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Cole AA, Reese TS. Transsynaptic Assemblies Link Domains of Presynaptic and Postsynaptic Intracellular Structures across the Synaptic Cleft. J Neurosci 2023; 43:5883-5892. [PMID: 37369583 PMCID: PMC10436760 DOI: 10.1523/jneurosci.2195-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
The chemical synapse is a complex machine separated into three parts: presynaptic, postsynaptic, and cleft. Super-resolution light microscopy has revealed alignment of presynaptic vesicle release machinery and postsynaptic neurotransmitter-receptors and scaffolding components in synapse spanning nanocolumns. Cryo-electron tomography confirmed that postsynaptic glutamate receptor-like structures align with presynaptic structures in proximity to synaptic vesicles into transsynaptic assemblies. In our electron tomographic renderings, nearly all transcleft structures visibly connect to intracellular structures through transmembrane structures to form transsynaptic assemblies, potentially providing a structural basis for transsynaptic alignment. Here, we describe the patterns of composition, distribution, and interactions of all assemblies spanning the synapse by producing three-dimensional renderings of all visibly connected structures in excitatory and inhibitory synapses in dissociated rat hippocampal neuronal cultures of both sexes prepared by high-pressure freezing and freeze-substitution. The majority of transcleft structures connect to material in both presynaptic and postsynaptic compartments. We found several instances of assemblies connecting to both synaptic vesicles and postsynaptic density scaffolding. Each excitatory synaptic vesicle within 30 nm of the active zone contacts one or more assembly. Further, intracellular structures were often shared between assemblies, entangling them to form larger complexes or association domains, often in small clusters of vesicles. Our findings suggest that transsynaptic assemblies physically connect the three compartments, allow for coordinated molecular organization, and may combine to form specialized functional association domains, resembling the light-level nanocolumns.SIGNIFICANCE STATEMENT A recent tomographic study uncovered that receptor-like cleft structures align across the synapse. These aligned structures were designated as transsynaptic assemblies and demonstrate the coordinated organization of synaptic transmission molecules between compartments. Our present tomographic study expands on the definition of transsynaptic assemblies by analyzing the three-dimensional distribution and connectivity of all cleft-spanning structures and their connected intracellular structures. While one-to-one component alignment occurs across the synapse, we find that many assemblies share components, leading to a complex entanglement of assemblies, typically around clusters of synaptic vesicles. Transsynaptic assemblies appear to form domains which may be the structural basis for alignment of molecular nanodomains into synapse spanning nanocolumns described by super-resolution light microscopy.
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Affiliation(s)
- Andy A Cole
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
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2
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Hayashi S, Ohno N, Knott G, Molnár Z. Correlative light and volume electron microscopy to study brain development. Microscopy (Oxf) 2023; 72:279-286. [PMID: 36620906 DOI: 10.1093/jmicro/dfad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
Recent advances in volume electron microscopy (EM) have been driving our thorough understanding of the brain architecture. Volume EM becomes increasingly powerful when cells and their subcellular structures that are imaged in light microscopy are correlated to those in ultramicrographs obtained with EM. This correlative approach, called correlative light and volume electron microscopy (vCLEM), is used to link three-dimensional ultrastructural information with physiological data such as intracellular Ca2+ dynamics. Genetic tools to express fluorescent proteins and/or an engineered form of a soybean ascorbate peroxidase allow us to perform vCLEM using natural landmarks including blood vessels without immunohistochemical staining. This immunostaining-free vCLEM has been successfully employed in two-photon Ca2+ imaging in vivo as well as in studying complex synaptic connections in thalamic neurons that receive a variety of specialized inputs from the cerebral cortex. In this mini-review, we overview how volume EM and vCLEM have contributed to studying the developmental processes of the brain. We also discuss potential applications of genetic manipulation of target cells using clustered regularly interspaced short palindromic repeats-associated protein 9 and subsequent volume EM to the analysis of protein localization as well as to loss-of-function studies of genes regulating brain development. We give examples for the combinatorial usage of genetic tools with vCLEM that will further enhance our understanding of regulatory mechanisms underlying brain development.
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Affiliation(s)
- Shuichi Hayashi
- Department of Anatomy, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
- Division of Ultrastructural Research, National Institute for Physiological Sciences, 5-1 Higashiyama Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Graham Knott
- Biological Electron Microscopy Facility, Faculty of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Route Cantonale, Lausanne CH-1015, Switzerland
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
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3
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Chen X, Crosby KC, Feng A, Purkey AM, Aronova MA, Winters CA, Crocker VT, Leapman RD, Reese TS, Dell’Acqua ML. Palmitoylation of A-kinase anchoring protein 79/150 modulates its nanoscale organization, trafficking, and mobility in postsynaptic spines. Front Synaptic Neurosci 2022; 14:1004154. [PMID: 36186623 PMCID: PMC9521714 DOI: 10.3389/fnsyn.2022.1004154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
A-kinase anchoring protein 79-human/150-rodent (AKAP79/150) organizes signaling proteins to control synaptic plasticity. AKAP79/150 associates with the plasma membrane and endosomes through its N-terminal domain that contains three polybasic regions and two Cys residues that are reversibly palmitoylated. Mutations abolishing palmitoylation (AKAP79/150 CS) reduce its endosomal localization and association with the postsynaptic density (PSD). Here we combined advanced light and electron microscopy (EM) to characterize the effects of AKAP79/150 palmitoylation on its postsynaptic nanoscale organization, trafficking, and mobility in hippocampal neurons. Immunogold EM revealed prominent extrasynaptic membrane AKAP150 labeling with less labeling at the PSD. The label was at greater distances from the spine membrane for AKAP150 CS than WT in the PSD but not in extra-synaptic locations. Immunogold EM of GFP-tagged AKAP79 WT showed that AKAP79 adopts a vertical, extended conformation at the PSD with its N-terminus at the membrane, in contrast to extrasynaptic locations where it adopts a compact or open configurations of its N- and C-termini with parallel orientation to the membrane. In contrast, GFP-tagged AKAP79 CS was displaced from the PSD coincident with disruption of its vertical orientation, while proximity and orientation with respect to the extra-synaptic membrane was less impacted. Single-molecule localization microscopy (SMLM) revealed a heterogeneous distribution of AKAP150 with distinct high-density, nano-scale regions (HDRs) overlapping the PSD but more prominently located in the extrasynaptic membrane for WT and the CS mutant. Thick section scanning transmission electron microscopy (STEM) tomography revealed AKAP150 immunogold clusters similar in size to HDRs seen by SMLM and more AKAP150 labeled endosomes in spines for WT than for CS, consistent with the requirement for AKAP palmitoylation in endosomal trafficking. Hidden Markov modeling of single molecule tracking data revealed a bound/immobile fraction and two mobile fractions for AKAP79 in spines, with the CS mutant having shorter dwell times and faster transition rates between states than WT, suggesting that palmitoylation stabilizes individual AKAP molecules in various spine subpopulations. These data demonstrate that palmitoylation fine tunes the nanoscale localization, mobility, and trafficking of AKAP79/150 in dendritic spines, which might have profound effects on its regulation of synaptic plasticity.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Xiaobing Chen,
| | - Kevin C. Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Austin Feng
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alicia M. Purkey
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Maria A. Aronova
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Christine A. Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Virginia T. Crocker
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Richard D. Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
- Mark L. Dell’Acqua,
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4
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Lyu X, Wang J, Wang J, Yin YS, Zhu Y, Li LL, Huang S, Peng S, Xue B, Liao R, Wang SQ, Long M, Wohland T, Chua BT, Sun Y, Li P, Chen XW, Xu L, Chen FJ, Li P. A gel-like condensation of Cidec generates lipid-permeable plates for lipid droplet fusion. Dev Cell 2021; 56:2592-2606.e7. [PMID: 34508658 DOI: 10.1016/j.devcel.2021.08.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 05/02/2021] [Accepted: 08/17/2021] [Indexed: 10/20/2022]
Abstract
Membrane contact between intracellular organelles is important in mediating organelle communication. However, the assembly of molecular machinery at membrane contact site and its internal organization correlating with its functional activity remain unclear. Here, we demonstrate that a gel-like condensation of Cidec, a crucial protein for obesity development by facilitating lipid droplet (LD) fusion, occurs at the LD-LD contact site (LDCS) through phase separation. The homomeric interaction between the multivalent N terminus of Cidec is sufficient to promote its phase separation both in vivo and in vitro. Interestingly, Cidec condensation at LDCSs generates highly plastic and lipid-permeable fusion plates that are geometrically constrained by donor LDs. In addition, Cidec condensates are distributed unevenly in the fusion plate generating stochastic sub-compartments that may represent unique lipid passageways during LD fusion. We have thus uncovered the organization and functional significance of geometry-constrained Cidec phase separation in mediating LD fusion and lipid homeostasis.
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Affiliation(s)
- Xuchao Lyu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jia Wang
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianqin Wang
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ye-Sheng Yin
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yun Zhu
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Lin-Lin Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Shuangru Huang
- Departments of Biological Sciences and Chemistry and NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore
| | - Shuang Peng
- Institute of Mechanics, Chinese Academy of Sciences, No.15 Beisihuanxi Road, Beijing 100190, China
| | - Boxin Xue
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Rongyu Liao
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shi-Qiang Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Mian Long
- Institute of Mechanics, Chinese Academy of Sciences, No.15 Beisihuanxi Road, Beijing 100190, China
| | - Thorsten Wohland
- Departments of Biological Sciences and Chemistry and NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117557, Singapore
| | - Boon Tin Chua
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yujie Sun
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Pilong Li
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiao-Wei Chen
- State Key Laboratory of Membrane Biology, Center for Life Sciences and Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing 100101, China
| | - Li Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shanghai Qi Zhi Institute, Shanghai 200030, China
| | - Feng-Jung Chen
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai 200032, China; Shanghai Qi Zhi Institute, Shanghai 200030, China.
| | - Peng Li
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Shanghai Qi Zhi Institute, Shanghai 200030, China.
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5
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Luo T, Deng L, Li A, Zhou C, Shao S, Sun Q, Gong H, Yang X, Li X. Scalable Resin Embedding Method for Large-Volume Brain Tissues with High Fluorescence Preservation Capacity. iScience 2020; 23:101717. [PMID: 33196032 PMCID: PMC7645060 DOI: 10.1016/j.isci.2020.101717] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 01/15/2023] Open
Abstract
Resin embedding is widely used to dissect the fine structure of bio-tissue with electron and optical microscopy. However, it is difficult to embed large-volume tissues with resin. Here, we modified the formula of LR-White resin to prevent the sample cracking during polymerization process and applied this method to the intact brains of mouse, ferret, and macaque. Meanwhile, we increased the fluorescence preservation rate for green fluorescent protein (GFP) from 73 ± 4.0% to 126 ± 3.0% and tdTomato from 60 ± 3.3% to 117 ± 2.8%. Combined with the whole-brain imaging system, we acquired the cytoarchitectonic information and the circuit information such as individual axon and boutons which were labeled with multiple fluorescent proteins. This method shows great potential in the study of continuous fine microstructure information in large-volume tissues from different species, which can facilitate the neuroscience research and help the understanding of the structure-function relationship in complex bio-tissues. Modified LR-White resin embedding was proposed to embed large-volume tissues Retarder α-methyl-styrene was added to prevent cracking during polymerization Resin formula was modified to preserve multiple fluorescent proteins Microstructure information was acquired from the brains of different species
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Affiliation(s)
- Ting Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Lei Deng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Anan Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou 215125, China
| | - Can Zhou
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shuai Shao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Qingtao Sun
- HUST-Suzhou Institute for Brainsmatics, Suzhou 215125, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou 215125, China
| | - Xiaoquan Yang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou 215125, China
| | - Xiangning Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, #1037, Luoyu Road, Wuhan, Hubei 430074, China.,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou 215125, China
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6
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Guo SM, Veneziano R, Gordonov S, Li L, Danielson E, Perez de Arce K, Park D, Kulesa AB, Wamhoff EC, Blainey PC, Boyden ES, Cottrell JR, Bathe M. Multiplexed and high-throughput neuronal fluorescence imaging with diffusible probes. Nat Commun 2019; 10:4377. [PMID: 31558769 PMCID: PMC6763432 DOI: 10.1038/s41467-019-12372-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/03/2019] [Indexed: 12/29/2022] Open
Abstract
Synapses contain hundreds of distinct proteins whose heterogeneous expression levels are determinants of synaptic plasticity and signal transmission relevant to a range of diseases. Here, we use diffusible nucleic acid imaging probes to profile neuronal synapses using multiplexed confocal and super-resolution microscopy. Confocal imaging is performed using high-affinity locked nucleic acid imaging probes that stably yet reversibly bind to oligonucleotides conjugated to antibodies and peptides. Super-resolution PAINT imaging of the same targets is performed using low-affinity DNA imaging probes to resolve nanometer-scale synaptic protein organization across nine distinct protein targets. Our approach enables the quantitative analysis of thousands of synapses in neuronal culture to identify putative synaptic sub-types and co-localization patterns from one dozen proteins. Application to characterize synaptic reorganization following neuronal activity blockade reveals coordinated upregulation of the post-synaptic proteins PSD-95, SHANK3 and Homer-1b/c, as well as increased correlation between synaptic markers in the active and synaptic vesicle zones.
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Affiliation(s)
- Syuan-Ming Guo
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Remi Veneziano
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Simon Gordonov
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Li Li
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Eric Danielson
- Department of Biological Engineering, MIT, Cambridge, MA, USA
| | - Karen Perez de Arce
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Anthony B Kulesa
- Department of Biological Engineering, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Paul C Blainey
- Department of Biological Engineering, MIT, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Edward S Boyden
- Department of Biological Engineering, MIT, Cambridge, MA, USA
- Media Lab, MIT, Cambridge, MA, USA
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Mark Bathe
- Department of Biological Engineering, MIT, Cambridge, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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7
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Jiang R, Zhang J, Zou S, Jia S, Leng X, Qi Y, Zou X, Shen B, Li W, Lu W, Zhong H. Electron Acceptive Mass Tag for Mass Spectrometric Imaging-Guided Synergistic Targeting to Mice Brain Glutamate Receptors. ACS Chem Neurosci 2019; 10:757-767. [PMID: 30576595 DOI: 10.1021/acschemneuro.8b00580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Dysfunctional glutamate receptors (GluRs) have been implicated in neurological disorders and injuries. Hetero-tetrameric assemblies of different GluR subunits or splicing variants have distinct spatiotemporal expression patterns and pharmacological properties. Mass spectrometric imaging of GluRs-targeted small molecules is important for determining the regional preferences of these compounds. We report herein the development of a mass tag covalently bonded with glutamate or N-methyl-d-aspartate that functions as both an electron acceptor to generate mass spectrometric signals on irradiated (Bi2O3)0.07(CoO)0.03(ZnO)0.9 nanoparticles with the third harmonic (355 nm) of Nd3+:YAG laser and as the core component to target bilobed clamshell-like structures of GluRs. In this approach, different molecules produce the same tag ion. It provides a new avenue for quantitative assessment of spatial densities of different compounds, which cannot be achieved with well-established stable isotope labeling technique due to different ionization efficiency of different compounds. Various coexisting endogenous molecules are also simultaneously detected for investigation of overall physiological changes induced by these compounds. Because semiconductors do not generate background peaks, this method eliminates interferences from organic matrix materials that are used in regular MALDI (matrix assisted laser desorption ionization). The localized ionization provides high spatial resolution that can be down to sub-micrometers.
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Affiliation(s)
- Ruowei Jiang
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Juan Zhang
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Si Zou
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Shanshan Jia
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Xiebin Leng
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Yinghua Qi
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Xuekun Zou
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Baojie Shen
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Weidan Li
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Wenting Lu
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
| | - Hongying Zhong
- Mass Spectrometry Center for Structural Identification of Biological Molecules and Precision Medicine Institute of Public Health and Molecular Medicine Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P. R. China
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8
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Chen X, Winters C, Crocker V, Lazarou M, Sousa AA, Leapman RD, Reese TS. Identification of PSD-95 in the Postsynaptic Density Using MiniSOG and EM Tomography. Front Neuroanat 2018; 12:107. [PMID: 30581381 PMCID: PMC6292990 DOI: 10.3389/fnana.2018.00107] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022] Open
Abstract
Combining tomography with electron microscopy (EM) produces images at definition sufficient to visualize individual protein molecules or molecular complexes in intact neurons. When freeze-substituted hippocampal cultures in plastic sections are imaged by EM tomography, detailed structures emerging from 3D reconstructions reveal putative glutamate receptors and membrane-associated filaments containing scaffolding proteins such as postsynaptic density (PSD)-95 family proteins based on their size, shape, and known distributions. In limited instances, structures can be identified with enhanced immuno-Nanogold labeling after light fixation and subsequent freeze-substitution. Molecular identification of structure can be corroborated in their absence after acute protein knockdown or gene knockout. However, additional labeling methods linking EM level structure to molecules in tomograms are needed. A recent development for labeling structures for TEM employs expression of endogenous proteins carrying a green fluorescent tag, miniSOG, to photoconvert diaminobenzidine (DAB) into osmiophilic polymers. This approach requires initial mild chemical fixation but many of structural features in neurons can still be discerned in EM tomograms. The photoreaction product, which appears as electron-dense, fine precipitates decorating protein structures in neurons, may diffuse to fill cytoplasm of spines, thus obscuring specific localization of proteins tagged with miniSOG. Here we develop an approach to minimize molecular diffusion of the DAB photoreaction product in neurons, which allows miniSOG tagged molecule/complexes to be identified in tomograms. The examples reveal electron-dense clusters of reaction product labeling membrane-associated vertical filaments, corresponding to the site of miniSOG fused at the C-terminal end of PSD-95-miniSOG, allowing identification of PSD-95 vertical filaments at the PSD. This approach, which results in considerable improvement in the precision of labeling PSD-95 in tomograms without complications due to the presence of antibody complexes in immunogold labeling, may be applicable for identifying other synaptic proteins in intact neurons.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Christine Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Virginia Crocker
- EM Facility, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Michael Lazarou
- Surgical Neurology Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Alioscka A Sousa
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Richard D Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
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9
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Ren M, Tian J, Zhao P, Luo J, Feng Z, Gong H, Li X. Simultaneous Acquisition of Multicolor Information From Neural Circuits in Resin-Embedded Samples. Front Neurosci 2018; 12:885. [PMID: 30555296 PMCID: PMC6284031 DOI: 10.3389/fnins.2018.00885] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Resin embedding has been widely used for precise imaging of fluorescently labeled biological samples with optical and electron microscopy. The low preservation rate of fluorescence, especially for red fluorescent proteins, has limited the application of resin embedding in multifluorescent protein-labeled samples. Here, we optimized the embedding method to retain the intensity of multiple fluorescent proteins during resin embedding. By reducing the polymerization temperature from 50 to 35°C and adding a fluorescent protein protection reagent during the embedding process, we successfully increased the fluorescence preservation rate by nearly twofold for red fluorescent proteins, including tdTomato, mCherry, and DsRed. Meanwhile, the background fluorescence decreased significantly in the optimized embedding method. This method is suitable not only for red fluorescent protein-labeled samples but also for blue (BFP) and green fluorescent protein (GFP)-labeled samples. We embedded brains labeled with BFP, DsRed, and GFP via AAV and rabies virus and acquired the distribution of input neurons to different cortical areas. With GFP/tdTomato double-labeled samples in resin, we obtained the cholinergic projectome of the pedunculopontine tegmental nucleus (PPTg) and the distribution of cholinergic neurons at single-neuron resolution in the whole brain simultaneously. Input cholinergic terminals from the PPTg were found to innervate the cholinergic soma and fiber in the neocortex, basal forebrain and brainstem, indicating that local cholinergic neurons received long-range cholinergic modulation from the midbrain. Our optimized method is useful for embedding multicolor fluorescent protein-labeled samples to acquire multidimensional structural information on neural circuits at single-neuron resolution in the whole brain.
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Affiliation(s)
- Miao Ren
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Jiaojiao Tian
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Peilin Zhao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Jialiang Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Zhao Feng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou, China
| | - Xiangning Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.,MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, Suzhou, China
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10
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Chakrabarti R, Michanski S, Wichmann C. Vesicle sub-pool organization at inner hair cell ribbon synapses. EMBO Rep 2018; 19:embr.201744937. [PMID: 30201800 DOI: 10.15252/embr.201744937] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/07/2018] [Accepted: 08/21/2018] [Indexed: 02/02/2023] Open
Abstract
The afferent inner hair cell synapse harbors the synaptic ribbon, which ensures a constant vesicle supply. Synaptic vesicles (SVs) are arranged in morphologically discernable pools, linked via filaments to the ribbon or the presynaptic membrane. We propose that filaments play a major role in SV resupply and exocytosis at the ribbon. Using advanced electron microscopy, we demonstrate that SVs are organized in sub-pools defined by the filament number per vesicle and its connections. Upon stimulation, SVs increasingly linked to other vesicles and to the ribbon, whereas single-tethered SVs dominated at the membrane. Mutant mice for the hair cell protein otoferlin (pachanga, Otof Pga/Pga ) are profoundly deaf with reduced sustained release, serving as a model to investigate the SV replenishment at IHCs. Upon stimulation, multiple-tethered and docked vesicles (rarely observed in wild-type) accumulated at Otof Pga/Pga active zones due to an impairment downstream of docking. Conclusively, vesicles are organized in sub-pools at ribbon-type active zones by filaments to support vesicle supply, transport, and finally release.
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Affiliation(s)
- Rituparna Chakrabarti
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Susann Michanski
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany.,Georg-August University School of Science, Göttingen, Germany
| | - Carolin Wichmann
- Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany .,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany
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11
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Smith CL, Reese TS. Adherens Junctions Modulate Diffusion between Epithelial Cells in Trichoplax adhaerens. THE BIOLOGICAL BULLETIN 2016; 231:216-224. [PMID: 28048952 DOI: 10.1086/691069] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Trichoplax adhaerens is the sole named member of Placozoa, an ancient metazoan phylum. This coin-shaped animal glides on ventral cilia to find and digest algae on the substrate. It has only six cell types, all but two of which are incorporated into the epithelium that encloses it. The upper epithelium is thin, composed of a pavement of relatively large polygonal disks, each bearing a cilium. The lower epithelium is thick and composed primarily of narrow ciliated cells that power locomotion. Interspersed among these cells are two different secretory cells: one containing large lipophilic granules that, when released, lyse algae under the animal; the other, less abundant, is replete with smaller secretory granules containing neuropeptides. All cells within both epithelia are joined by adherens junctions that are stabilized by apical actin networks. Cells are held in place during shape changes or under osmotic stress, but dissociate in low calcium. Neither tight, septate, nor gap junctions are evident, leaving only the adherens junction to control the permeability of the epithelium. Small (<4 kDa) fluorescent dextrans introduced into artificial seawater readily penetrate into the animal between the cells. Larger dextrans enter slowly, except in animals treated with reduced calcium, indicating that the adherens junctions form a circumferential belt around each cell that impedes diffusion into the animal. During feeding, the limited permeability of the adherens junctions helps to confine material released from lysed algae within the narrow space under the animal, where it is absorbed by endocytosis.
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12
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Zhan H, Bruckner J, Zhang Z, O’Connor-Giles K. Three-dimensional imaging of Drosophila motor synapses reveals ultrastructural organizational patterns. J Neurogenet 2016; 30:237-246. [PMID: 27981875 PMCID: PMC5281062 DOI: 10.1080/01677063.2016.1253693] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/22/2016] [Accepted: 10/24/2016] [Indexed: 01/18/2023]
Abstract
We combined cryo-preservation of intact Drosophila larvae and electron tomography with comprehensive segmentation of key features to reconstruct the complete ultrastructure of a model glutamatergic synapse in a near-to-native state. Presynaptically, we detail a complex network of filaments that connects and organizes synaptic vesicles. We link the complexity of this synaptic vesicle network to proximity to the active zone cytomatrix, consistent with the model that these protein structures function together to regulate synaptic vesicle pools. We identify a net-shaped network of electron-dense filaments spanning the synaptic cleft that suggests conserved organization of trans-synaptic adhesion complexes at excitatory synapses. Postsynaptically, we characterize a regular pattern of macromolecules that yields structural insights into the scaffolding of neurotransmitter receptors. Together, these analyses reveal an unexpected level of conservation in the nanoscale organization of diverse glutamatergic synapses and provide a structural foundation for understanding the molecular machines that regulate synaptic communication at a powerful model synapse.
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Affiliation(s)
- Hong Zhan
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Joseph Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Ziheng Zhang
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Kate O’Connor-Giles
- Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
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13
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A Network of Three Types of Filaments Organizes Synaptic Vesicles for Storage, Mobilization, and Docking. J Neurosci 2016; 36:3222-30. [PMID: 26985032 DOI: 10.1523/jneurosci.2939-15.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Synaptic transmission between neurons requires precise management of synaptic vesicles. While individual molecular components of the presynaptic terminal are well known, exactly how the molecules are organized into a molecular machine serving the storage and mobilization of synaptic vesicles to the active zone remains unclear. Here we report three filament types associated with synaptic vesicles in glutamatergic synapses revealed by electron microscope tomography in unstimulated, dissociated rat hippocampal neurons. One filament type, likely corresponding to the SNAREpin complex, extends from the active zone membrane and surrounds docked vesicles. A second filament type contacts all vesicles throughout the active zone and pairs vesicles together. On the third filament type, vesicles attach to side branches extending from the long filament core and form vesicle clusters that are distributed throughout the vesicle cloud and along the active zone membrane. Detailed analysis of presynaptic structure reveals how each of the three filament types interacts with synaptic vesicles, providing a means to traffic reserved and recycled vesicles from the cloud of vesicles into the docking position at the active zone. SIGNIFICANCE STATEMENT The formation and release of synaptic vesicles has been extensively investigated. Explanations of the release of synaptic vesicles generally begin with the movement of vesicles from the cloud into the synaptic active zone. However, the presynaptic terminal is filled with filamentous material that would appear to limit vesicular diffusion. Here, we provide a systematic description of three filament types connecting synaptic vesicles. A picture emerges illustrating how the cooperative attachment and release of these three filament types facilitate the movement of vesicles to the active zone to become docked in preparation for release.
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14
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Niclis JC, Murphy SV, Parkinson DY, Zedan A, Sathananthan AH, Cram DS, Heraud P. Three-dimensional imaging of human stem cells using soft X-ray tomography. J R Soc Interface 2016; 12:20150252. [PMID: 26063819 DOI: 10.1098/rsif.2015.0252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Three-dimensional imaging of human stem cells using transmission soft X-ray tomography (SXT) is presented for the first time. Major organelle types--nuclei, nucleoli, mitochondria, lysosomes and vesicles--were discriminated at approximately 50 nm spatial resolution without the use of contrast agents, on the basis of measured linear X-ray absorption coefficients and comparison of the size and shape of structures to transmission electron microscopy (TEM) images. In addition, SXT was used to visualize the distribution of a cell surface protein using gold-labelled antibody staining. We present the strengths of SXT, which include excellent spatial resolution (intermediate between that of TEM and light microscopy), the lack of the requirement for fixative or contrast agent that might perturb cellular morphology or produce imaging artefacts, and the ability to produce three-dimensional images of cells without microtome sectioning. Possible applications to studying the differentiation of human stem cells are discussed.
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Affiliation(s)
- J C Niclis
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia The Florey Institute of Neuroscience and Mental Health, Melbourne University, Parkville, Victoria 3052, Australia
| | - S V Murphy
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria 3800, Australia Wake Forest Baptist Medical Center, Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC, USA
| | - D Y Parkinson
- Advanced Light Source, Lawrence Berkeley National Laboratory, US Department of Energy, Berkeley, CA, USA
| | - A Zedan
- Advanced Light Source, Lawrence Berkeley National Laboratory, US Department of Energy, Berkeley, CA, USA
| | - A H Sathananthan
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia
| | - D S Cram
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia
| | - P Heraud
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia Centre for Biospectroscopy, School of Chemistry, Monash University, Melbourne, Victoria, Australia
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15
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PSD-95 family MAGUKs are essential for anchoring AMPA and NMDA receptor complexes at the postsynaptic density. Proc Natl Acad Sci U S A 2015; 112:E6983-92. [PMID: 26604311 DOI: 10.1073/pnas.1517045112] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The postsynaptic density (PSD)-95 family of membrane-associated guanylate kinases (MAGUKs) are major scaffolding proteins at the PSD in glutamatergic excitatory synapses, where they maintain and modulate synaptic strength. How MAGUKs underlie synaptic strength at the molecular level is still not well understood. Here, we explore the structural and functional roles of MAGUKs at hippocampal excitatory synapses by simultaneous knocking down PSD-95, PSD-93, and synapse-associated protein (SAP)102 and combining electrophysiology and transmission electron microscopic (TEM) tomography imaging to analyze the resulting changes. Acute MAGUK knockdown greatly reduces synaptic transmission mediated by α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (AMPARs) and N-methyl-d-aspartate receptors (NMDARs). This knockdown leads to a significant rise in the number of silent synapses, diminishes the size of PSDs without changes in pre- or postsynaptic membrane, and depletes the number of membrane-associated PSD-95-like vertical filaments and transmembrane structures, identified as AMPARs and NMDARs by EM tomography. The differential distribution of these receptor-like structures and dependence of their abundance on PSD size matches that of AMPARs and NMDARs in the hippocampal synapses. The loss of these structures following MAGUK knockdown tracks the reduction in postsynaptic AMPAR and NMDAR transmission, confirming the structural identities of these two types of receptors. These results demonstrate that MAGUKs are required for anchoring both types of glutamate receptors at the PSD and are consistent with a structural model where MAGUKs, corresponding to membrane-associated vertical filaments, are the essential structural proteins that anchor and organize both types of glutamate receptors and govern the overall molecular organization of the PSD.
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16
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High B, Cole AA, Chen X, Reese TS. Electron microscopic tomography reveals discrete transcleft elements at excitatory and inhibitory synapses. Front Synaptic Neurosci 2015; 7:9. [PMID: 26113817 PMCID: PMC4461817 DOI: 10.3389/fnsyn.2015.00009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/28/2015] [Indexed: 12/24/2022] Open
Abstract
Electron microscopy has revealed an abundance of material in the clefts of synapses in the mammalian brain, and the biochemical and functional characteristics of proteins occupying synaptic clefts are well documented. However, the detailed spatial organization of the proteins in the synaptic clefts remains unclear. Electron microscope tomography provides a way to delineate and map the proteins spanning the synaptic cleft because freeze substitution preserves molecular details with sufficient contrast to visualize individual cleft proteins. Segmentation and rendering of electron dense material connected across the cleft reveals discrete structural elements that are readily classified into five types at excitatory synapses and four types at inhibitory synapses. Some transcleft elements resemble shapes and sizes of known proteins and could represent single dimers traversing the cleft. Some of the types of cleft elements at inhibitory synapses roughly matched the structure and proportional frequency of cleft elements at excitatory synapses, but the patterns of deployments in the cleft are quite different. Transcleft elements at excitatory synapses were often evenly dispersed in clefts of uniform (18 nm) width but some types show preference for the center or edges of the cleft. Transcleft elements at inhibitory synapses typically were confined to a peripheral region of the cleft where it narrowed to only 6 nm wide. Transcleft elements in both excitatory and inhibitory synapses typically avoid places where synaptic vesicles attach to the presynaptic membrane. These results illustrate that elements spanning synaptic clefts at excitatory and inhibitory synapses consist of distinct structures arranged by type in a specific but different manner at excitatory and inhibitory synapses.
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Affiliation(s)
- Brigit High
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Strokes, National Institutes of Health Bethesda, MD, USA
| | - Andy A Cole
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Strokes, National Institutes of Health Bethesda, MD, USA ; Department of Cell and Molecular Biology, Northwestern University Chicago, IL, USA
| | - Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Strokes, National Institutes of Health Bethesda, MD, USA
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Strokes, National Institutes of Health Bethesda, MD, USA
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17
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18
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Linsalata AE, Chen X, Winters CA, Reese TS. Electron tomography on γ-aminobutyric acid-ergic synapses reveals a discontinuous postsynaptic network of filaments. J Comp Neurol 2014; 522:921-36. [PMID: 23982982 DOI: 10.1002/cne.23453] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 08/05/2013] [Accepted: 08/13/2013] [Indexed: 12/16/2022]
Abstract
The regulation of synaptic strength at γ-aminobutyric acid (GABA)-ergic synapses is dependent on the dynamic capture, retention, and modulation of GABA A-type receptors by cytoplasmic proteins at GABAergic postsynaptic sites. How these proteins are oriented and organized in the postsynaptic cytoplasm is not yet established. To better understand these structures and gain further insight into the mechanisms by which they regulate receptor populations at postsynaptic sites, we utilized electron tomography to examine GABAergic synapses in dissociated rat hippocampal cultures. GABAergic synapses were identified and selected for tomography by using a set of criteria derived from the structure of immunogold-labeled GABAergic synapses. Tomography revealed a complex postsynaptic network composed of filaments that extend ∼ 100 nm into the cytoplasm from the postsynaptic membrane. The distribution of these postsynaptic filaments was strikingly similar to that of the immunogold label for gephyrin. Filaments were interconnected through uniform patterns of contact, forming complexes composed of 2-12 filaments each. Complexes did not link to form an integrated, continuous scaffold, suggesting that GABAergic postsynaptic specializations are less rigidly organized than glutamatergic postsynaptic densities.
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Affiliation(s)
- Alexander E Linsalata
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, 20892
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19
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Kavalali ET, Jorgensen EM. Visualizing presynaptic function. Nat Neurosci 2013; 17:10-6. [PMID: 24369372 DOI: 10.1038/nn.3578] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 10/14/2013] [Indexed: 12/15/2022]
Abstract
Synaptic communication in the nervous system is initiated by the fusion of synaptic vesicles with the presynaptic plasma membrane and subsequent neurotransmitter release. In the 1980s, this process was characterized by electron microscopy, albeit without the ability to follow processes in living cells. In the last two decades, fluorescence imaging methods have been developed that report synaptic vesicle fusion, endocytosis and recycling. These probes have provided unprecedented insight into synaptic vesicle trafficking in individual synaptic terminals and revealed heterogeneity in recycling pathways as well as synaptic vesicle populations. These methods either take advantage of uptake of fluorescent probes into recycling vesicles or exogenous expression of synaptic vesicle proteins tagged with a pH-sensitive fluorescent marker at regions facing the vesicle lumen. We provide an overview of these methods, with particular emphasis on the challenges associated with their use and the opportunities for future investigations.
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Affiliation(s)
- Ege T Kavalali
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Erik M Jorgensen
- 1] Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah, USA. [2] Department of Biology, University of Utah, Salt Lake City, Utah, USA
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20
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Kuwajima M, Spacek J, Harris KM. Beyond counts and shapes: studying pathology of dendritic spines in the context of the surrounding neuropil through serial section electron microscopy. Neuroscience 2013; 251:75-89. [PMID: 22561733 PMCID: PMC3535574 DOI: 10.1016/j.neuroscience.2012.04.061] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/16/2012] [Accepted: 04/20/2012] [Indexed: 02/06/2023]
Abstract
Because dendritic spines are the sites of excitatory synapses, pathological changes in spine morphology should be considered as part of pathological changes in neuronal circuitry in the forms of synaptic connections and connectivity strength. In the past, spine pathology has usually been measured by changes in their number or shape. A more complete understanding of spine pathology requires visualization at the nanometer level to analyze how the changes in number and size affect their presynaptic partners and associated astrocytic processes, as well as organelles and other intracellular structures. Currently, serial section electron microscopy (ssEM) offers the best approach to address this issue because of its ability to image the volume of brain tissue at the nanometer resolution. Renewed interest in ssEM has led to recent technological advances in imaging techniques and improvements in computational tools indispensable for three-dimensional analyses of brain tissue volumes. Here we consider the small but growing literature that has used ssEM analysis to unravel ultrastructural changes in neuropil including dendritic spines. These findings have implications in altered synaptic connectivity and cell biological processes involved in neuropathology, and serve as anatomical substrates for understanding changes in network activity that may underlie clinical symptoms.
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Affiliation(s)
- Masaaki Kuwajima
- Center for Learning and Memory, The University of Texas at Austin
| | - Josef Spacek
- Charles University Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Kristen M. Harris
- Center for Learning and Memory, The University of Texas at Austin
- Section of Neurobiology, The University of Texas at Austin
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21
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Fogarty MJ, Hammond LA, Kanjhan R, Bellingham MC, Noakes PG. A method for the three-dimensional reconstruction of Neurobiotin™-filled neurons and the location of their synaptic inputs. Front Neural Circuits 2013; 7:153. [PMID: 24101895 PMCID: PMC3787200 DOI: 10.3389/fncir.2013.00153] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/12/2013] [Indexed: 12/15/2022] Open
Abstract
Here, we describe a robust method for mapping the number and type of neuro-chemically distinct synaptic inputs that a single reconstructed neuron receives. We have used individual hypoglossal motor neurons filled with Neurobiotin by semi-loose seal electroporation in thick brainstem slices. These filled motor neurons were then processed for excitatory and inhibitory synaptic inputs, using immunohistochemical-labeling procedures. For excitatory synapses, we used anti-VGLUT2 to locate glutamatergic pre-synaptic terminals and anti-PSD-95 to locate post-synaptic specializations on and within the surface of these filled motor neurons. For inhibitory synapses, we used anti-VGAT to locate GABAergic pre-synaptic terminals and anti-GABA-A receptor subunit α1 to locate the post-synaptic domain. The Neurobiotin-filled and immuno-labeled motor neuron was then processed for optical sectioning using confocal microscopy. The morphology of the motor neuron including its dendritic tree and the distribution of excitatory and inhibitory synapses were then determined by three-dimensional reconstruction using IMARIS software (Bitplane). Using surface rendering, fluorescence thresholding, and masking of unwanted immuno-labeling, tools found in IMARIS, we were able to obtain an accurate 3D structure of an individual neuron including the number and location of its glutamatergic and GABAergic synaptic inputs. The power of this method allows for a rapid morphological confirmation of the post-synaptic responses recorded by patch-clamp prior to Neurobiotin filling. Finally, we show that this method can be adapted to super-resolution microscopy techniques, which will enhance its applicability to the study of neural circuits at the level of synapses.
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Affiliation(s)
- Matthew J Fogarty
- School of Biomedical Sciences, The University of Queensland Brisbane, QLD, Australia
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Kim HW, Oh SH, Kim N, Nakazawa E, Rhyu IJ. Rapid method for electron tomographic reconstruction and three-dimensional modeling of the murine synapse using an automated fiducial marker-free system. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19 Suppl 5:182-187. [PMID: 23920202 DOI: 10.1017/s1431927613012622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electron tomography (ET) has recently afforded new insights into neuronal architecture. However, the tedious process of sample preparation, image acquisition, alignment, back projection, and additional segmentation process of ET repels beginners. We have tried Hitachi's commercial packages integrated with a Hitachi H-7650 TEM to examine the potential of using an automated fiducial-less approach for our own neuroscience research. Semi-thick sections (200-300 nm) were cut from blocks of fixed mouse (C57BL) cerebellum and prepared for ET. Sets of images were collected automatically as each section was tilted by 2° increments (±60°). "Virtual" image volumes were computationally reconstructed in three dimension (3D) with the EMIP software using either the commonly used "weighted back-projection" (WBP) method or "topography-based reconstruction" (TBR) algorithm for comparison. Computed tomograms using the TBR were more precisely reconstructed compared with the WBP method. Following reconstruction, the image volumes were imported into the 3D editing software A-View and segmented according to synaptic organization. The detailed synaptic components were revealed by very thin virtual image slices; 3D models of synapse structure could be constructed efficiently. Overall, this simplified system provided us with a graspable tool for pursuing ET studies in neuroscience.
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Affiliation(s)
- Hyun-wook Kim
- Department of Anatomy, College of Medicine, Korea University, 126-1 Anam-dong 5ga, Seongbuk-gu, Seoul 136-705, Korea
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23
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Burette AC, Lesperance T, Crum J, Martone M, Volkmann N, Ellisman MH, Weinberg RJ. Electron tomographic analysis of synaptic ultrastructure. J Comp Neurol 2013; 520:2697-711. [PMID: 22684938 DOI: 10.1002/cne.23067] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Synaptic function depends on interactions among sets of proteins that assemble into complex supramolecular machines. Molecular biology, electrophysiology, and live-cell imaging studies have provided tantalizing glimpses into the inner workings of the synapse, but fundamental questions remain regarding the functional organization of these "nano-machines." Electron tomography reveals the internal structure of synapses in three dimensions with exceptional spatial resolution. Here we report results from an electron tomographic study of axospinous synapses in neocortex and hippocampus of the adult rat, based on aldehyde-fixed material stabilized with tannic acid in lieu of postfixation with osmium tetroxide. Our results provide a new window into the structural basis of excitatory synaptic processing in the mammalian brain.
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Affiliation(s)
- Alain C Burette
- Department of Cell & Developmental Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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24
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Yang Z, Hu B, Zhang Y, Luo Q, Gong H. Development of a plastic embedding method for large-volume and fluorescent-protein-expressing tissues. PLoS One 2013; 8:e60877. [PMID: 23577174 PMCID: PMC3618106 DOI: 10.1371/journal.pone.0060877] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 03/04/2013] [Indexed: 02/02/2023] Open
Abstract
Fluorescent proteins serve as important biomarkers for visualizing both subcellular organelles in living cells and structural and functional details in large-volume tissues or organs. However, current techniques for plastic embedding are limited in their ability to preserve fluorescence while remaining suitable for micro-optical sectioning tomography of large-volume samples. In this study, we quantitatively evaluated the fluorescence preservation and penetration time of several commonly used resins in a Thy1-eYFP-H transgenic whole mouse brain, including glycol methacrylate (GMA), LR White, hydroxypropyl methacrylate (HPMA) and Unicryl. We found that HMPA embedding doubled the eYFP fluorescence intensity but required long durations of incubation for whole brain penetration. GMA, Unicryl and LR White each penetrated the brain rapidly but also led to variable quenching of eYFP fluorescence. Among the fast-penetrating resins, GMA preserved fluorescence better than LR White and Unicryl. We found that we could optimize the GMA formulation by reducing the polymerization temperature, removing 4-methoxyphenol and adjusting the pH of the resin solution to be alkaline. By optimizing the GMA formulation, we increased percentage of eYFP fluorescence preservation in GMA-embedded brains nearly two-fold. These results suggest that modified GMA is suitable for embedding large-volume tissues such as whole mouse brain and provide a novel approach for visualizing brain-wide networks.
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Affiliation(s)
- Zhongqin Yang
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Bihe Hu
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Yuhui Zhang
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- * E-mail:
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25
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Melo RCN, Paganoti GF, Dvorak AM, Weller PF. The internal architecture of leukocyte lipid body organelles captured by three-dimensional electron microscopy tomography. PLoS One 2013; 8:e59578. [PMID: 23555714 PMCID: PMC3608657 DOI: 10.1371/journal.pone.0059578] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/15/2013] [Indexed: 01/04/2023] Open
Abstract
Lipid bodies (LBs), also known as lipid droplets, are complex organelles of all eukaryotic cells linked to a variety of biological functions as well as to the development of human diseases. In cells from the immune system, such as eosinophils, neutrophils and macrophages, LBs are rapidly formed in the cytoplasm in response to inflammatory and infectious diseases and are sites of synthesis of eicosanoid lipid mediators. However, little is known about the structural organization of these organelles. It is unclear whether leukocyte LBs contain a hydrophobic core of neutral lipids as found in lipid droplets from adipocytes and how diverse proteins, including enzymes involved in eicosanoid formation, incorporate into LBs. Here, leukocyte LB ultrastructure was studied in detail by conventional transmission electron microscopy (TEM), immunogold EM and electron tomography. By careful analysis of the two-dimensional ultrastructure of LBs from human blood eosinophils under different conditions, we identified membranous structures within LBs in both resting and activated cells. Cyclooxygenase, a membrane inserted protein that catalyzes the first step in prostaglandin synthesis, was localized throughout the internum of LBs. We used fully automated dual-axis electron tomography to study the three-dimensional architecture of LBs in high resolution. By tracking 4 nm-thick serial digital sections we found that leukocyte LBs enclose an intricate system of membranes within their “cores”. After computational reconstruction, we showed that these membranes are organized as a network of tubules which resemble the endoplasmic reticulum (ER). Our findings explain how membrane-bound proteins interact and are spatially arranged within LB “cores” and support a model for LB formation by incorporating cytoplasmic membranes of the ER, instead of the conventional view that LBs emerge from the ER leaflets. This is important to understand the functional capabilities of leukocyte LBs in health and during diverse diseases in which these organelles are functionally involved.
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Affiliation(s)
- Rossana C. N. Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Guillherme F. Paganoti
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil
| | - Ann M. Dvorak
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter F. Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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26
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Lidke DS, Lidke KA. Advances in high-resolution imaging--techniques for three-dimensional imaging of cellular structures. J Cell Sci 2012; 125:2571-80. [PMID: 22685332 DOI: 10.1242/jcs.090027] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A fundamental goal in biology is to determine how cellular organization is coupled to function. To achieve this goal, a better understanding of organelle composition and structure is needed. Although visualization of cellular organelles using fluorescence or electron microscopy (EM) has become a common tool for the cell biologist, recent advances are providing a clearer picture of the cell than ever before. In particular, advanced light-microscopy techniques are achieving resolutions below the diffraction limit and EM tomography provides high-resolution three-dimensional (3D) images of cellular structures. The ability to perform both fluorescence and electron microscopy on the same sample (correlative light and electron microscopy, CLEM) makes it possible to identify where a fluorescently labeled protein is located with respect to organelle structures visualized by EM. Here, we review the current state of the art in 3D biological imaging techniques with a focus on recent advances in electron microscopy and fluorescence super-resolution techniques.
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Affiliation(s)
- Diane S Lidke
- Department of Pathology and Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM 87131, USA
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27
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Fera A, Farrington JE, Zimmerberg J, Reese TS. A negative stain for electron microscopic tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:331-335. [PMID: 22364718 PMCID: PMC3650645 DOI: 10.1017/s1431927611012797] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
While negative staining can provide detailed, two-dimensional images of biological structures, the potential of combining tomography with negative staining to provide three-dimensional views has yet to be fully realized. Basic requirements of a negative stain for tomography are that the density and atomic number of the stain are optimal, and that the stain does not degrade or rearrange with the intensive electron dose (~10⁶ e/nm²) needed to collect a full set of tomographic images. A commercially available, tungsten-based stain appears to satisfy these prerequisites. Comparison of the surface structure of negatively stained influenza A virus with previous structural results served to evaluate this negative stain. The combination of many projections of the same structure yielded detailed images of single proteins on the viral surface. Corresponding surface renderings are a good fit to images of the viral surface derived from cryomicroscopy as well as to the shapes of crystallized surface proteins. Negative stain tomography with the appropriate stain yields detailed images of individual molecules in their normal setting on the surface of the influenza A virus.
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Affiliation(s)
- Andrea Fera
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jane E. Farrington
- Laboratory of Cellular Molecular Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Joshua Zimmerberg
- Laboratory of Cellular Molecular Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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28
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Sheng M, Kim E. The postsynaptic organization of synapses. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a005678. [PMID: 22046028 DOI: 10.1101/cshperspect.a005678] [Citation(s) in RCA: 385] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The postsynaptic side of the synapse is specialized to receive the neurotransmitter signal released from the presynaptic terminal and transduce it into electrical and biochemical changes in the postsynaptic cell. The cardinal functional components of the postsynaptic specialization of excitatory and inhibitory synapses are the ionotropic receptors (ligand-gated channels) for glutamate and γ-aminobutyric acid (GABA), respectively. These receptor channels are concentrated at the postsynaptic membrane and embedded in a dense and rich protein network comprised of anchoring and scaffolding molecules, signaling enzymes, cytoskeletal components, as well as other membrane proteins. Excitatory and inhibitory postsynaptic specializations are quite different in molecular organization. The postsynaptic density of excitatory synapses is especially complex and dynamic in composition and regulation; it contains hundreds of different proteins, many of which are required for cognitive function and implicated in psychiatric illness.
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Affiliation(s)
- Morgan Sheng
- The Department of Neuroscience, Genentech Incorporated, San Francisco, California 94080, USA
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29
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Volume electron microscopy for neuronal circuit reconstruction. Curr Opin Neurobiol 2011; 22:154-61. [PMID: 22119321 DOI: 10.1016/j.conb.2011.10.022] [Citation(s) in RCA: 210] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 10/19/2011] [Accepted: 10/27/2011] [Indexed: 11/23/2022]
Abstract
The last decade has seen a rapid increase in the number of tools to acquire volume electron microscopy (EM) data. Several new scanning EM (SEM) imaging methods have emerged, and classical transmission EM (TEM) methods are being scaled up and automated. Here we summarize the new methods for acquiring large EM volumes, and discuss the tradeoffs in terms of resolution, acquisition speed, and reliability. We then assess each method's applicability to the problem of reconstructing anatomical connectivity between neurons, considering both the current capabilities and future prospects of the method. Finally, we argue that neuronal 'wiring diagrams' are likely necessary, but not sufficient, to understand the operation of most neuronal circuits: volume EM imaging will likely find its best application in combination with other methods in neuroscience, such as molecular biology, optogenetics, and physiology.
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30
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MacGillavry HD, Kerr JM, Blanpied TA. Lateral organization of the postsynaptic density. Mol Cell Neurosci 2011; 48:321-31. [PMID: 21920440 DOI: 10.1016/j.mcn.2011.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 08/31/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022] Open
Abstract
Fast excitatory synaptic transmission is mediated by AMPA-type glutamate receptors (AMPARs). It is widely accepted that the number of AMPARs in the postsynaptic density (PSD) critically determines the efficiency of synaptic transmission, but an unappreciated aspect of synapse organization is the lateral positioning of AMPARs within the PSD, that is, their distribution across the face of a single synapse. Receptor lateral positioning is important in a number of processes, most notably because alignment with presynaptic release sites heavily influences the probability of receptor activation. In this review, we summarize current understanding of the mechanisms that dynamically control the subsynaptic positioning of AMPARs. This field is still at early stages, but the recent wave of developments in super-resolution microscopy, synapse tomography, and computational modeling now enable the study of lateral protein distribution and dynamics within the nanometer-scale boundaries of the PSD. We discuss data available measuring the lateral distribution of glutamate receptors and scaffold proteins within the PSD, and discuss potential mechanisms that might give rise to these patterns. Elucidating the mechanisms that underlie the lateral organization of the PSD will be critical to improve our understanding of synaptic processes whose disruption may be unexpectedly important in neurological disorders. This article is part of a Special Issue entitled Membrane Trafficking and Cytoskeletal Dynamics in 'Neuronal Function'.
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Affiliation(s)
- Harold D MacGillavry
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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31
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Abstract
PSD-95, a membrane-associated guanylate kinase, is the major scaffolding protein in the excitatory postsynaptic density (PSD) and a potent regulator of synaptic strength. Here we show that PSD-95 is in an extended configuration and positioned into regular arrays of vertical filaments that contact both glutamate receptors and orthogonal horizontal elements layered deep inside the PSD in rat hippocampal spine synapses. RNA interference knockdown of PSD-95 leads to loss of entire patches of PSD material, and electron microscopy tomography shows that the patchy loss correlates with loss of PSD-95-containing vertical filaments, horizontal elements associated with the vertical filaments, and putative AMPA receptor-type, but not NMDA receptor-type, structures. These observations show that the orthogonal molecular scaffold constructed from PSD-95-containing vertical filaments and their associated horizontal elements is essential for sustaining the three-dimensional molecular organization of the PSD. Our findings provide a structural basis for understanding the functional role of PSD-95 at the PSD.
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32
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Dani A, Huang B, Bergan J, Dulac C, Zhuang X. Superresolution imaging of chemical synapses in the brain. Neuron 2011; 68:843-56. [PMID: 21144999 PMCID: PMC3057101 DOI: 10.1016/j.neuron.2010.11.021] [Citation(s) in RCA: 476] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2010] [Indexed: 12/30/2022]
Abstract
Determination of the molecular architecture of synapses requires nanoscopic image resolution and specific molecular recognition, a task that has so far defied many conventional imaging approaches. Here, we present a superresolution fluorescence imaging method to visualize the molecular architecture of synapses in the brain. Using multicolor, three-dimensional stochastic optical reconstruction microscopy, the distributions of synaptic proteins can be measured with nanometer precision. Furthermore, the wide-field, volumetric imaging method enables high-throughput, quantitative analysis of a large number of synapses from different brain regions. To demonstrate the capabilities of this approach, we have determined the organization of ten protein components of the presynaptic active zone and the postsynaptic density. Variations in synapse morphology, neurotransmitter receptor composition, and receptor distribution were observed both among synapses and across different brain regions. Combination with optogenetics further allowed molecular events associated with synaptic plasticity to be resolved at the single-synapse level.
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Affiliation(s)
- Adish Dani
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Bo Huang
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Department of Physics, Harvard University, Cambridge, MA 02138
| | - Joseph Bergan
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Catherine Dulac
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
- Correspondence: ,
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Department of Physics, Harvard University, Cambridge, MA 02138
- Correspondence: ,
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33
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Melo RC, Weller PF. Piecemeal degranulation in human eosinophils: a distinct secretion mechanism underlying inflammatory responses. Histol Histopathol 2010; 25:1341-54. [PMID: 20712018 PMCID: PMC3427618 DOI: 10.14670/hh-25.1341] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Secretion is a fundamental cell process underlying different physiological and pathological events. In cells from the human immune system such as eosinophils, secretion of mediators generally occurs by means of piecemeal degranulation, an unconventional secretory pathway characterized by vesicular transport of small packets of materials from the cytoplasmic secretory granules to the cell surface. During piecemeal degranulation in eosinophils, a distinct transport vesicle system, which includes large, pleiomorphic vesiculo-tubular carriers is mobilized and enables regulated release of granule-stored proteins such as cytokines and major basic protein. Piecemeal degranulation underlies distinct functions of eosinophils as effector and immunoregulatory cells. This review focuses on the structural and functional advances that have been made over the last years concerning the intracellular trafficking and secretion of eosinophil proteins by piecemeal degranulation during inflammatory responses.
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Affiliation(s)
- Rossana C.N. Melo
- Laboratory of Cellular Biology, Department of Biology, Federal University of Juiz de Fora, UFJF, Juiz de Fora, MG, Brazil
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Peter F. Weller
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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34
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Dani A, Huang B. New resolving power for light microscopy: applications to neurobiology. Curr Opin Neurobiol 2010; 20:648-52. [PMID: 20728340 DOI: 10.1016/j.conb.2010.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 12/16/2022]
Abstract
The recent invention of super-resolution fluorescence microscopy brings more than an order of magnitude gain in the spatial resolution of light microscopy. New opportunities keep emerging with the multicolor, three-dimensional, and live imaging functionalities gained in the past three years. The power of this technology has been demonstrated by imaging the organization of organelles and molecular complexes, with recent applications increasingly showing its potential in neurobiology. These developments are exemplified by the visualization of components inside dendritic spines to fine morphologies of neurons. In combination with correlative electron microscopy, functional imaging, and electrical/optogenetic stimulation tools, super-resolution fluorescence microscopy has the potential to provide further insights ranging from the molecular details of neurons up to the functional mechanisms of neuronal circuits.
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Affiliation(s)
- Adish Dani
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, USA.
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35
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Linberg KA, Lewis GP, Fisher SK. Retraction and remodeling of rod spherules are early events following experimental retinal detachment: an ultrastructural study using serial sections. Mol Vis 2009; 15:10-25. [PMID: 19137070 PMCID: PMC2614448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Accepted: 12/31/2008] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To describe changes induced by retinal detachment in the ultrastructure and organization of rod terminals and their connections with B-type horizontal cell (HC) axon terminals and rod bipolar cell (RB) dendrites. METHODS Sections from control, 3 day, 7 day, and 28 day detached feline retinas were prepared for confocal immunofluorescence, light microscopy, and electron microscopy (EM). In addition, 100 mum-thick vibratome sections were immunolabeled with markers for photoreceptor terminals, HCs, and RBs. More than 40 rod spherules were studied in 90 nm-thick serial sections by transmission EM to greater detail changes in their ultrastructure and innervation. RESULTS Following retinal detachment, many rod terminals retracted varying distances toward their respective cell bodies in the outer nuclear layer (ONL). In retinas detached for 1 to 4 weeks, an altered synaptic vesicle population and associated ribbons were found in all retracting terminals. Many rod somata in the distal ONL seemed to lack synaptic terminal structures altogether. In a retina detached for 1 week, EM showed that less than half of the retracted terminals remain in contact with RB dendrites. In contrast, almost every surviving spherule was contacted by neurite outgrowths from the axon terminals of the B-type HC. Although retracted spherules had several presynaptic structures similar to those in normal retina, numerous changes occurred in their overall synaptic architecture. The spherule's invagination was shallower, contained fewer postsynaptic processes, and often had "opened," allowing swollen HC processes apposing the synaptic ribbon to directly contact other processes of the outer plexiform layer (OPL) neuropil. Whereas in normal cat retina each HC "lobe" comes from a different axon terminal system, after detachment, the opposing lateral elements can stem from the same terminal. The innervating RB dendrites that branched off stout RB dendritic trunks that extended up into the ONL were thinner than normal, unbranched, often electron dense, and lacked organelles. When present, most merely lay adjacent to retracting spherules rather than enter any synaptic invagination that might still occur. CONCLUSIONS Immunocytochemistry enabled RB and HC neurites to appear postsynaptic to retracted rod terminals. However, at the ultrastructural level, HCs seemed to more consistently retain connection with the retracted spherules than the RBs. The highly conserved architecture of the rod spherule was lost as the invagination opened and postsynaptic contacts became fewer. It would seem that the lack of RB central elements as well as the drastic alterations in the architecture of most retracted terminals would necessarily alter the physiology of this complex synapse.
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Affiliation(s)
- Kenneth A. Linberg
- Neuroscience Research Institute, University of California, Santa Barbara, CA
| | - Geoffrey P. Lewis
- Neuroscience Research Institute, University of California, Santa Barbara, CA
| | - Steven K. Fisher
- Neuroscience Research Institute, University of California, Santa Barbara, CA,Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA
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