hippocampus-dependent spatial memory paradigm. We observed that this enhancement of TRIM47 expression requires NMDA receptor activation. The knockdown of TRIM47 leads to an enhancement of spine density without affecting dendritic complexity. Furthermore, we observed an increase in excitatory synapse development upon loss of TRIM47 function. Comprehensively, our study identified an activity-regulated E3 ligase that drives excitatory synapse formation in hippocampal neurons.
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54
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Zhang C, Shi G, Li G, Zuo K, Bai X, Meng Q, Huang M. Paraquat induces microglial cause early neuronal synaptic deficits through activation of the classical complement cascade response. Immunobiology 2022; 227:152275. [PMID: 36152426 DOI: 10.1016/j.imbio.2022.152275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/30/2022] [Accepted: 09/01/2022] [Indexed: 11/05/2022]
Abstract
Synapse loss is considered to be an early event in the dysfunction of the central nervous system (CNS), precedes neuronal decline, which is the main pathological change in mild cognitive impairment (MCI). Accumulating evidence has shown that neuronal synapse loss is associated with hyperactivity of microglial phagocytosis. In the CNS, microglia act as macrophages to clear cellular debris and weakened synapses, but the mechanism by which microglia activation leads to phagocytosis disorder remains unclear. Therefore, we treated mice with paraquat (PQ) in intraperitoneal injection to explore the mechanism by which microglia exert immunotoxicity in the CNS and cause neuronal synapse loss. Immunofluorescence results exposed synapses decreased with PQ exposure time, but the staining HE and Nissl showed that neuronal cell bodies were hardly affected. Fluorescence co-localization found that C1q (classical complement cascade initiation factor) was gradually deposited in the postsynaptic membrane of neurons to trigger the cascade reaction, thereby causing the excessive deposition of C3, a key factor of the classical complement cascade, and further induces hyperactivation of microglia, leads to phagocytosis disorder. IHC results demonstrated that the parallel relationship. Therefore, all our preliminary results throw light on the mechanism by which PQ abnormally triggers the immune system to produce immunotoxicity leading to microglial phagocytic dysfunction.
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Affiliation(s)
- Chunhui Zhang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Ge Shi
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Guoliang Li
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Kai Zuo
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Xinghua Bai
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Qi Meng
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China
| | - Min Huang
- School of Public Health and Management, Ningxia Medical University, Yinchuan, China; Key Laboratory of Environmental Factors and Chronic Disease Control, Yinchuan, China.
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55
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Sarkar D, Kang J, Wassie AT, Schroeder ME, Peng Z, Tarr TB, Tang AH, Niederst ED, Young JZ, Su H, Park D, Yin P, Tsai LH, Blanpied TA, Boyden ES. Revealing nanostructures in brain tissue via protein decrowding by iterative expansion microscopy. Nat Biomed Eng 2022; 6:1057-1073. [PMID: 36038771 PMCID: PMC9551354 DOI: 10.1038/s41551-022-00912-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 06/22/2022] [Indexed: 12/25/2022]
Abstract
Many crowded biomolecular structures in cells and tissues are inaccessible to labelling antibodies. To understand how proteins within these structures are arranged with nanoscale precision therefore requires that these structures be decrowded before labelling. Here we show that an iterative variant of expansion microscopy (the permeation of cells and tissues by a swellable hydrogel followed by isotropic hydrogel expansion, to allow for enhanced imaging resolution with ordinary microscopes) enables the imaging of nanostructures in expanded yet otherwise intact tissues at a resolution of about 20 nm. The method, which we named 'expansion revealing' and validated with DNA-probe-based super-resolution microscopy, involves gel-anchoring reagents and the embedding, expansion and re-embedding of the sample in homogeneous swellable hydrogels. Expansion revealing enabled us to use confocal microscopy to image the alignment of pre-synaptic calcium channels with post-synaptic scaffolding proteins in intact brain circuits, and to uncover periodic amyloid nanoclusters containing ion-channel proteins in brain tissue from a mouse model of Alzheimer's disease. Expansion revealing will enable the further discovery of previously unseen nanostructures within cells and tissues.
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Affiliation(s)
- Deblina Sarkar
- Media Lab, MIT, Cambridge, MA, 02139, USA.,MIT Center for Neurobiological Engineering, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Jinyoung Kang
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Asmamaw T Wassie
- Department of Biological Engineering, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Margaret E. Schroeder
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA
| | - Zhuyu Peng
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Tyler B. Tarr
- Department of Physiology, 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.,CAS Key Laboratory of Brain Function and Disease, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230031, China
| | - Emily D. Niederst
- The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Jennie, Z. Young
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Hanquan Su
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Demian Park
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Li-Huei Tsai
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA. .,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Correspondence and requests for materials should be addressed to Li-Huei Tsai, Thomas A. Blanpied or Edward S. Boyden. , ,
| | - Edward S. Boyden
- MIT Center for Neurobiological Engineering, MIT, Cambridge, MA, 02139, USA.,MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,Department of Biological Engineering, MIT, Cambridge, MA, 02139, USA.,Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,Koch Institute, MIT, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Cambridge, MA, 02139, USA.,Media Arts and Sciences, MIT, Cambridge, MA, 02139, USA.,K. Lisa Yang Center for Bionics, MIT, Cambridge, MA, 02139, USA.,Correspondence and requests for materials should be addressed to Li-Huei Tsai, Thomas A. Blanpied or Edward S. Boyden. , ,
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56
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Ventura-Antunes AL, Herculano-Houzel S. Energy supply per neuron is constrained by capillary density in the mouse brain. Front Integr Neurosci 2022; 16:760887. [PMID: 36105258 PMCID: PMC9465999 DOI: 10.3389/fnint.2022.760887] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 07/28/2022] [Indexed: 11/18/2022] Open
Abstract
Neuronal densities vary enormously across sites within a brain. Does the density of the capillary bed vary accompanying the presumably larger energy requirement of sites with more neurons, or with larger neurons, or is energy supply constrained by a mostly homogeneous capillary bed? Here we find evidence for the latter, with a capillary bed that represents typically between 0.7 and 1.5% of the volume of the parenchyma across various sites in the mouse brain, whereas neuronal densities vary by at least 100-fold. As a result, the ratio of capillary cells per neuron decreases uniformly with increasing neuronal density and therefore with smaller average neuronal size across sites. Thus, given the relatively constant capillary density compared to neuronal density in the brain, blood and energy availability per neuron is presumably dependent on how many neurons compete for the limited supply provided by a mostly homogeneous capillary bed. Additionally, we find that local capillary density is not correlated with local synapse densities, although there is a small but significant correlation between lower neuronal density (and therefore larger neuronal size) and more synapses per neuron within the restricted range of 6,500–9,500 across cortical sites. Further, local variations in the glial/neuron ratio are not correlated with local variations in the number of synapses per neuron or local synaptic densities. These findings suggest that it is not that larger neurons, neurons with more synapses, or even sites with more synapses demand more energy, but simply that larger neurons (in low density sites) have more energy available per cell and for the totality of its synapses than smaller neurons (in high density sites) due to competition for limited resources supplied by a capillary bed of fairly homogeneous density throughout the brain.
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Affiliation(s)
- aLissa Ventura-Antunes
- Instituto de Ciências Biomédicas, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Department of Psychology, Vanderbilt University, Nashville, TN, United States
- Department of Neurology, Vanderbilt Medical Center, Nashville, TN, United States
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN, United States
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
- *Correspondence: Suzana Herculano-Houzel,
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57
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Interrogating structural plasticity among synaptic engrams. Curr Opin Neurobiol 2022; 75:102552. [DOI: 10.1016/j.conb.2022.102552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 11/21/2022]
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58
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The evolution of synaptic and cognitive capacity: Insights from the nervous system transcriptome of Aplysia. Proc Natl Acad Sci U S A 2022; 119:e2122301119. [PMID: 35867761 PMCID: PMC9282427 DOI: 10.1073/pnas.2122301119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The gastropod mollusk Aplysia is an important model for cellular and molecular neurobiological studies, particularly for investigations of molecular mechanisms of learning and memory. We developed an optimized assembly pipeline to generate an improved Aplysia nervous system transcriptome. This improved transcriptome enabled us to explore the evolution of cognitive capacity at the molecular level. Were there evolutionary expansions of neuronal genes between this relatively simple gastropod Aplysia (20,000 neurons) and Octopus (500 million neurons), the invertebrate with the most elaborate neuronal circuitry and greatest behavioral complexity? Are the tremendous advances in cognitive power in vertebrates explained by expansion of the synaptic proteome that resulted from multiple rounds of whole genome duplication in this clade? Overall, the complement of genes linked to neuronal function is similar between Octopus and Aplysia. As expected, a number of synaptic scaffold proteins have more isoforms in humans than in Aplysia or Octopus. However, several scaffold families present in mollusks and other protostomes are absent in vertebrates, including the Fifes, Lev10s, SOLs, and a NETO family. Thus, whereas vertebrates have more scaffold isoforms from select families, invertebrates have additional scaffold protein families not found in vertebrates. This analysis provides insights into the evolution of the synaptic proteome. Both synaptic proteins and synaptic plasticity evolved gradually, yet the last deuterostome-protostome common ancestor already possessed an elaborate suite of genes associated with synaptic function, and critical for synaptic plasticity.
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59
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Stachowicz K. Is PSD-95 entangled in the side effects of antidepressants? Neurochem Int 2022; 159:105391. [PMID: 35817245 DOI: 10.1016/j.neuint.2022.105391] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 01/13/2023]
Abstract
PSD-95 is a component and a building block of an excitatory synapse. PSD-95 is a specialized protein that is part of a "combination lock" system responsible for plastic events at the synapse, such as receptor expression, which consequently induces changes in the PSD structure and thus affects synaptic plasticity. The possible involvement of PSD-95 in antidepressant side effects related to cognitive function and psychosis will be considered. An attempt will be made to trace the sequence of events in the proposed mechanism leading to these disorders, focusing mainly on NMDA receptors. Understanding the mechanisms of action of compounds with antidepressant potential may facilitate the design of safer drugs.
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Affiliation(s)
- Katarzyna Stachowicz
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna, 12, 31-343, Kraków, Poland.
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60
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Complex regulation of Gephyrin splicing is a determinant of inhibitory postsynaptic diversity. Nat Commun 2022; 13:3507. [PMID: 35717442 PMCID: PMC9206673 DOI: 10.1038/s41467-022-31264-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/10/2022] [Indexed: 01/05/2023] Open
Abstract
Gephyrin (GPHN) regulates the clustering of postsynaptic components at inhibitory synapses and is involved in pathophysiology of neuropsychiatric disorders. Here, we uncover an extensive diversity of GPHN transcripts that are tightly controlled by splicing during mouse and human brain development. Proteomic analysis reveals at least a hundred isoforms of GPHN incorporated at inhibitory Glycine and gamma-aminobutyric acid A receptors containing synapses. They exhibit different localization and postsynaptic clustering properties, and altering the expression level of one isoform is sufficient to affect the number, size, and density of inhibitory synapses in cerebellar Purkinje cells. Furthermore, we discovered that splicing defects reported in neuropsychiatric disorders are carried by multiple alternative GPHN transcripts, demonstrating the need for a thorough analysis of the GPHN transcriptome in patients. Overall, we show that alternative splicing of GPHN is an important genetic variation to consider in neurological diseases and a determinant of the diversity of postsynaptic inhibitory synapses. The protein gephyrin is involved in organizing synapses. Here, the authors show how different transcripts of gephyrin form and regulate inhibitory synapses.
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61
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Paget-Blanc V, Pfeffer ME, Pronot M, Lapios P, Angelo MF, Walle R, Cordelières FP, Levet F, Claverol S, Lacomme S, Petrel M, Martin C, Pitard V, De Smedt Peyrusse V, Biederer T, Perrais D, Trifilieff P, Herzog E. A synaptomic analysis reveals dopamine hub synapses in the mouse striatum. Nat Commun 2022; 13:3102. [PMID: 35660742 PMCID: PMC9166739 DOI: 10.1038/s41467-022-30776-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Dopamine transmission is involved in reward processing and motor control, and its impairment plays a central role in numerous neurological disorders. Despite its strong pathophysiological relevance, the molecular and structural organization of the dopaminergic synapse remains to be established. Here, we used targeted labelling and fluorescence activated sorting to purify striatal dopaminergic synaptosomes. We provide the proteome of dopaminergic synapses with 57 proteins specifically enriched. Beyond canonical markers of dopamine neurotransmission such as dopamine biosynthetic enzymes and cognate receptors, we validated 6 proteins not previously described as enriched. Moreover, our data reveal the adhesion of dopaminergic synapses to glutamatergic, GABAergic or cholinergic synapses in structures we named “dopamine hub synapses”. At glutamatergic synapses, pre- and postsynaptic markers are significantly increased upon association with dopamine synapses. Dopamine hub synapses may thus support local dopaminergic signalling, complementing volume transmission thought to be the major mechanism by which monoamines modulate network activity. The neurotransmitter dopamine is an important regulator of brain function. Here the authors describe “dopamine hub synapses”, where dopamine transmission may act in synergy with other neurotransmitters.
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Affiliation(s)
- Vincent Paget-Blanc
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Marlene E Pfeffer
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Marie Pronot
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Paul Lapios
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Maria-Florencia Angelo
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Roman Walle
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Fabrice P Cordelières
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, F-33000, Bordeaux, France
| | - Florian Levet
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.,Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, F-33000, Bordeaux, France
| | | | - Sabrina Lacomme
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, F-33000, Bordeaux, France
| | - Mélina Petrel
- Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, F-33000, Bordeaux, France
| | - Christelle Martin
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Vincent Pitard
- UB'FACSility CNRS UMS 3427, INSERM US 005, Univ. Bordeaux, F-33000, Bordeaux, France
| | | | - Thomas Biederer
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - David Perrais
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Pierre Trifilieff
- Univ. Bordeaux, INRAE, Bordeaux INP, NutriNeuro, UMR 1286, F-33000, Bordeaux, France
| | - Etienne Herzog
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.
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62
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González-Calvo I, Cizeron M, Bessereau JL, Selimi F. Synapse Formation and Function Across Species: Ancient Roles for CCP, CUB, and TSP-1 Structural Domains. Front Neurosci 2022; 16:866444. [PMID: 35546877 PMCID: PMC9083331 DOI: 10.3389/fnins.2022.866444] [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: 01/31/2022] [Accepted: 03/28/2022] [Indexed: 11/17/2022] Open
Abstract
The appearance of synapses was a crucial step in the creation of the variety of nervous systems that are found in the animal kingdom. With increased complexity of the organisms came a greater number of synaptic proteins. In this review we describe synaptic proteins that contain the structural domains CUB, CCP, or TSP-1. These domains are found in invertebrates and vertebrates, and CUB and CCP domains were initially described in proteins belonging to the complement system of innate immunity. Interestingly, they are found in synapses of the nematode C. elegans, which does not have a complement system, suggesting an ancient function. Comparison of the roles of CUB-, CCP-, and TSP-1 containing synaptic proteins in various species shows that in more complex nervous systems, these structural domains are combined with other domains and that there is partial conservation of their function. These three domains are thus basic building blocks of the synaptic architecture. Further studies of structural domains characteristic of synaptic proteins in invertebrates such as C. elegans and comparison of their role in mammals will help identify other conserved synaptic molecular building blocks. Furthermore, this type of functional comparison across species will also identify structural domains added during evolution in correlation with increased complexity, shedding light on mechanisms underlying cognition and brain diseases.
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Affiliation(s)
- Inés González-Calvo
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Mélissa Cizeron
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5284, INSERM U-1314, MeLiS, Institut NeuroMyoGène, Lyon, France
| | - Jean-Louis Bessereau
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5284, INSERM U-1314, MeLiS, Institut NeuroMyoGène, Lyon, France
| | - Fekrije Selimi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
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63
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Lim D, Kim D, Um JW, Ko J. Reassessing synaptic adhesion pathways. Trends Neurosci 2022; 45:517-528. [DOI: 10.1016/j.tins.2022.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 01/19/2023]
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64
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Mateus JC, Weaver S, van Swaay D, Renz AF, Hengsteler J, Aguiar P, Vörös J. Nanoscale Patterning of In Vitro Neuronal Circuits. ACS NANO 2022; 16:5731-5742. [PMID: 35404570 DOI: 10.1021/acsnano.1c10750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Methods for patterning neurons in vitro have gradually improved and are used to investigate questions that are difficult to address in or ex vivo. Though these techniques guide axons between groups of neurons, multiscale control of neuronal connectivity, from circuits to synapses, is yet to be achieved in vitro. As studying neuronal circuits with synaptic resolution in vivo poses significant challenges, we present an in vitro alternative to validate biophysical and computational models. In this work we use a combination of electron beam lithography and photolithography to create polydimethylsiloxane (PDMS) structures with features ranging from 150 nm to a few millimeters. Leveraging the difference between average axon and dendritic spine diameters, we restrict axon growth while allowing spines to pass through nanochannels to guide synapse formation between small groups of neurons (i.e., nodes). We show this technique can be used to generate large numbers of isolated feed-forward circuits where connections between nodes are restricted to regions connected by nanochannels. Using a genetically encoded calcium indicator in combination with fluorescently tagged postsynaptic protein, PSD-95, we demonstrate functional synapses can form in this region.
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Affiliation(s)
- José C Mateus
- Neuroengineering and Computational Neuroscience Laboratory, i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Sean Weaver
- Laboratory for Biosensors and Bioelectronics, ETH Zürich, 8092 Zürich, Switzerland
| | | | - Aline F Renz
- Laboratory for Biosensors and Bioelectronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Julian Hengsteler
- Laboratory for Biosensors and Bioelectronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Paulo Aguiar
- Neuroengineering and Computational Neuroscience Laboratory, i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - János Vörös
- Laboratory for Biosensors and Bioelectronics, ETH Zürich, 8092 Zürich, Switzerland
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65
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Broadhead MJ, Bonthron C, Waddington J, Smith WV, Lopez MF, Burley S, Valli J, Zhu F, Komiyama NH, Smith C, Grant SGN, Miles GB. Selective vulnerability of tripartite synapses in amyotrophic lateral sclerosis. Acta Neuropathol 2022; 143:471-486. [PMID: 35305541 PMCID: PMC8960590 DOI: 10.1007/s00401-022-02412-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder. Separate lines of evidence suggest that synapses and astrocytes play a role in the pathological mechanisms underlying ALS. Given that astrocytes make specialised contacts with some synapses, called tripartite synapses, we hypothesise that tripartite synapses could act as the fulcrum of disease in ALS. To test this hypothesis, we have performed an extensive microscopy-based investigation of synapses and tripartite synapses in the spinal cord of ALS model mice and post-mortem human tissue from ALS cases. We reveal widescale synaptic changes at the early symptomatic stages of the SOD1G93a mouse model. Super-resolution microscopy reveals that large complex postsynaptic structures are lost in ALS mice. Most surprisingly, tripartite synapses are selectively lost, while non-tripartite synapses remain in equal number to healthy controls. Finally, we also observe a similar selective loss of tripartite synapses in human post-mortem ALS spinal cords. From these data we conclude that tripartite synaptopathy is a key hallmark of ALS.
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66
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Park C, Gim J, Lee S, Lee KJ, Kim JS. Automated Synapse Detection Method for Cerebellar Connectomics. Front Neuroanat 2022; 16:760279. [PMID: 35360651 PMCID: PMC8963724 DOI: 10.3389/fnana.2022.760279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 02/14/2022] [Indexed: 11/17/2022] Open
Abstract
The connectomic analyses of large-scale volumetric electron microscope (EM) images enable the discovery of hidden neural connectivity. While the technologies for neuronal reconstruction of EM images are under rapid progress, the technologies for synapse detection are lagging behind. Here, we propose a method that automatically detects the synapses in the 3D EM images, specifically for the mouse cerebellar molecular layer (CML). The method aims to accurately detect the synapses between the reconstructed neuronal fragments whose types can be identified. It extracts the contacts between the reconstructed neuronal fragments and classifies them as synaptic or non-synaptic with the help of type information and two deep learning artificial intelligences (AIs). The method can also assign the pre- and postsynaptic sides of a synapse and determine excitatory and inhibitory synapse types. The accuracy of this method is estimated to be 0.955 in F1-score for a test volume of CML containing 508 synapses. To demonstrate the usability, we measured the size and number of the synapses in the volume and investigated the subcellular connectivity between the CML neuronal fragments. The basic idea of the method to exploit tissue-specific properties can be extended to other brain regions.
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Affiliation(s)
- Changjoo Park
- Department of Biological Sciences, Sungkyunkwan University, Suwon-si, South Korea
- Laboratory of Computational Neuroscience, Korea Brain Research Institute, Daegu, South Korea
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Jawon Gim
- Laboratory of Computational Neuroscience, Korea Brain Research Institute, Daegu, South Korea
- Laboratory of Synaptic Circuit Plasticity in Neural Circuits Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Sungjin Lee
- Department of Electrical Engineering and Computer Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Kea Joo Lee
- Laboratory of Synaptic Circuit Plasticity in Neural Circuits Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Jinseop S. Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon-si, South Korea
- Laboratory of Computational Neuroscience, Korea Brain Research Institute, Daegu, South Korea
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67
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Newmaster KT, Kronman FA, Wu YT, Kim Y. Seeing the Forest and Its Trees Together: Implementing 3D Light Microscopy Pipelines for Cell Type Mapping in the Mouse Brain. Front Neuroanat 2022; 15:787601. [PMID: 35095432 PMCID: PMC8794814 DOI: 10.3389/fnana.2021.787601] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/02/2021] [Indexed: 12/14/2022] Open
Abstract
The brain is composed of diverse neuronal and non-neuronal cell types with complex regional connectivity patterns that create the anatomical infrastructure underlying cognition. Remarkable advances in neuroscience techniques enable labeling and imaging of these individual cell types and their interactions throughout intact mammalian brains at a cellular resolution allowing neuroscientists to examine microscopic details in macroscopic brain circuits. Nevertheless, implementing these tools is fraught with many technical and analytical challenges with a need for high-level data analysis. Here we review key technical considerations for implementing a brain mapping pipeline using the mouse brain as a primary model system. Specifically, we provide practical details for choosing methods including cell type specific labeling, sample preparation (e.g., tissue clearing), microscopy modalities, image processing, and data analysis (e.g., image registration to standard atlases). We also highlight the need to develop better 3D atlases with standardized anatomical labels and nomenclature across species and developmental time points to extend the mapping to other species including humans and to facilitate data sharing, confederation, and integrative analysis. In summary, this review provides key elements and currently available resources to consider while developing and implementing high-resolution mapping methods.
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Affiliation(s)
- Kyra T Newmaster
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, United States
| | - Fae A Kronman
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, United States
| | - Yuan-Ting Wu
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, United States
| | - Yongsoo Kim
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, United States
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68
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Kv3 Channels Contribute to the Excitability of Subpopulations of Spinal Cord Neurons in Lamina VII. eNeuro 2022; 9:ENEURO.0510-21.2021. [PMID: 35058310 PMCID: PMC8868027 DOI: 10.1523/eneuro.0510-21.2021] [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: 12/13/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022] Open
Abstract
Autonomic parasympathetic preganglionic neurons (PGNs) drive contraction of the bladder during micturition but remain quiescent during bladder filling. This quiescence is postulated to be because of recurrent inhibition of PGN by fast-firing adjoining interneurons. Here, we defined four distinct neuronal types within Lamina VII, where PGN are situated, by combining whole cell patch clamp recordings with k-means clustering of a range of electrophysiological parameters. Additional morphologic analysis separated these neuronal classes into parasympathetic preganglionic populations (PGN) and a fast-firing interneuronal population. Kv3 channels are voltage-gated potassium channels (Kv) that allow fast and precise firing of neurons. We found that blockade of Kv3 channels by tetraethylammonium (TEA) reduced neuronal firing frequency and isolated high-voltage-activated Kv currents in the fast-firing population but had no effect in PGN populations. Furthermore, Kv3 blockade potentiated the local and descending inhibitory inputs to PGN indicating that Kv3-expressing inhibitory neurons are synaptically connected to PGN. Taken together, our data reveal that Kv3 channels are crucial for fast and regulated neuronal output of a defined population that may be involved in intrinsic spinal bladder circuits that underpin recurrent inhibition of PGN.
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69
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Gorka F, Daly S, Pearson CM, Bulovaite E, Zhang YP, Handa A, Grant SGN, Snaddon TN, Needham LM, Lee SF. A Comparative Study of High-Contrast Fluorescence Lifetime Probes for Imaging Amyloid in Tissue. J Phys Chem B 2021; 125:13710-13717. [PMID: 34883017 PMCID: PMC7615715 DOI: 10.1021/acs.jpcb.1c07762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Optical imaging of protein aggregates in living and post-mortem tissue can often be impeded by unwanted fluorescence, prompting the need for novel methods to extract meaningful signal in complex biological environments. Historically, benzothiazolium derivatives, prominently Thioflavin T, have been the state-of-the-art fluorescent probes for amyloid aggregates, but their optical, structural, and binding properties typically limit them to in vitro applications. This study compares the use of novel uncharged derivative, PAP_1, with parent Thioflavin T as a fluorescence lifetime imaging probe. This is applied specifically to imaging recombinant α-synuclein aggregates doped into brain tissue. Despite the 100-fold lower brightness of PAP_1 compared to that of Thioflavin T, PAP_1 binds to α-synuclein aggregates with an affinity several orders of magnitude greater than Thioflavin T; thus, we observe a specific decrease in the fluorescence lifetime of PAP_1 bound to α-synuclein aggregates, resulting in a separation of >1.4 standard deviations between PAP_1-stained brain tissue background and α-synuclein aggregates that is not observed with Thioflavin T. This enables contrast between highly fluorescent background tissue and amyloid fibrils that is attributed to the greater affinity of PAP_1 for α-synuclein aggregates, avoiding the substantial off-target staining observed with Thioflavin T.
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Affiliation(s)
- Felix Gorka
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Physics, Philipps-University Marburg, Marburg, 35032, Germany
| | - Sam Daly
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Colin M Pearson
- Department of Chemistry, Indiana University, Bloomington, Indiana, 47405, USA
| | - Edita Bulovaite
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Yu P. Zhang
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Anoushka Handa
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Seth G. N. Grant
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Thomas N. Snaddon
- Department of Chemistry, Indiana University, Bloomington, Indiana, 47405, USA
| | - Lisa-Maria Needham
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Steven F. Lee
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
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70
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Pronot M, Kieffer F, Gay AS, Debayle D, Forquet R, Poupon G, Schorova L, Martin S, Gwizdek C. Proteomic Identification of an Endogenous Synaptic SUMOylome in the Developing Rat Brain. Front Mol Neurosci 2021; 14:780535. [PMID: 34887727 PMCID: PMC8650717 DOI: 10.3389/fnmol.2021.780535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 10/26/2021] [Indexed: 12/16/2022] Open
Abstract
Synapses are highly specialized structures that interconnect neurons to form functional networks dedicated to neuronal communication. During brain development, synapses undergo activity-dependent rearrangements leading to both structural and functional changes. Many molecular processes are involved in this regulation, including post-translational modifications by the Small Ubiquitin-like MOdifier SUMO. To get a wider view of the panel of endogenous synaptic SUMO-modified proteins in the mammalian brain, we combined subcellular fractionation of rat brains at the post-natal day 14 with denaturing immunoprecipitation using SUMO2/3 antibodies and tandem mass spectrometry analysis. Our screening identified 803 candidate SUMO2/3 targets, which represents about 18% of the synaptic proteome. Our dataset includes neurotransmitter receptors, transporters, adhesion molecules, scaffolding proteins as well as vesicular trafficking and cytoskeleton-associated proteins, defining SUMO2/3 as a central regulator of the synaptic organization and function.
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Affiliation(s)
- Marie Pronot
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Félicie Kieffer
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Anne-Sophie Gay
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Delphine Debayle
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Raphaël Forquet
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Gwénola Poupon
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Lenka Schorova
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Stéphane Martin
- Institut National de la Santé Et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
| | - Carole Gwizdek
- Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Nice, France
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71
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Lautz JD, Tsegay KB, Zhu Z, Gniffke EP, Welsh JP, Smith SEP. Synaptic protein interaction networks encode experience by assuming stimulus-specific and brain-region-specific states. Cell Rep 2021; 37:110076. [PMID: 34852231 PMCID: PMC8722361 DOI: 10.1016/j.celrep.2021.110076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/01/2021] [Accepted: 11/09/2021] [Indexed: 11/02/2022] Open
Abstract
A core network of widely expressed proteins within the glutamatergic post-synapse mediates activity-dependent synaptic plasticity throughout the brain, but the specific proteomic composition of synapses differs between brain regions. Here, we address the question, how does proteomic composition affect activity-dependent protein-protein interaction networks (PINs) downstream of synaptic activity? Using quantitative multiplex co-immunoprecipitation, we compare the PIN response of in vivo or ex vivo neurons derived from different brain regions to activation by different agonists or different forms of eyeblink conditioning. We report that PINs discriminate between incoming stimuli using differential kinetics of overlapping and non-overlapping PIN parameters. Further, these "molecular logic rules" differ by brain region. We conclude that although the PIN of the glutamatergic post-synapse is expressed widely throughout the brain, its activity-dependent dynamics show remarkable stimulus-specific and brain-region-specific diversity. This diversity may help explain the challenges in developing molecule-specific drug therapies for neurological disorders.
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Affiliation(s)
- Jonathan D Lautz
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kaleb B Tsegay
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Zhiyi Zhu
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Edward P Gniffke
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - John P Welsh
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Stephen E P Smith
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA; Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA.
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72
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Park J, Khan S, Yun DH, Ku T, Villa KL, Lee JE, Zhang Q, Park J, Feng G, Nedivi E, Chung K. Epitope-preserving magnified analysis of proteome (eMAP). SCIENCE ADVANCES 2021; 7:eabf6589. [PMID: 34767453 PMCID: PMC8589305 DOI: 10.1126/sciadv.abf6589] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 09/24/2021] [Indexed: 05/28/2023]
Abstract
Synthetic tissue-hydrogel methods have enabled superresolution investigation of biological systems using diffraction-limited microscopy. However, chemical modification by fixatives can cause loss of antigenicity, limiting molecular interrogation of the tissue gel. Here, we present epitope-preserving magnified analysis of proteome (eMAP) that uses purely physical tissue-gel hybridization to minimize the loss of antigenicity while allowing permanent anchoring of biomolecules. We achieved success rates of 96% and 94% with synaptic antibodies for mouse and marmoset brains, respectively. Maximal preservation of antigenicity allows imaging of nanoscopic architectures in 1000-fold expanded tissues without additional signal amplification. eMAP-processed tissue gel can endure repeated staining and destaining without epitope loss or structural damage, enabling highly multiplexed proteomic analysis. We demonstrated the utility of eMAP as a nanoscopic proteomic interrogation tool by investigating molecular heterogeneity in inhibitory synapses in the mouse brain neocortex and characterizing the spatial distributions of synaptic proteins within synapses in mouse and marmoset brains.
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Affiliation(s)
- Joha Park
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
| | - Sarim Khan
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Department of Chemical Engineering, Indian Institute of Technology (IIT), Roorkee, Uttarakhand 247667, India
| | - Dae Hee Yun
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
| | - Taeyun Ku
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
| | - Katherine L. Villa
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
| | - Jiachen E. Lee
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
| | - Qiangge Zhang
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
- McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard University, Cambridge, MA 02142, USA
| | - Juhyuk Park
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Chemical Engineering, MIT, Cambridge, MA 02142, USA
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Guoping Feng
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
- McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard University, Cambridge, MA 02142, USA
| | - Elly Nedivi
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
| | - Kwanghun Chung
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
- Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA
- Department of Chemical Engineering, MIT, Cambridge, MA 02142, USA
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
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73
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Kjaergaard M, Petersen NC, Sørensen JB, Takeuchi T. Introducing the special issue on "Proteins and Circuits in Memory". Eur J Neurosci 2021; 54:6691-6695. [PMID: 34664317 DOI: 10.1111/ejn.15491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/10/2021] [Accepted: 10/11/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Magnus Kjaergaard
- Nordic EMBL Partnership for Molecular Medicine, The Danish Research Institute for Translational Neuroscience (DANDRITE), Aarhus, Denmark.,Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Copenhagen, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Nicolas Caesar Petersen
- Centre for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Tomonori Takeuchi
- Nordic EMBL Partnership for Molecular Medicine, The Danish Research Institute for Translational Neuroscience (DANDRITE), Aarhus, Denmark.,Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Copenhagen, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
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74
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Ban Y, Yu T, Feng B, Lorenz C, Wang X, Baker C, Zou Y. Prickle promotes the formation and maintenance of glutamatergic synapses by stabilizing the intercellular planar cell polarity complex. SCIENCE ADVANCES 2021; 7:eabh2974. [PMID: 34613779 PMCID: PMC8494439 DOI: 10.1126/sciadv.abh2974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/16/2021] [Indexed: 05/04/2023]
Abstract
Whether there exists a common signaling mechanism that assembles all glutamatergic synapses is unknown. We show here that knocking out Prickle1 and Prickle2 reduced the formation of the PSD-95–positive glutamatergic synapses in the hippocampus and medial prefrontal cortex in postnatal development by 70–80%. Prickle1 and Prickle2 double knockout in adulthood lead to the disassembly of 70 to 80% of the postsynaptic-density(PSD)-95–positive glutamatergic synapses. PSD-95–positive glutamatergic synapses in the hippocampus of Prickle2E8Q/E8Q mice were reduced by 50% at postnatal day 14. Prickle2 promotes synapse formation by antagonizing Vangl2 and stabilizing the intercellular complex of the planar cell polarity (PCP) components, whereas Prickle2 E8Q fails to do so. Coculture experiments show that the asymmetric PCP complexes can determine the presynaptic and postsynaptic polarity. In summary, the PCP components regulate the assembly and maintenance of a large number of glutamatergic synapses and specify the direction of synaptic transmission.
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Affiliation(s)
- Yue Ban
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ting Yu
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Bo Feng
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Charlotte Lorenz
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiaojia Wang
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Clayton Baker
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yimin Zou
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, CA 92093, USA
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75
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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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76
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Kuljis DA, Micheva KD, Ray A, Wegner W, Bowman R, Madison DV, Willig KI, Barth AL. Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons. Int J Mol Sci 2021; 22:ijms221810032. [PMID: 34576197 PMCID: PMC8467468 DOI: 10.3390/ijms221810032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 11/26/2022] Open
Abstract
Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABAARs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions.
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Affiliation(s)
- Dika A. Kuljis
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Kristina D. Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Ajit Ray
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Waja Wegner
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Ryan Bowman
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Daniel V. Madison
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Katrin I. Willig
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Alison L. Barth
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
- Correspondence: ; Tel.: +1-412-268-1198
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77
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A large-scale nanoscopy and biochemistry analysis of postsynaptic dendritic spines. Nat Neurosci 2021; 24:1151-1162. [PMID: 34168338 DOI: 10.1038/s41593-021-00874-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 05/13/2021] [Indexed: 02/05/2023]
Abstract
Dendritic spines, the postsynaptic compartments of excitatory neurotransmission, have different shapes classified from 'stubby' to 'mushroom-like'. Whereas mushroom spines are essential for adult brain function, stubby spines disappear during brain maturation. It is still unclear whether and how they differ in protein composition. To address this, we combined electron microscopy and quantitative biochemistry with super-resolution microscopy to annotate more than 47,000 spines for more than 100 synaptic targets. Surprisingly, mushroom and stubby spines have similar average protein copy numbers and topologies. However, an analysis of the correlation of each protein to the postsynaptic density mass, used as a marker of synaptic strength, showed substantially more significant results for the mushroom spines. Secretion and trafficking proteins correlated particularly poorly to the strength of stubby spines. This suggests that stubby spines are less likely to adequately respond to dynamic changes in synaptic transmission than mushroom spines, which possibly explains their loss during brain maturation.
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78
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Dai J, Patzke C, Liakath-Ali K, Seigneur E, Südhof TC. GluD1 is a signal transduction device disguised as an ionotropic receptor. Nature 2021; 595:261-265. [PMID: 34135511 DOI: 10.1038/s41586-021-03661-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 05/20/2021] [Indexed: 01/12/2023]
Abstract
Ionotropic glutamate delta receptors 1 (GluD1) and 2 (GluD2) exhibit the molecular architecture of postsynaptic ionotropic glutamate receptors, but assemble into trans-synaptic adhesion complexes by binding to secreted cerebellins that in turn interact with presynaptic neurexins1-4. It is unclear whether neurexin-cerebellin-GluD1/2 assemblies serve an adhesive synapse-formation function or mediate trans-synaptic signalling. Here we show in hippocampal synapses, that binding of presynaptic neurexin-cerebellin complexes to postsynaptic GluD1 controls glutamate receptor activity without affecting synapse numbers. Specifically, neurexin-1-cerebellin-2 and neurexin-3-cerebellin-2 complexes differentially regulate NMDA (N-methyl-D-aspartate) receptors and AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors by activating distinct postsynaptic GluD1 effector signals. Of note, minimal GluD1 and GluD2 constructs containing only their N-terminal cerebellin-binding and C-terminal cytoplasmic domains, joined by an unrelated transmembrane region, fully control the levels of NMDA and AMPA receptors. The distinct signalling specificity of presynaptic neurexin-1 and neurexin-35,6 is encoded by their alternatively spliced splice site 4 sequences, whereas the regulatory functions of postsynaptic GluD1 are mediated by conserved cytoplasmic sequence motifs spanning 5-13 residues. Thus, GluDs are signalling molecules that regulate NMDA and AMPA receptors by an unexpected transduction mechanism that bypasses their ionotropic receptor architecture and directly converts extracellular neurexin-cerebellin signals into postsynaptic receptor responses.
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Affiliation(s)
- Jinye Dai
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA. .,Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.
| | - Christopher Patzke
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.,Boler-Parseghian Center for Rare and Neglected Diseases, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Kif Liakath-Ali
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Erica Seigneur
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Thomas C Südhof
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA. .,Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.
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79
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Timonidis N, Tiesinga PHE. Progress towards a cellularly resolved mouse mesoconnectome is empowered by data fusion and new neuroanatomy techniques. Neurosci Biobehav Rev 2021; 128:569-591. [PMID: 34119523 DOI: 10.1016/j.neubiorev.2021.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/02/2021] [Accepted: 06/05/2021] [Indexed: 10/21/2022]
Abstract
Over the past decade there has been a rapid improvement in techniques for obtaining large-scale cellular level data related to the mouse brain connectome. However, a detailed mapping of cell-type-specific projection patterns is lacking, which would, for instance, allow us to study the role of circuit motifs in cognitive processes. In this work, we review advanced neuroanatomical and data fusion techniques within the context of a proposed Multimodal Connectomic Integration Framework for augmenting the cellularly resolved mouse mesoconnectome. First, we emphasize the importance of registering data modalities to a common reference atlas. We then review a number of novel experimental techniques that can provide data for characterizing cell-types in the mouse brain. Furthermore, we examine a number of data integration strategies, which involve fine-grained cell-type classification, spatial inference of cell densities, latent variable models for the mesoconnectome and multi-modal factorisation. Finally, we discuss a number of use cases which depend on connectome augmentation techniques, such as model simulations of functional connectivity and generating mechanistic hypotheses for animal disease models.
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Affiliation(s)
- Nestor Timonidis
- Neuroinformatics department, Donders Centre for Neuroscience, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Paul H E Tiesinga
- Neuroinformatics department, Donders Centre for Neuroscience, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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80
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Ramos-Vicente D, Grant SG, Bayés À. Metazoan evolution and diversity of glutamate receptors and their auxiliary subunits. Neuropharmacology 2021; 195:108640. [PMID: 34116111 DOI: 10.1016/j.neuropharm.2021.108640] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/27/2021] [Accepted: 06/01/2021] [Indexed: 01/18/2023]
Abstract
Glutamate is the major excitatory neurotransmitter in vertebrate and invertebrate nervous systems. Proteins involved in glutamatergic neurotransmission, and chiefly glutamate receptors and their auxiliary subunits, play key roles in nervous system function. Thus, understanding their evolution and uncovering their diversity is essential to comprehend how nervous systems evolved, shaping cognitive function. Comprehensive phylogenetic analysis of these proteins across metazoans have revealed that their evolution is much more complex than what can be anticipated from vertebrate genomes. This is particularly true for ionotropic glutamate receptors (iGluRs), as their current classification into 6 classes (AMPA, Kainate, Delta, NMDA1, NMDA2 and NMDA3) would be largely incomplete. New work proposes a classification of iGluRs into 4 subfamilies that encompass 10 classes. Vertebrate AMPA, Kainate and Delta receptors would belong to one of these subfamilies, named AKDF, the NMDA subunits would constitute another subfamily and non-vertebrate iGluRs would be organised into the previously unreported Epsilon and Lambda subfamilies. Similarly, the animal evolution of metabotropic glutamate receptors has resulted in the formation of four classes of these receptors, instead of the three currently recognised. Here we review our current knowledge on the animal evolution of glutamate receptors and their auxiliary subunits. This article is part of the special issue on 'Glutamate Receptors - Orphan iGluRs'.
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Affiliation(s)
- David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Seth Gn 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
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
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81
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Kay Y, Herring BE. An optogenetic method for investigating presynaptic molecular regulation. Sci Rep 2021; 11:11329. [PMID: 34059719 PMCID: PMC8166971 DOI: 10.1038/s41598-021-90244-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/07/2021] [Indexed: 12/11/2022] Open
Abstract
While efficient methods are well established for studying postsynaptic protein regulation of glutamatergic synapses in the mammalian central nervous system, similarly efficient methods are lacking for studying proteins regulating presynaptic function. In the present study, we introduce an optical/electrophysiological method for investigating presynaptic molecular regulation. Here, using an optogenetic approach, we selectively stimulate genetically modified presynaptic CA3 pyramidal neurons in the hippocampus and measure optically-induced excitatory postsynaptic currents produced in unmodified postsynaptic CA1 pyramidal neurons. While such use of optogenetics is not novel, previous implementation methods do not allow basic quantification of the changes in synaptic strength produced by genetic manipulations. We find that incorporating simultaneous recordings of fiber volley amplitude provides a control for optical stimulation intensity and, as a result, creates a metric of synaptic efficacy that can be compared across experimental conditions. In the present study, we utilize our new method to demonstrate that inhibition of synaptotagmin 1 expression in CA3 pyramidal neurons leads to a significant reduction in Schaffer collateral synapse function, an effect that is masked with conventional electrical stimulation. Our hope is that this method will expedite our understanding of molecular regulatory pathways that govern presynaptic function.
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Affiliation(s)
- Yuni Kay
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, 90089, USA
| | - Bruce E Herring
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, 90089, USA.
- Department of Biological Sciences, Neurobiology Section, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
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82
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Sahadevan S, Hembach KM, Tantardini E, Pérez-Berlanga M, Hruska-Plochan M, Megat S, Weber J, Schwarz P, Dupuis L, Robinson MD, De Rossi P, Polymenidou M. Synaptic FUS accumulation triggers early misregulation of synaptic RNAs in a mouse model of ALS. Nat Commun 2021; 12:3027. [PMID: 34021139 PMCID: PMC8140117 DOI: 10.1038/s41467-021-23188-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Mutations disrupting the nuclear localization of the RNA-binding protein FUS characterize a subset of amyotrophic lateral sclerosis patients (ALS-FUS). FUS regulates nuclear RNAs, but its role at the synapse is poorly understood. Using super-resolution imaging we determined that the localization of FUS within synapses occurs predominantly near the vesicle reserve pool of presynaptic sites. Using CLIP-seq on synaptoneurosomes, we identified synaptic FUS RNA targets, encoding proteins associated with synapse organization and plasticity. Significant increase of synaptic FUS during early disease in a mouse model of ALS was accompanied by alterations in density and size of GABAergic synapses. mRNAs abnormally accumulated at the synapses of 6-month-old ALS-FUS mice were enriched for FUS targets and correlated with those depicting increased short-term mRNA stability via binding primarily on multiple exonic sites. Our study indicates that synaptic FUS accumulation in early disease leads to synaptic impairment, potentially representing an initial trigger of neurodegeneration.
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Affiliation(s)
- Sonu Sahadevan
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Katharina M Hembach
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
- Department of Molecular Life Sciences and SIB Swiss Institute of Bioinformatics, University of Zurich, Zürich, Switzerland
| | - Elena Tantardini
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | | | | | - Salim Megat
- Inserm, University of Strasbourg, Strasbourg, France
| | - Julien Weber
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Petra Schwarz
- Institute of Neuropathology, University Hospital Zurich, Zürich, Switzerland
| | - Luc Dupuis
- Inserm, University of Strasbourg, Strasbourg, France
| | - Mark D Robinson
- Department of Molecular Life Sciences and SIB Swiss Institute of Bioinformatics, University of Zurich, Zürich, Switzerland
| | - Pierre De Rossi
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
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83
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van Gelder CAGH, Altelaar M. Neuroproteomics of the Synapse: Subcellular Quantification of Protein Networks and Signaling Dynamics. Mol Cell Proteomics 2021; 20:100087. [PMID: 33933679 PMCID: PMC8167277 DOI: 10.1016/j.mcpro.2021.100087] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 01/21/2023] Open
Abstract
One of the most fascinating features of the brain is its ability to adapt to its surroundings. Synaptic plasticity, the dynamic mechanism of functional and structural alterations in synaptic strength, is essential for brain functioning and underlies a variety of processes such as learning and memory. Although the molecular mechanisms underlying such rapid plasticity are not fully understood, a consensus exists on the important role of proteins. The study of these neuronal proteins using neuroproteomics has increased rapidly in the last decades, and advancements in MS-based proteomics have broadened our understanding of neuroplasticity exponentially. In this review, we discuss the trends in MS-based neuroproteomics for the study of synaptic protein-protein interactions and protein signaling dynamics, with a focus on sample types, different labeling and enrichment approaches, and data analysis and interpretation. We highlight studies from the last 5 years, with a focus on synapse structure, composition, functioning, or signaling and finally discuss some recent developments that could further advance the field of neuroproteomics.
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Affiliation(s)
- Charlotte A G H van Gelder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Netherlands Proteomics Center, Utrecht, The Netherlands.
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84
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Proietti Onori M, van Woerden GM. Role of calcium/calmodulin-dependent kinase 2 in neurodevelopmental disorders. Brain Res Bull 2021; 171:209-220. [PMID: 33774142 DOI: 10.1016/j.brainresbull.2021.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/28/2023]
Abstract
Neurodevelopmental disorders are a complex and heterogeneous group of neurological disorders characterized by their early-onset and estimated to affect more than 3% of children worldwide. The rapid advancement of sequencing technologies in the past years allowed the identification of hundreds of variants in several different genes causing neurodevelopmental disorders. Between those, new variants in the Calcium/calmodulin dependent protein kinase II (CAMK2) genes were recently linked to intellectual disability. Despite many years of research on CAMK2, this proves for the first time that this well-known and highly conserved molecule plays an important role in the human brain. In this review, we give an overview of the identified CAMK2 variants, and we speculate on potential mechanisms through which dysfunctions in CAMK2 result in neurodevelopmental disorders. Additionally, we discuss how the identification of CAMK2 variants might result in new exciting discoveries regarding the function of CAMK2 in the human brain.
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Affiliation(s)
- Martina Proietti Onori
- Department of Neuroscience, Erasmus MC, Rotterdam, 3015 GD, the Netherlands; The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, 3015 GD, the Netherlands
| | - Geeske M van Woerden
- Department of Neuroscience, Erasmus MC, Rotterdam, 3015 GD, the Netherlands; The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, 3015 GD, the Netherlands.
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85
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Uncovering Statistical Links Between Gene Expression and Structural Connectivity Patterns in the Mouse Brain. Neuroinformatics 2021; 19:649-667. [PMID: 33704701 PMCID: PMC8566442 DOI: 10.1007/s12021-021-09511-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2021] [Indexed: 11/16/2022]
Abstract
Finding links between genes and structural connectivity is of the utmost importance for unravelling the underlying mechanism of the brain connectome. In this study we identify links between the gene expression and the axonal projection density in the mouse brain, by applying a modified version of the Linked ICA method to volumetric data from the Allen Institute for Brain Science for identifying independent sources of information that link both modalities at the voxel level. We performed separate analyses on sets of projections from the visual cortex, the caudoputamen and the midbrain reticular nucleus, and we determined those brain areas, injections and genes that were most involved in independent components that link both gene expression and projection density data, while we validated their biological context through enrichment analysis. We identified representative and literature-validated cortico-midbrain and cortico-striatal projections, whose gene subsets were enriched with annotations for neuronal and synaptic function and related developmental and metabolic processes. The results were highly reproducible when including all available projections, as well as consistent with factorisations obtained using the Dictionary Learning and Sparse Coding technique. Hence, Linked ICA yielded reproducible independent components that were preserved under increasing data variance. Taken together, we have developed and validated a novel paradigm for linking gene expression and structural projection patterns in the mouse mesoconnectome, which can power future studies aiming to relate genes to brain function.
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86
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Zoupi L, Booker SA, Eigel D, Werner C, Kind PC, Spires-Jones TL, Newland B, Williams AC. Selective vulnerability of inhibitory networks in multiple sclerosis. Acta Neuropathol 2021; 141:415-429. [PMID: 33449171 PMCID: PMC7882577 DOI: 10.1007/s00401-020-02258-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 01/01/2023]
Abstract
In multiple sclerosis (MS), a chronic demyelinating disease of the central nervous system, neurodegeneration is detected early in the disease course and is associated with the long-term disability of patients. Neurodegeneration is linked to both inflammation and demyelination, but its exact cause remains unknown. This gap in knowledge contributes to the current lack of treatments for the neurodegenerative phase of MS. Here we ask if neurodegeneration in MS affects specific neuronal components and if it is the result of demyelination. Neuropathological examination of secondary progressive MS motor cortices revealed a selective vulnerability of inhibitory interneurons in MS. The generation of a rodent model of focal subpial cortical demyelination reproduces this selective neurodegeneration providing a new preclinical model for the study of neuroprotective treatments.
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Affiliation(s)
- Lida Zoupi
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Dimitri Eigel
- Leibniz-Institut Für Polymerforschung Dresden E.V, Max Bergmann Center of Biomaterials Dresden, Hohe Straße 6, 01069, Dresden, Germany
| | - Carsten Werner
- Leibniz-Institut Für Polymerforschung Dresden E.V, Max Bergmann Center of Biomaterials Dresden, Hohe Straße 6, 01069, Dresden, Germany
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- UK Dementia Research Institute, University of Edinburgh, Edinburgh, EH8 9JZ, UK
| | - Ben Newland
- Leibniz-Institut Für Polymerforschung Dresden E.V, Max Bergmann Center of Biomaterials Dresden, Hohe Straße 6, 01069, Dresden, Germany
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - Anna C Williams
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, EH16 4UU, UK.
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87
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Xu Y, Song X, Wang D, Wang Y, Li P, Li J. Proteomic insights into synaptic signaling in the brain: the past, present and future. Mol Brain 2021; 14:37. [PMID: 33596935 PMCID: PMC7888154 DOI: 10.1186/s13041-021-00750-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/09/2021] [Indexed: 12/29/2022] Open
Abstract
Chemical synapses in the brain connect neurons to form neural circuits, providing the structural and functional bases for neural communication. Disrupted synaptic signaling is closely related to a variety of neurological and psychiatric disorders. In the past two decades, proteomics has blossomed as a versatile tool in biological and biomedical research, rendering a wealth of information toward decoding the molecular machinery of life. There is enormous interest in employing proteomic approaches for the study of synapses, and substantial progress has been made. Here, we review the findings of proteomic studies of chemical synapses in the brain, with special attention paid to the key players in synaptic signaling, i.e., the synaptic protein complexes and their post-translational modifications. Looking toward the future, we discuss the technological advances in proteomics such as data-independent acquisition mass spectrometry (DIA-MS), cross-linking in combination with mass spectrometry (CXMS), and proximity proteomics, along with their potential to untangle the mystery of how the brain functions at the molecular level. Last but not least, we introduce the newly developed synaptomic methods. These methods and their successful applications marked the beginnings of the synaptomics era.
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Affiliation(s)
- Yalan Xu
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Xiuyue Song
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Dong Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China
| | - Jing Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Medical College, Qingdao University, Qingdao, 266021, China.
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88
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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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89
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Molecular Diversity of Glutamatergic and GABAergic Synapses from Multiplexed Fluorescence Imaging. eNeuro 2021; 8:ENEURO.0286-20.2020. [PMID: 33355295 PMCID: PMC7877457 DOI: 10.1523/eneuro.0286-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 11/25/2020] [Accepted: 12/07/2020] [Indexed: 01/01/2023] Open
Abstract
Neuronal synapses contain hundreds of different protein species important for regulating signal transmission. Characterizing differential expression profiles of proteins within synapses in distinct regions of the brain has revealed a high degree of synaptic diversity defined by unique molecular organization. Multiplexed imaging of in vitro rat primary hippocampal culture models at single synapse resolution offers new opportunities for exploring synaptic reorganization in response to chemical and genetic perturbations. Here, we combine 12-color multiplexed fluorescence imaging with quantitative image analysis and machine learning to identify novel synaptic subtypes within excitatory and inhibitory synapses based on the expression profiles of major synaptic components. We characterize differences in the correlated expression of proteins within these subtypes and we examine how the distribution of these synapses is modified following induction of synaptic plasticity. Under chronic suppression of neuronal activity, phenotypic characterization revealed coordinated increases in both excitatory and inhibitory protein levels without changes in the distribution of synaptic subtypes, suggesting concerted events targeting glutamatergic and GABAergic synapses. Our results offer molecular insight into the mechanisms of synaptic plasticity.
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90
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Kim HY, Um JW, Ko J. Proper synaptic adhesion signaling in the control of neural circuit architecture and brain function. Prog Neurobiol 2021; 200:101983. [PMID: 33422662 DOI: 10.1016/j.pneurobio.2020.101983] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Trans-synaptic cell-adhesion molecules are critical for governing various stages of synapse development and specifying neural circuit properties via the formation of multifarious signaling pathways. Recent studies have pinpointed the putative roles of trans-synaptic cell-adhesion molecules in mediating various cognitive functions. Here, we review the literature on the roles of a diverse group of central synaptic organizers, including neurexins (Nrxns), leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs), and their associated binding proteins, in regulating properties of specific type of synapses and neural circuits. In addition, we highlight the findings that aberrant synaptic adhesion signaling leads to alterations in the structures, transmission, and plasticity of specific synapses across diverse brain areas. These results seem to suggest that proper trans-synaptic signaling pathways by Nrxns, LAR-RPTPs, and their interacting network is likely to constitute central molecular complexes that form the basis for cognitive functions, and that these complexes are heterogeneously and complexly disrupted in many neuropsychiatric and neurodevelopmental disorders.
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Affiliation(s)
- Hee Young Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea; Core Protein Resources Center, DGIST, Daegu, 42988, South Korea.
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea.
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91
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Horner AE, Norris RH, McLaren-Jones R, Alexander L, Komiyama NH, Grant SGN, Nithianantharajah J, Kopanitsa MV. Learning and reaction times in mouse touchscreen tests are differentially impacted by mutations in genes encoding postsynaptic interacting proteins SYNGAP1, NLGN3, DLGAP1, DLGAP2 and SHANK2. GENES, BRAIN, AND BEHAVIOR 2021; 20:e12723. [PMID: 33347690 PMCID: PMC7615670 DOI: 10.1111/gbb.12723] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022]
Abstract
The postsynaptic terminal of vertebrate excitatory synapses contains a highly conserved multiprotein complex that comprises neurotransmitter receptors, cell-adhesion molecules, scaffold proteins and enzymes, which are essential for brain signalling and plasticity underlying behaviour. Increasingly, mutations in genes that encode postsynaptic proteins belonging to the PSD-95 protein complex, continue to be identified in neurodevelopmental disorders (NDDs) such as autism spectrum disorder, intellectual disability and epilepsy. These disorders are highly heterogeneous, sharing genetic aetiology and comorbid cognitive and behavioural symptoms. Here, by using genetically engineered mice and innovative touchscreen-based cognitive testing, we sought to investigate whether loss-of-function mutations in genes encoding key interactors of the PSD-95 protein complex display shared phenotypes in associative learning, updating of learned associations and reaction times. Our genetic dissection of mice with loss-of-function mutations in Syngap1, Nlgn3, Dlgap1, Dlgap2 and Shank2 showed that distinct components of the PSD-95 protein complex differentially regulate learning, cognitive flexibility and reaction times in cognitive processing. These data provide insights for understanding how human mutations in these genes lead to the manifestation of diverse and complex phenotypes in NDDs.
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Affiliation(s)
| | - Rebecca H Norris
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | | | | | - Noboru H Komiyama
- Genes to Cognition Programme, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery 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
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Jess Nithianantharajah
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Maksym V Kopanitsa
- Synome Ltd, Babraham Research Campus, Cambridge, UK
- UK Dementia Research Institute and Department of Brain Sciences, Imperial College, London, UK
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92
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Graves AR, Roth RH, Tan HL, Zhu Q, Bygrave AM, Lopez-Ortega E, Hong I, Spiegel AC, Johnson RC, Vogelstein JT, Tward DJ, Miller MI, Huganir RL. Visualizing synaptic plasticity in vivo by large-scale imaging of endogenous AMPA receptors. eLife 2021; 10:66809. [PMID: 34658338 PMCID: PMC8616579 DOI: 10.7554/elife.66809] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 10/16/2021] [Indexed: 02/06/2023] Open
Abstract
Elucidating how synaptic molecules such as AMPA receptors mediate neuronal communication and tracking their dynamic expression during behavior is crucial to understand cognition and disease, but current technological barriers preclude large-scale exploration of molecular dynamics in vivo. We have developed a suite of innovative methodologies that break through these barriers: a new knockin mouse line with fluorescently tagged endogenous AMPA receptors, two-photon imaging of hundreds of thousands of labeled synapses in behaving mice, and computer vision-based automatic synapse detection. Using these tools, we can longitudinally track how the strength of populations of synapses changes during behavior. We used this approach to generate an unprecedentedly detailed spatiotemporal map of synapses undergoing changes in strength following sensory experience. More generally, these tools can be used as an optical probe capable of measuring functional synapse strength across entire brain areas during any behavioral paradigm, describing complex system-wide changes with molecular precision.
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Affiliation(s)
- Austin R Graves
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
| | - Richard H Roth
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Han L Tan
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Qianwen Zhu
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Alexei M Bygrave
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Elena Lopez-Ortega
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ingie Hong
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Alina C Spiegel
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
| | - Richard C Johnson
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Joshua T Vogelstein
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel J Tward
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Michael I Miller
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Richard L Huganir
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
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93
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Unlocking the brain: A new method for Western blot protein detection from fixed brain tissue. J Neurosci Methods 2020; 348:108995. [PMID: 33202258 DOI: 10.1016/j.jneumeth.2020.108995] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/27/2020] [Accepted: 11/01/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Aldehyde fixation is a common process used to preserve the complex structure of biological samples ex vivo. This method of fixation relies on the formation of covalent bonds between aldehydes and amines present in the biomolecules of the sample. Aldehyde fixation is routinely performed in histological studies, however fixed tissue samples are rarely used for non-histological purposes as the fixation process is thought to make brain tissue unsuitable for traditional proteomic analyses such as Western blot. Advances in antigen-retrieval procedures have allowed detectable levels of protein to be solubilized from formaldehyde fixed tissue, opening the door for aldehyde-fixed samples to be used in both histological and proteomic approaches. NEW METHOD Here, we developed a series of antigen-retrieval steps for use on fixed-brain lysates to make them suitable for analysis by Western blot. RESULTS Prolonged exposure of the tissue homogenate to high temperature (90 °C for 2 h) in the presence of a concentrated formaldehyde scavenger and ionic detergent was sufficient to reveal a variety of synaptic and non-synaptic proteins on membrane blots. CONCLUSION This protocol has significant utility for future studies using fixed tissue samples in a variety of neuropathological conditions.
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94
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Ramos-Vicente D, Bayés À. AMPA receptor auxiliary subunits emerged during early vertebrate evolution by neo/subfunctionalization of unrelated proteins. Open Biol 2020; 10:200234. [PMID: 33108974 PMCID: PMC7653359 DOI: 10.1098/rsob.200234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In mammalian synapses, the function of ionotropic glutamate receptors is critically modulated by auxiliary subunits. Most of these specifically regulate the synaptic localization and electrophysiological properties of AMPA-type glutamate receptors (AMPARs). Here, we comprehensively investigated the animal evolution of the protein families that contain AMPAR auxiliary subunits (ARASs). We observed that, on average, vertebrates have four times more ARASs than other animal species. We also demonstrated that ARASs belong to four unrelated protein families: CACNG-GSG1, cornichon, shisa and Dispanin C. Our study demonstrates that, despite the ancient origin of these four protein families, the majority of ARASs emerged during vertebrate evolution by independent but convergent processes of neo/subfunctionalization that resulted in the multiple ARASs found in present vertebrate genomes. Importantly, although AMPARs appeared and diversified in the ancestor of bilateral animals, the ARAS expansion did not occur until much later, in early vertebrate evolution. We propose that the surge in ARASs and consequent increase in AMPAR functionalities, contributed to the increased complexity of vertebrate brains and cognitive functions.
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Affiliation(s)
- David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain.,Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain.,Universitat Autònoma de Barcelona, Barcelona, Spain
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95
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Synapse type-specific proteomic dissection identifies IgSF8 as a hippocampal CA3 microcircuit organizer. Nat Commun 2020; 11:5171. [PMID: 33057002 PMCID: PMC7560607 DOI: 10.1038/s41467-020-18956-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 09/23/2020] [Indexed: 12/20/2022] Open
Abstract
Excitatory and inhibitory neurons are connected into microcircuits that generate circuit output. Central in the hippocampal CA3 microcircuit is the mossy fiber (MF) synapse, which provides powerful direct excitatory input and indirect feedforward inhibition to CA3 pyramidal neurons. Here, we dissect its cell-surface protein (CSP) composition to discover novel regulators of MF synaptic connectivity. Proteomic profiling of isolated MF synaptosomes uncovers a rich CSP composition, including many CSPs without synaptic function and several that are uncharacterized. Cell-surface interactome screening identifies IgSF8 as a neuronal receptor enriched in the MF pathway. Presynaptic Igsf8 deletion impairs MF synaptic architecture and robustly decreases the density of bouton filopodia that provide feedforward inhibition. Consequently, IgSF8 loss impairs excitation/inhibition balance and increases excitability of CA3 pyramidal neurons. Our results provide insight into the CSP landscape and interactome of a specific excitatory synapse and reveal IgSF8 as a critical regulator of CA3 microcircuit connectivity and function. Mossy fiber synapses are key in CA3 microcircuit function. Here, the authors profile the mossy fiber synapse proteome and cell-surface interactome. They uncover a diverse repertoire of cell-surface proteins and identify the receptor IgSF8 as a regulator of CA3 microcircuit connectivity and function.
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96
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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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97
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Zhao X, van Praag H. Steps towards standardized quantification of adult neurogenesis. Nat Commun 2020; 11:4275. [PMID: 32848155 PMCID: PMC7450090 DOI: 10.1038/s41467-020-18046-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 08/03/2020] [Indexed: 02/07/2023] Open
Abstract
New neurons are generated in adult mammals. Adult hippocampal neurogenesis is considered to play an important role in cognition and mental health. The number and properties of newly born neurons are regulatable by a broad range of physiological and pathological conditions. To begin to understand the underlying cellular mechanisms and functional relevance of adult neurogenesis, many studies rely on quantification of adult-born neurons. However, lack of standardized methods to quantify new neurons is impeding research reproducibility across laboratories. Here, we review the importance of stereology, and propose why and how it should be applied to the study of adult neurogenesis.
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Affiliation(s)
- Xinyu Zhao
- Waisman Center and University of Wisconsin-Madison, Madison, WI, 53705, USA.
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Henriette van Praag
- Brain Institute and Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, 33458, USA.
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98
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Santuy A, Tomás-Roca L, Rodríguez JR, González-Soriano J, Zhu F, Qiu Z, Grant SGN, DeFelipe J, Merchan-Perez A. Estimation of the number of synapses in the hippocampus and brain-wide by volume electron microscopy and genetic labeling. Sci Rep 2020; 10:14014. [PMID: 32814795 PMCID: PMC7438319 DOI: 10.1038/s41598-020-70859-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/27/2020] [Indexed: 11/29/2022] Open
Abstract
Determining the number of synapses that are present in different brain regions is crucial to understand brain connectivity as a whole. Membrane-associated guanylate kinases (MAGUKs) are a family of scaffolding proteins that are expressed in excitatory glutamatergic synapses. We used genetic labeling of two of these proteins (PSD95 and SAP102), and Spinning Disc confocal Microscopy (SDM), to estimate the number of fluorescent puncta in the CA1 area of the hippocampus. We also used FIB-SEM, a three-dimensional electron microscopy technique, to calculate the actual numbers of synapses in the same area. We then estimated the ratio between the three-dimensional densities obtained with FIB-SEM (synapses/µm3) and the bi-dimensional densities obtained with SDM (puncta/100 µm2). Given that it is impractical to use FIB-SEM brain-wide, we used previously available SDM data from other brain regions and we applied this ratio as a conversion factor to estimate the minimum density of synapses in those regions. We found the highest densities of synapses in the isocortex, olfactory areas, hippocampal formation and cortical subplate. Low densities were found in the pallidum, hypothalamus, brainstem and cerebellum. Finally, the striatum and thalamus showed a wide range of synapse densities.
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Affiliation(s)
- Andrea Santuy
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223, Pozuelo de Alarcón, Madrid, Spain
| | - Laura Tomás-Roca
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223, Pozuelo de Alarcón, Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce, 37, 28002, Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED) ISCIII, Madrid, Spain
| | - Juncal González-Soriano
- Departamento de Anatomía y Embriología, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Fei Zhu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH16 4SB, UK.,UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Zhen Qiu
- 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
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223, Pozuelo de Alarcón, Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce, 37, 28002, Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED) ISCIII, Madrid, Spain
| | - Angel Merchan-Perez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223, Pozuelo de Alarcón, Madrid, Spain. .,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED) ISCIII, Madrid, Spain. .,Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, 28223, Pozuelo de Alarcón, Madrid, Spain.
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99
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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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100
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Trompoukis G, Rigas P, Leontiadis LJ, Papatheodoropoulos C. I h, GIRK, and KCNQ/Kv7 channels differently modulate sharp wave - ripples in the dorsal and ventral hippocampus. Mol Cell Neurosci 2020; 107:103531. [PMID: 32711112 DOI: 10.1016/j.mcn.2020.103531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/11/2020] [Accepted: 07/16/2020] [Indexed: 12/14/2022] Open
Abstract
Sharp waves and ripples (SPW-Rs) are endogenous transient patterns of hippocampus local network activity implicated in several functions including memory consolidation, and they are diversified between the dorsal and the ventral hippocampus. Ion channels in the neuronal membrane play important roles in cell and local network function. In this study, using transverse slices and field potential recordings from the CA1 field of rat hippocampus we show that GIRK and KCNQ2/3 potassium channels play a higher role in modulating SPW-Rs in the dorsal hippocampus, while Ih and other KCNQ (presumably KCNQ5) channels, contribute to shaping SPW-R activity more in the ventral than in dorsal hippocampus. Specifically, blockade of Ih channels by ZD 7288 reduced the rate of occurrence of SPW-Rs and increased the generation of SPW-Rs in the form of clusters in both hippocampal segments, while enhanced the amplitude of SPW-Rs only in the ventral hippocampus. Most effects of ZD 7288 appeared to be independent of NMDA receptors' activity. However, the effects of blockade of NMDA receptors depended on the functional state of Ih channels in both hippocampal segments. Blockade of GIRK channels by Tertiapin-Q increased the rate of occurrence of SPW-Rs only in the dorsal hippocampus and the probability of clusters in both segments of the hippocampus. Blockade of KCNQ2/3 channels by XE 991 increased the rate of occurrence of SPW-Rs and the probability of clusters in the dorsal hippocampus, and only reduced the clustered generation of SPW-Rs in the ventral hippocampus. The blocker of KCNQ1/2 channels, that also enhances KCNQ5 channels, UCL 2077, increased the probability of clusters and the power of the ripple oscillation in the ventral hippocampus only. These results suggest that GIRK, KCNQ and Ih channels represent a key mechanism for modulation of SPW-R activity which act differently in the dorsal and ventral hippocampus, fundamentally supporting functional diversification along the dorsal-ventral axis of the hippocampus.
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Affiliation(s)
- George Trompoukis
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
| | - Pavlos Rigas
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
| | - Leonidas J Leontiadis
- Laboratory of Physiology, Department of Medicine, University of Patras, Rion, Greece
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