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Vaidya RM, Zhang J, Nall D, Lee Y, Chang Kim E, Ma D, Huang F, Nonaka H, Kiyonaka S, Hamachi I, Jung Chung H, Selvin PR. Nanoscale organization is changed in native, surface AMPARs by mouse brain region and tauopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.22.604547. [PMID: 39091751 PMCID: PMC11291066 DOI: 10.1101/2024.07.22.604547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Synaptic AMPA receptors (AMPARs) on neuronal plasma membranes are correlated with learning and memory. Using a unique labeling and super-resolution imaging, we have visualized the nanoscale synaptic and extra-synaptic organization of native surface AMPARs for the first time in mouse brain slices as a function of brain region and tauopathy. We find that the fraction of surface AMPARs organized in synaptic clusters is two-times smaller in the hippocampus compared to the motor and somatosensory cortex. In 6 months old PS19 model of tauopathy, synaptic and extrasynaptic distributions are disrupted in the hippocampus but not in the cortex. Thus, this optimized super-resolution imaging tool allows us to observe synaptic deterioration at the onset of tauopathy before apparent neurodegeneration.
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Affiliation(s)
- Rohit M. Vaidya
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Jiahao Zhang
- Dept. of Physics, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Duncan Nall
- Dept. of Physics, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Yongjae Lee
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Donghan Ma
- Weldon School of Biomedical Engineering, Purdue University; West Lafayette, IN, 47907, USA
| | - Fang Huang
- Weldon School of Biomedical Engineering, Purdue University; West Lafayette, IN, 47907, USA
| | - Hiroshi Nonaka
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University; 615-8510, Kyoto, Japan
| | - Shigeki Kiyonaka
- Department of Biomolecular Engineering, Nagoya University; Nagoya, 464-8603, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Kyoto University; 615-8510, Kyoto, Japan
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
| | - Paul R. Selvin
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
- Dept. of Physics, University of Illinois at Urbana-Champaign; Urbana, IL, 61801, USA
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2
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Wu H, Chen X, Shen Z, Li H, Liang S, Lu Y, Zhang M. Phosphorylation-dependent membraneless organelle fusion and fission illustrated by postsynaptic density assemblies. Mol Cell 2024; 84:309-326.e7. [PMID: 38096828 DOI: 10.1016/j.molcel.2023.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 09/10/2023] [Accepted: 11/13/2023] [Indexed: 01/21/2024]
Abstract
Membraneless organelles formed by phase separation of proteins and nucleic acids play diverse cellular functions. Whether and, if yes, how membraneless organelles in ways analogous to membrane-based organelles also undergo regulated fusion and fission is unknown. Here, using a partially reconstituted mammalian postsynaptic density (PSD) condensate as a paradigm, we show that membraneless organelles can undergo phosphorylation-dependent fusion and fission. Without phosphorylation of the SAPAP guanylate kinase domain-binding repeats, the upper and lower layers of PSD protein mixtures form two immiscible sub-compartments in a phase-in-phase organization. Phosphorylation of SAPAP leads to fusion of the two sub-compartments into one condensate accompanied with an increased Stargazin density in the condensate. Dephosphorylation of SAPAP can reverse this event. Preventing SAPAP phosphorylation in vivo leads to increased separation of proteins from the lower and upper layers of PSD sub-compartments. Thus, analogous to membrane-based organelles, membraneless organelles can also undergo regulated fusion and fission.
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Affiliation(s)
- Haowei Wu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xudong Chen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Zeyu Shen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hao Li
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shiqi Liang
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Youming Lu
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mingjie Zhang
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518036, China; School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
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Joy MSH, Nall DL, Emon B, Lee KY, Barishman A, Ahmed M, Rahman S, Selvin PR, Saif MTA. Synapses without tension fail to fire in an in vitro network of hippocampal neurons. Proc Natl Acad Sci U S A 2023; 120:e2311995120. [PMID: 38113266 PMCID: PMC10756289 DOI: 10.1073/pnas.2311995120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/02/2023] [Indexed: 12/21/2023] Open
Abstract
Neurons in the brain communicate with each other at their synapses. It has long been understood that this communication occurs through biochemical processes. Here, we reveal that mechanical tension in neurons is essential for communication. Using in vitro rat hippocampal neurons, we find that 1) neurons become tout/tensed after forming synapses resulting in a contractile neural network, and 2) without this contractility, neurons fail to fire. To measure time evolution of network contractility in 3D (not 2D) extracellular matrix, we developed an ultrasensitive force sensor with 1 nN resolution. We employed Multi-Electrode Array and iGluSnFR, a glutamate sensor, to quantify neuronal firing at the network and at the single synapse scale, respectively. When neuron contractility is relaxed, both techniques show significantly reduced firing. Firing resumes when contractility is restored. This finding highlights the essential contribution of neural contractility in fundamental brain functions and has implications for our understanding of neural physiology.
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Affiliation(s)
- Md Saddam Hossain Joy
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Duncan L. Nall
- Department of Physics and Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Bashar Emon
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Ki Yun Lee
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Alexandra Barishman
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Movviz Ahmed
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Saeedur Rahman
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Paul R. Selvin
- Department of Physics and Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - M. Taher A. Saif
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL61801
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Li H, Le L, Marrero M, David-Bercholz J, Caceres AI, Lim C, Chiang W, Majewska AK, Terrando N, Gelbard HA. Neutrophilia with damage to the blood-brain barrier and neurovascular unit following acute lung injury. RESEARCH SQUARE 2023:rs.3.rs-3459515. [PMID: 37961257 PMCID: PMC10635322 DOI: 10.21203/rs.3.rs-3459515/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Links between acute lung injury (ALI), infectious disease, and neurological outcomes have been frequently discussed over the past few years, especially due to the COVID-19 pandemic. Yet, much of the cross-communication between organs, particularly the lung and the brain, has been understudied. Here, we have focused on the role of neutrophils in driving changes to the brain endothelium with ensuing microglial activation and neuronal loss in a model of ALI. Methods We have applied a three-dose paradigm of 10μg/40μl intranasal lipopolysaccharide (LPS) to induce neutrophilia accompanied by proteinaceous exudate in bronchoalveolar lavage fluid (BALF) in adult C57BL/6 mice. Brain endothelial markers, microglial activation, and neuronal cytoarchitecture were evaluated 24hr after the last intranasal dose of LPS or saline. C57BL/6-Ly6g(tm2621(Cre-tdTomato)Arte (Catchup mice) were used to measure neutrophil and blood-brain barrier permeability following LPS exposure with intravital 2-photon imaging. Results Three doses of intranasal LPS induced robust neutrophilia accompanied by proteinaceous exudate in BALF. ALI triggered central nervous system pathology as highlighted by robust activation of the cerebrovascular endothelium (VCAM1, CD31), accumulation of plasma protein (fibrinogen), microglial activation (IBA1, CD68), and decreased expression of proteins associated with postsynaptic terminals (PSD-95) in the hippocampal stratum lacunosum moleculare, a relay station between the entorhinal cortex and CA1 of the hippocampus. 2-photon imaging of Catchup mice revealed neutrophil homing to the cerebral endothelium in the blood-brain barrier and neutrophil extravasation from cerebral vasculature 24hr after the last intranasal treatment. Conclusions Overall, these data demonstrate ensuing brain pathology resulting from ALI, highlighting a key role for neutrophils in driving brain endothelial changes and subsequent neuroinflammation. This paradigm may have a considerable translational impact on understanding how infectious disease with ALI can lead to neurodegeneration, particularly in the elderly.
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Affiliation(s)
- Herman Li
- Center for Neurotherapeutics Discovery, University of Rochester Medical Center, Rochester, NY United States
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | - Linh Le
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
| | - Mariah Marrero
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | | | - Ana I Caceres
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Claire Lim
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
| | - Wesley Chiang
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY United States
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | - Niccolò Terrando
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Harris A Gelbard
- Center for Neurotherapeutics Discovery, University of Rochester Medical Center, Rochester, NY United States
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
- Department of Immmunology, Microbiology, and Virology, University of Rochester Medical Center, Rochester, NY United States
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY United States
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5
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Li H, Le L, Marrero M, David-Bercholz J, Caceres AI, Lim C, Chiang W, Majewska AK, Terrando N, Gelbard HA. Neutrophilia with damage to the blood-brain barrier and neurovascular unit following acute lung injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562508. [PMID: 37905036 PMCID: PMC10614777 DOI: 10.1101/2023.10.16.562508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Background Links between acute lung injury (ALI), infectious disease, and neurological outcomes have been frequently discussed over the past few years, especially due to the COVID-19 pandemic. Yet, much of the cross-communication between organs, particularly the lung and the brain, has been understudied. Here, we have focused on the role of neutrophils in driving changes to the brain endothelium with ensuing microglial activation and neuronal loss in a model of ALI. Methods We have applied a three-dose paradigm of 10μg/40μl intranasal lipopolysaccharide (LPS) to induce neutrophilia accompanied by proteinaceous exudate in bronchoalveolar lavage fluid (BALF) in adult C57BL/6 mice. Brain endothelial markers, microglial activation, and neuronal cytoarchitecture were evaluated 24hr after the last intranasal dose of LPS or saline. C57BL/6-Ly6g(tm2621(Cre-tdTomato)Arte (Catchup mice) were used to measure neutrophil and blood-brain barrier permeability following LPS exposure with intravital 2-photon imaging. Results Three doses of intranasal LPS induced robust neutrophilia accompanied by proteinaceous exudate in BALF. ALI triggered central nervous system pathology as highlighted by robust activation of the cerebrovascular endothelium (VCAM1, CD31), accumulation of plasma protein (fibrinogen), microglial activation (IBA1, CD68), and decreased expression of proteins associated with postsynaptic terminals (PSD-95) in the hippocampal stratum lacunosum moleculare, a relay station between the entorhinal cortex and CA1 of the hippocampus. 2-photon imaging of Catchup mice revealed neutrophil homing to the cerebral endothelium in the blood-brain barrier and neutrophil extravasation from cerebral vasculature 24hr after the last intranasal treatment. Conclusions Overall, these data demonstrate ensuing brain pathology resulting from ALI, highlighting a key role for neutrophils in driving brain endothelial changes and subsequent neuroinflammation. This paradigm may have a considerable translational impact on understanding how infectious disease with ALI can lead to neurodegeneration, particularly in the elderly.
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Affiliation(s)
- Herman Li
- Center for Neurotherapeutics Discovery, University of Rochester Medical Center, Rochester, NY United States
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | - Linh Le
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
| | - Mariah Marrero
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | | | - Ana I Caceres
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
| | - Claire Lim
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
| | - Wesley Chiang
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY United States
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
| | - Niccolò Terrando
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, United States
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
- Department of Immunology, Duke University Medical Center, Durham, NC, United States
| | - Harris A Gelbard
- Center for Neurotherapeutics Discovery, University of Rochester Medical Center, Rochester, NY United States
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY United States
- Department of Neurology, University of Rochester Medical Center, Rochester, NY United States
- Department of Immmunology, Microbiology, and Virology, University of Rochester Medical Center, Rochester, NY United States
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY United States
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6
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Eilts J, Reinhard S, Michetschläger N, Werner C, Sauer M. Enhanced synaptic protein visualization by multicolor super-resolution expansion microscopy. NEUROPHOTONICS 2023; 10:044412. [PMID: 37886043 PMCID: PMC10599331 DOI: 10.1117/1.nph.10.4.044412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/28/2023]
Abstract
Significance Understanding the organization of biomolecules into complexes and their dynamics is crucial for comprehending cellular functions and dysfunctions, particularly in neuronal networks connected by synapses. In the last two decades, various powerful super-resolution (SR) microscopy techniques have been developed that produced stunning images of synapses and their molecular organization. However, current SR microscopy methods do not permit multicolor fluorescence imaging with 20 to 30 nm spatial resolution. Aim We developed a method that enables 4-color fluorescence imaging of synaptic proteins in neurons with 20 to 30 nm lateral resolution. Approach We used post-expansion immunolabeling of eightfold expanded hippocampal neurons in combination with Airyscan and structured illumination microscopy (SIM). Results We demonstrate that post-expansion immunolabeling of approximately eightfold expanded hippocampal neurons enables efficient labeling of synaptic proteins in crowded compartments with minimal linkage error and enables in combination with Airyscan and SIM four-color three-dimensional fluorescence imaging with 20 to 30 nm lateral resolution. Using immunolabeling of Synaptobrevin 2 as an efficient marker of the vesicle pool allowed us to identify individual synaptic vesicles colocalized with Rab3-interacting molecule 1 and 2 (RIM1/2), a marker of pre-synaptic fusion sites. Conclusions Our optimized expansion microscopy approach improves the visualization and location of pre- and post-synaptic proteins and can thus provide invaluable insights into the spatial organization of proteins at synapses.
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Affiliation(s)
- Janna Eilts
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Sebastian Reinhard
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Nikolas Michetschläger
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Christian Werner
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Markus Sauer
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
- University of Würzburg, Rudolf Virchow Center, Research Center for Integrative and Translational Bioimaging, Würzburg, Germany
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Sha MFR, Koga Y, Murata Y, Taniguchi M, Yamaguchi M. Learning-dependent structural plasticity of intracortical and sensory connections to functional domains of the olfactory tubercle. Front Neurosci 2023; 17:1247375. [PMID: 37680965 PMCID: PMC10480507 DOI: 10.3389/fnins.2023.1247375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023] Open
Abstract
The olfactory tubercle (OT), which is a component of the olfactory cortex and ventral striatum, has functional domains that play a role in odor-guided motivated behaviors. Learning odor-guided attractive and aversive behavior activates the anteromedial (am) and lateral (l) domains of the OT, respectively. However, the mechanism driving learning-dependent activation of specific OT domains remains unknown. We hypothesized that the neuronal connectivity of OT domains is plastically altered through olfactory experience. To examine the plastic potential of synaptic connections to OT domains, we optogenetically stimulated intracortical inputs from the piriform cortex or sensory inputs from the olfactory bulb to the OT in mice in association with a food reward for attractive learning and electrical foot shock for aversive learning. For both intracortical and sensory connections, axon boutons that terminated in the OT domains were larger in the amOT than in the lOT for mice exhibiting attractive learning and larger in the lOT than in the amOT for mice exhibiting aversive learning. These results indicate that both intracortical and sensory connections to the OT domains have learning-dependent plastic potential, suggesting that this plasticity underlies learning-dependent activation of specific OT domains and the acquisition of appropriate motivated behaviors.
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Affiliation(s)
| | | | | | | | - Masahiro Yamaguchi
- Department of Physiology, Kochi Medical School, Kochi University, Kochi, Japan
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Krüssel S, Deb I, Son S, Ewall G, Chang M, Lee HK, do Heo W, Kwon HB. Exuberant de novo dendritic spine growth in mature neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.550095. [PMID: 37546796 PMCID: PMC10401948 DOI: 10.1101/2023.07.21.550095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Dendritic spines are structural correlates of excitatory synapses maintaining stable synaptic communications. However, this strong spine-synapse relationship was mainly characterized in excitatory pyramidal neurons (PyNs), raising a possibility that inferring synaptic density from dendritic spine number may not be universally applied to all neuronal types. Here we found that the ectopic expression of H-Ras increased dendritic spine numbers regardless of cortical cell types such as layer 2/3 pyramidal neurons (PyNs), parvalbumin (PV)- and vasoactive intestinal peptide (VIP)-positive interneurons (INs) in the primary motor cortex (M1). The probability of detecting dendritic spines was positively correlated with the magnitude of H-Ras activity, suggesting elevated local H-Ras activity is involved in the process of dendritic spine formation. H-Ras overexpression caused high spine turnover rate via adding more spines rather than eliminating them. Two-photon photolysis of glutamate triggered de novo dendritic spine formation in mature neurons, suggesting H-Ras induced spine formation is not restricted to the early development. In PyNs and PV-INs, but not VIP-INs, we observed a shift in average spine neck length towards longer filopodia-like phenotypes. The portion of dendritic spines lacking key excitatory synaptic proteins were significantly increased in H-Ras transfected neurons, suggesting that these increased spines have other distinct functions. High spine density caused by H-Ras did not result in change in the frequency or the amplitude of miniature excitatory postsynaptic currents (mEPSCs). Thus, our results propose that dendritic spines possess more multifaceted functions beyond the morphological proxy of excitatory synapse.
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Affiliation(s)
- Sarah Krüssel
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ishana Deb
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Seungkyu Son
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Gabrielle Ewall
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Minhyeok Chang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hey-Kyoung Lee
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Won do Heo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Hyung-Bae Kwon
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Demuth L, Ohm M, Michaelsen-Preusse K, Schulze K, Riese P, Guzmán CA, Korte M, Hosseini S. Influenza vaccine is able to prevent neuroinflammation triggered by H7N7 IAV infection. Front Pharmacol 2023; 14:1142639. [PMID: 37063291 PMCID: PMC10090407 DOI: 10.3389/fphar.2023.1142639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/21/2023] [Indexed: 03/31/2023] Open
Abstract
Influenza A virus (IAV) subtypes are a major cause of illness and mortality worldwide and pose a threat to human health. Although IAV infection is considered a self-limiting respiratory syndrome, an expanded spectrum of cerebral manifestations has been reported following IAV infection. Neurotropic IAVs, such as the H7N7 subtype, are capable of invading the central nervous system (CNS) and replicating in brain cells, resulting in microglia-induced neuroinflammation. Microglial cells, the brain’s resident immune cells, are instrumental in the inflammatory response to viral infection. While activation of microglia is important to initially contain the virus, excessive activation of these cells leads to neuronal damage. Previous studies have shown that acute and even long-term IAV-induced neuroinflammation leads to CNS damage. Therefore, the search for possible preventive or therapeutic strategies is of great importance. In this study, we investigated the potential effect of vaccination against acute neuroinflammation induced by H7N7 infection and subsequent neuronal damage in the hippocampus, a particularly vulnerable brain region, comparing young and aged mice. Immunosenescence is one of the striking pathophysiological changes during mammalian aging that leads to “inflammaging” and critically limits the protection by vaccines in the elderly. The results suggest that formalin-inactivated H7N7 vaccine has a preventive effect against the inflammatory responses in the periphery and also in the CNS after H7N7 infection. Cytokine and chemokine levels, increased microglial density, and cell volume after H7N7 infection were all attenuated by vaccination. Further structural analysis of microglial cells also revealed a change in branching complexity after H7N7 infection, most likely reflecting the neuroprotective effect of the vaccination. In addition, synapse loss was prevented in vaccinated mice. Remarkably, engulfment of post-synaptic compartments by microglia can be proposed as the underlying mechanism for spine loss triggered by H7N7 infection, which was partially modulated by vaccination. Although young mice showed better protection against neuroinflammation and the resulting deleterious neuronal effects upon vaccination, a beneficial role of the vaccine was also observed in the brains of older mice. Therefore, vaccination can be proposed as an important strategy to prevent neurological sequelae of H7N7 infection.
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Affiliation(s)
- Luisa Demuth
- Department of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Melanie Ohm
- Department of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Kristin Michaelsen-Preusse
- Department of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Kai Schulze
- Helmholtz Centre for Infection Research, Department of Vaccinology and Applied Microbiology, Braunschweig, Germany
| | - Peggy Riese
- Helmholtz Centre for Infection Research, Department of Vaccinology and Applied Microbiology, Braunschweig, Germany
| | - Carlos A. Guzmán
- Helmholtz Centre for Infection Research, Department of Vaccinology and Applied Microbiology, Braunschweig, Germany
| | - Martin Korte
- Department of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany
| | - Shirin Hosseini
- Department of Cellular Neurobiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany
- *Correspondence: Shirin Hosseini,
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mGluR5 is transiently confined in perisynaptic nanodomains to shape synaptic function. Nat Commun 2023; 14:244. [PMID: 36646691 PMCID: PMC9842668 DOI: 10.1038/s41467-022-35680-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 12/19/2022] [Indexed: 01/18/2023] Open
Abstract
The unique perisynaptic distribution of postsynaptic metabotropic glutamate receptors (mGluRs) at excitatory synapses is predicted to directly shape synaptic function, but mechanistic insight into how this distribution is regulated and impacts synaptic signaling is lacking. We used live-cell and super-resolution imaging approaches, and developed molecular tools to resolve and acutely manipulate the dynamic nanoscale distribution of mGluR5. Here we show that mGluR5 is dynamically organized in perisynaptic nanodomains that localize close to, but not in the synapse. The C-terminal domain of mGluR5 critically controlled perisynaptic confinement and prevented synaptic entry. We developed an inducible interaction system to overcome synaptic exclusion of mGluR5 and investigate the impact on synaptic function. We found that mGluR5 recruitment to the synapse acutely increased synaptic calcium responses. Altogether, we propose that transient confinement of mGluR5 in perisynaptic nanodomains allows flexible modulation of synaptic function.
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11
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Nair JD, Braksator E, Yucel BP, Fletcher-Jones A, Seager R, Mellor JR, Bashir ZI, Wilkinson KA, Henley JM. Sustained postsynaptic kainate receptor activation downregulates AMPA receptor surface expression and induces hippocampal LTD. iScience 2021; 24:103029. [PMID: 34553130 PMCID: PMC8441151 DOI: 10.1016/j.isci.2021.103029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 07/27/2021] [Accepted: 08/20/2021] [Indexed: 01/21/2023] Open
Abstract
It is well established that long-term depression (LTD) can be initiated by either NMDA or mGluR activation. Here we report that sustained activation of GluK2 subunit-containing kainate receptors (KARs) leads to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) endocytosis and induces LTD of AMPARs (KAR-LTDAMPAR) in hippocampal neurons. The KAR-evoked loss of surface AMPARs is blocked by the ionotropic KAR inhibitor UBP 310 indicating that KAR-LTDAMPAR requires KAR channel activity. Interestingly, however, blockade of PKC or PKA also reduces GluA2 surface expression and occludes the effect of KAR activation. In acute hippocampal slices, kainate application caused a significant loss of GluA2-containing AMPARs from synapses and long-lasting depression of AMPAR excitatory postsynaptic currents in CA1. These data, together with our previously reported KAR-LTPAMPAR, demonstrate that KARs can bidirectionally regulate synaptic AMPARs and synaptic plasticity via different signaling pathways.
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Affiliation(s)
- Jithin D Nair
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Ellen Braksator
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Busra P Yucel
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Alexandra Fletcher-Jones
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Richard Seager
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Zafar I Bashir
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kevin A Wilkinson
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jeremy M Henley
- Centre for Synaptic Plasticity, School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK.,Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
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12
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mGluR1 signaling in cerebellar Purkinje cells: Subcellular organization and involvement in cerebellar function and disease. Neuropharmacology 2021; 194:108629. [PMID: 34089728 DOI: 10.1016/j.neuropharm.2021.108629] [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: 03/05/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/20/2022]
Abstract
The cerebellum is essential for the control, coordination, and learning of movements, and for certain aspects of cognitive function. Purkinje cells are the sole output neurons in the cerebellar cortex and therefore play crucial roles in the diverse functions of the cerebellum. The type 1 metabotropic glutamate receptor (mGluR1) is prominently enriched in Purkinje cells and triggers downstream signaling pathways that are required for functional and structural plasticity, and for synaptic responses. To understand how mGluR1 contributes to cerebellar functions, it is important to consider not only the operational properties of this receptor, but also its spatial organization and the molecular interactions that enable its proper functioning. In this review, we highlight how mGluR1 and its related signaling molecules are organized into tightly coupled microdomains to fulfill physiological functions. We also describe emerging evidence that altered mGluR1 signaling in Purkinje cells underlies cerebellar dysfunction in ataxias of human patients and mouse models.
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13
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Tao-Cheng JH, Crocker V, Moreira SL, Azzam R. Optimization of protocols for pre-embedding immunogold electron microscopy of neurons in cell cultures and brains. Mol Brain 2021; 14:86. [PMID: 34082785 PMCID: PMC8173732 DOI: 10.1186/s13041-021-00799-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/27/2021] [Indexed: 02/08/2023] Open
Abstract
Immunogold labeling allows localization of proteins at the electron microscopy (EM) level of resolution, and quantification of signals. The present paper summarizes methodological issues and experiences gained from studies on the distribution of synaptic and other neuron-specific proteins in cell cultures and brain tissues via a pre-embedding method. An optimal protocol includes careful determination of a fixation condition for any particular antibody, a well-planned tissue processing procedure, and a strict evaluation of the credibility of the labeling. Here, tips and caveats on different steps of the sample preparation protocol are illustrated with examples. A good starting condition for EM-compatible fixation and permeabilization is 4% paraformaldehyde in PBS for 30 min at room temperature, followed by 30 min incubation with 0.1% saponin. An optimal condition can then be readjusted for each particular antibody. Each lot of the secondary antibody (conjugated with a 1.4 nm small gold particle) needs to be evaluated against known standards for labeling efficiency. Silver enhancement is required to make the small gold visible, and quality of the silver-enhanced signals can be affected by subsequent steps of osmium tetroxide treatment, uranyl acetate en bloc staining, and by detergent or ethanol used to clean the diamond knife for cutting thin sections. Most importantly, verification of signals requires understanding of the protein of interest in order to validate for correct localization of antibodies at expected epitopes on particular organelles, and quantification of signals needs to take into consideration the penetration gradient of reagents and clumping of secondary antibodies.
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Affiliation(s)
- Jung-Hwa Tao-Cheng
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Virginia Crocker
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sandra Lara Moreira
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Rita Azzam
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
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14
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Suzuki T, Terada N, Higashiyama S, Kametani K, Shirai Y, Honda M, Kai T, Li W, Tabuchi K. Non-microtubule tubulin-based backbone and subordinate components of postsynaptic density lattices. Life Sci Alliance 2021; 4:4/7/e202000945. [PMID: 34006534 PMCID: PMC8326785 DOI: 10.26508/lsa.202000945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 12/28/2022] Open
Abstract
This study proposes a postsynaptic density (PSD) lattice model comprising a non-microtubule tubulin-based backbone structure and its associated proteins, including various PSD scaffold/adaptor proteins and other PSD proteins. A purification protocol was developed to identify and analyze the component proteins of a postsynaptic density (PSD) lattice, a core structure of the PSD of excitatory synapses in the central nervous system. “Enriched”- and “lean”-type PSD lattices were purified by synaptic plasma membrane treatment to identify the protein components by comprehensive shotgun mass spectrometry and group them into minimum essential cytoskeleton (MEC) and non-MEC components. Tubulin was found to be a major component of the MEC, with non-microtubule tubulin widely distributed on the purified PSD lattice. The presence of tubulin in and around PSDs was verified by post-embedding immunogold labeling EM of cerebral cortex. Non-MEC proteins included various typical scaffold/adaptor PSD proteins and other class PSD proteins. Thus, this study provides a new PSD lattice model consisting of non-microtubule tubulin-based backbone and various non-MEC proteins. Our findings suggest that tubulin is a key component constructing the backbone and that the associated components are essential for the versatile functions of the PSD.
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Affiliation(s)
- Tatsuo Suzuki
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Nobuo Terada
- Health Science Division, Department of Medical Sciences, Graduate School of Medicine, Science and Technology, Shinshu University, Matsumoto, Nagano, Japan
| | - Shigeki Higashiyama
- Department of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, To-on, Ehime, Japan
| | - Kiyokazu Kametani
- Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan
| | - Mamoru Honda
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Tsutomu Kai
- Bioscience Group, Center for Precision Medicine Supports, Pharmaceuticals and Life Sciences Division, Shimadzu Techno-Research, INC, Kyoto, Japan
| | - Weidong Li
- Bio-X Institutes, Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Shanghai Jiao Tong University, Shanghai, China.,Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Shinshu University Academic Assembly, Institute of Medicine, Shinshu University Academic Assembly, Matsumoto, Japan.,Department of Biological Sciences for Intractable Neurological Diseases, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research Shinshu University, Matsumoto, Japan
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15
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Janiri D, Kotzalidis GD, di Luzio M, Giuseppin G, Simonetti A, Janiri L, Sani G. Genetic neuroimaging of bipolar disorder: a systematic 2017-2020 update. Psychiatr Genet 2021; 31:50-64. [PMID: 33492063 DOI: 10.1097/ypg.0000000000000274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
There is evidence of genetic polymorphism influences on brain structure and function, genetic risk in bipolar disorder (BD), and neuroimaging correlates of BD. How genetic influences related to BD could be reflected on brain changes in BD has been efficiently reviewed in a 2017 systematic review. We aimed to confirm and extend these findings through a Preferred Reporting Items for Systematic reviews and Meta-Analyses-based systematic review. Our study allowed us to conclude that there is no replicated finding in the timeframe considered. We were also unable to further confirm prior results of the BDNF gene polymorphisms to affect brain structure and function in BD. The most consistent finding is an influence of the CACNA1C rs1006737 polymorphism in brain connectivity and grey matter structure and function. There was a tendency of undersized studies to obtain positive results and large, genome-wide polygenic risk studies to find negative results in BD. The neuroimaging genetics in BD field is rapidly expanding.
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Affiliation(s)
- Delfina Janiri
- Department of Neurology, Fondazione Policlinico Universitario Agostino Gemelli IRCCS
- Department of Psychiatry and Neurology, Sapienza University of Rome
| | - Georgios D Kotzalidis
- NESMOS Department, Sant'Andrea University Hospital, School of Medicine and Psychology, Sapienza University
| | - Michelangelo di Luzio
- Department of Neuroscience, Section of Psychiatry, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giulia Giuseppin
- Department of Neuroscience, Section of Psychiatry, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessio Simonetti
- Department of Psychiatry and Neurology, Sapienza University of Rome
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas, USA
| | - Luigi Janiri
- Department of Neuroscience, Section of Psychiatry, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Psychiatry, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Gabriele Sani
- Department of Neuroscience, Section of Psychiatry, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Psychiatry, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
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16
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Lachgar M, Morín M, Villamar M, del Castillo I, Moreno-Pelayo MÁ. A Novel Truncating Mutation in HOMER2 Causes Nonsyndromic Progressive DFNA68 Hearing Loss in a Spanish Family. Genes (Basel) 2021; 12:411. [PMID: 33809266 PMCID: PMC8001007 DOI: 10.3390/genes12030411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 12/02/2022] Open
Abstract
Nonsyndromic hereditary hearing loss is a common sensory defect in humans that is clinically and genetically highly heterogeneous. So far, 122 genes have been associated with this disorder and 50 of them have been linked to autosomal dominant (DFNA) forms like DFNA68, a rare subtype of hearing impairment caused by disruption of a stereociliary scaffolding protein (HOMER2) that is essential for normal hearing in humans and mice. In this study, we report a novel HOMER2 variant (c.832_836delCCTCA) identified in a Spanish family by using a custom NGS targeted gene panel (OTO-NGS-v2). This frameshift mutation produces a premature stop codon that may lead in the absence of NMD to a shorter variant (p.Pro278Alafs*10) that truncates HOMER2 at the CDC42 binding domain (CBD) of the coiled-coil structure, a region that is essential for protein multimerization and HOMER2-CDC42 interaction. c.832_836delCCTCA mutation is placed close to the previously identified c.840_840dup mutation found in a Chinese family that truncates the protein (p.Met281Hisfs*9) at the CBD. Functional assessment of the Chinese mutant revealed decreased protein stability, reduced ability to multimerize, and altered distribution pattern in transfected cells when compared with wild-type HOMER2. Interestingly, the Spanish and Chinese frameshift mutations might exert a similar effect at the protein level, leading to truncated mutants with the same Ct aberrant protein tail, thus suggesting that they can share a common mechanism of pathogenesis. Indeed, age-matched patients in both families display quite similar hearing loss phenotypes consisting of early-onset, moderate-to-profound progressive hearing loss. In summary, we have identified the third variant in HOMER2, which is the first one identified in the Spanish population, thus contributing to expanding the mutational spectrum of this gene in other populations, and also to clarifying the genotype-phenotype correlations of DFNA68 hearing loss.
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Affiliation(s)
- María Lachgar
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar km 9.100, 28034 Madrid, Spain; (M.L.); (M.M.); (M.V.); (I.d.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
| | - Matías Morín
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar km 9.100, 28034 Madrid, Spain; (M.L.); (M.M.); (M.V.); (I.d.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
| | - Manuela Villamar
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar km 9.100, 28034 Madrid, Spain; (M.L.); (M.M.); (M.V.); (I.d.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
| | - Ignacio del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar km 9.100, 28034 Madrid, Spain; (M.L.); (M.M.); (M.V.); (I.d.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
| | - Miguel Ángel Moreno-Pelayo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar km 9.100, 28034 Madrid, Spain; (M.L.); (M.M.); (M.V.); (I.d.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
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17
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Jansch C, Ziegler GC, Forero A, Gredy S, Wäldchen S, Vitale MR, Svirin E, Zöller JEM, Waider J, Günther K, Edenhofer F, Sauer M, Wischmeyer E, Lesch KP. Serotonin-specific neurons differentiated from human iPSCs form distinct subtypes with synaptic protein assembly. J Neural Transm (Vienna) 2021; 128:225-241. [PMID: 33560471 PMCID: PMC7914246 DOI: 10.1007/s00702-021-02303-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/10/2021] [Indexed: 02/06/2023]
Abstract
Human induced pluripotent stem cells (hiPSCs) have revolutionized the generation of experimental disease models, but the development of protocols for the differentiation of functionally active neuronal subtypes with defined specification is still in its infancy. While dysfunction of the brain serotonin (5-HT) system has been implicated in the etiology of various neuropsychiatric disorders, investigation of functional human 5-HT specific neurons in vitro has been restricted by technical limitations. We describe an efficient generation of functionally active neurons from hiPSCs displaying 5-HT specification by modification of a previously reported protocol. Furthermore, 5-HT specific neurons were characterized using high-end fluorescence imaging including super-resolution microscopy in combination with electrophysiological techniques. Differentiated hiPSCs synthesize 5-HT, express specific markers, such as tryptophan hydroxylase 2 and 5-HT transporter, and exhibit an electrophysiological signature characteristic of serotonergic neurons, with spontaneous rhythmic activities, broad action potentials and large afterhyperpolarization potentials. 5-HT specific neurons form synapses reflected by the expression of pre- and postsynaptic proteins, such as Bassoon and Homer. The distribution pattern of Bassoon, a marker of the active zone along the soma and extensions of neurons, indicates functionality via volume transmission. Among the high percentage of 5-HT specific neurons (~ 42%), a subpopulation of CDH13 + cells presumably designates dorsal raphe neurons. hiPSC-derived 5-HT specific neuronal cell cultures reflect the heterogeneous nature of dorsal and median raphe nuclei and may facilitate examining the association of serotonergic neuron subpopulations with neuropsychiatric disorders.
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Affiliation(s)
- Charline Jansch
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Georg C Ziegler
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Würzburg, Würzburg, Germany.
| | - Andrea Forero
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Sina Gredy
- Institute of Physiology, Molecular Electrophysiology, University of Würzburg, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Sina Wäldchen
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Maria Rosaria Vitale
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Evgeniy Svirin
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Johanna E M Zöller
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Department of Translational Neuroscience, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
| | - Jonas Waider
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Katharina Günther
- Department of Genomics, Stem Cell Biology and Regenerative Medicine, Institute of Molecular Biology and CMBI, Leopold-Franzens-University Innsbruck, Innsbruck, Austria
- Institute of Molecular Regenerative Medicine, SCI-TReCS, Paracelsus Medical University, Salzburg, Austria
| | - Frank Edenhofer
- Department of Genomics, Stem Cell Biology and Regenerative Medicine, Institute of Molecular Biology and CMBI, Leopold-Franzens-University Innsbruck, Innsbruck, Austria
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Erhard Wischmeyer
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Institute of Physiology, Molecular Electrophysiology, University of Würzburg, Würzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia.
- Department of Translational Neuroscience, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands.
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18
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Volumetric live cell imaging with three-dimensional parallelized RESOLFT microscopy. Nat Biotechnol 2021; 39:609-618. [PMID: 33432197 DOI: 10.1038/s41587-020-00779-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/19/2020] [Indexed: 11/09/2022]
Abstract
Elucidating the volumetric architecture of organelles and molecules inside cells requires microscopy methods with a sufficiently high spatial resolution in all three dimensions. Current methods are limited by insufficient resolving power along the optical axis, long recording times and photobleaching when applied to live cell imaging. Here, we present a 3D, parallelized, reversible, saturable/switchable optical fluorescence transition (3D pRESOLFT) microscope capable of delivering sub-80-nm 3D resolution in whole living cells. We achieved rapid (1-2 Hz) acquisition of large fields of view (~40 × 40 µm2) by highly parallelized image acquisition with an interference pattern that creates an array of 3D-confined and equally spaced intensity minima. This allowed us to reversibly turn switchable fluorescent proteins to dark states, leading to a targeted 3D confinement of fluorescence. We visualized the 3D organization and dynamics of organelles in living cells and volumetric structural alterations of synapses during plasticity in cultured hippocampal neurons.
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19
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Wiesner T, Bilodeau A, Bernatchez R, Deschênes A, Raulier B, De Koninck P, Lavoie-Cardinal F. Activity-Dependent Remodeling of Synaptic Protein Organization Revealed by High Throughput Analysis of STED Nanoscopy Images. Front Neural Circuits 2020; 14:57. [PMID: 33177994 PMCID: PMC7594516 DOI: 10.3389/fncir.2020.00057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 07/29/2020] [Indexed: 01/03/2023] Open
Abstract
The organization of proteins in the apposed nanodomains of pre- and postsynaptic compartments is thought to play a pivotal role in synaptic strength and plasticity. As such, the alignment between pre- and postsynaptic proteins may regulate, for example, the rate of presynaptic release or the strength of postsynaptic signaling. However, the analysis of these structures has mainly been restricted to subsets of synapses, providing a limited view of the diversity of synaptic protein cluster remodeling during synaptic plasticity. To characterize changes in the organization of synaptic nanodomains during synaptic plasticity over a large population of synapses, we combined STimulated Emission Depletion (STED) nanoscopy with a Python-based statistical object distance analysis (pySODA), in dissociated cultured hippocampal circuits exposed to treatments driving different forms of synaptic plasticity. The nanoscale organization, characterized in terms of coupling properties, of presynaptic (Bassoon, RIM1/2) and postsynaptic (PSD95, Homer1c) scaffold proteins was differently altered in response to plasticity-inducing stimuli. For the Bassoon - PSD95 pair, treatments driving synaptic potentiation caused an increase in their coupling probability, whereas a stimulus driving synaptic depression had an opposite effect. To enrich the characterization of the synaptic cluster remodeling at the population level, we applied unsupervised machine learning approaches to include selected morphological features into a multidimensional analysis. This combined analysis revealed a large diversity of synaptic protein cluster subtypes exhibiting differential activity-dependent remodeling, yet with common features depending on the expected direction of plasticity. The expanded palette of synaptic features revealed by our unbiased approach should provide a basis to further explore the widely diverse molecular mechanisms of synaptic plasticity.
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Affiliation(s)
| | | | | | | | | | - Paul De Koninck
- CERVO Brain Research Centre, Québec, QC, Canada.,Department of Biochemistry, Microbiology and Bioinformatics, Université Laval, Québec, QC, Canada
| | - Flavie Lavoie-Cardinal
- CERVO Brain Research Centre, Québec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
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20
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Regional Brain Recovery from Acute Synaptic Injury in Simian Immunodeficiency Virus-Infected Rhesus Macaques Associates with Heme Oxygenase Isoform Expression. J Virol 2020; 94:JVI.01102-20. [PMID: 32669339 PMCID: PMC7495379 DOI: 10.1128/jvi.01102-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/10/2020] [Indexed: 12/21/2022] Open
Abstract
Brain injury induced by acute simian (or human) immunodeficiency virus infection may persist or spontaneously resolve in different brain regions. Identifying the host factor(s) that promotes spontaneous recovery from such injury may reveal targets for therapeutic drug strategies for promoting recovery from acute neuronal injury. The gradual recovery from such injury observed in many, but not all, brain regions in the rhesus macaque model is consistent with the possible existence of a therapeutic window of opportunity for intervening to promote recovery, even in those regions not showing spontaneous recovery. In persons living with human immunodeficiency virus infection, such neuroprotective treatments could ultimately be considered as adjuncts to the initiation of antiretroviral drug therapy. Brain injury occurs within days in simian immunodeficiency virus (SIV) or human immunodeficiency virus (HIV) infection, and some recovery may occur within weeks. Inflammation and oxidative stress associate with such injury, but what drives recovery is unknown. Chronic HIV infection associates with reduced brain frontal cortex expression of the antioxidant/anti-inflammatory enzyme heme oxygenase-1 (HO-1) and increased neuroinflammation in individuals with cognitive impairment. We hypothesized that acute regional brain injury and recovery associate with differences in regional brain HO-1 expression. Using SIV-infected rhesus macaques, we analyzed multiple brain regions through acute and chronic infection (90 days postinfection [dpi]) and quantified viral (SIV gag RNA), synaptic (PSD-95; synaptophysin), axonal (neurofilament/neurofilament light chain [NFL]), inflammatory, and antioxidant (enzymes, including heme oxygenase isoforms [HO-1, HO-2]) markers. PSD-95 was reduced in the brainstem, basal ganglia, neocortex, and cerebellum within 13 dpi, indicating acute synaptic injury throughout the brain. All areas except the brainstem recovered. Unchanged NFL was consistent with no acute axonal injury. SIV RNA expression was highest in the brainstem throughout infection, and it associated with neuroinflammation. Surprisingly, during the synaptic injury and recovery phases, HO-2, and not HO-1, progressively decreased in the brainstem. Thus, acute SIV synaptic injury occurs throughout the brain, with spontaneous recovery in regions other than the brainstem. Within the brainstem, the high SIV load and inflammation, along with reduction of HO-2, may impair recovery. In other brain regions, stable HO-2 expression, with or without increasing HO-1, may promote recovery. Our data support roles for heme oxygenase isoforms in modulating recovery from synaptic injury in SIV infection and suggest their therapeutic targeting for promoting neuronal recovery. IMPORTANCE Brain injury induced by acute simian (or human) immunodeficiency virus infection may persist or spontaneously resolve in different brain regions. Identifying the host factor(s) that promotes spontaneous recovery from such injury may reveal targets for therapeutic drug strategies for promoting recovery from acute neuronal injury. The gradual recovery from such injury observed in many, but not all, brain regions in the rhesus macaque model is consistent with the possible existence of a therapeutic window of opportunity for intervening to promote recovery, even in those regions not showing spontaneous recovery. In persons living with human immunodeficiency virus infection, such neuroprotective treatments could ultimately be considered as adjuncts to the initiation of antiretroviral drug therapy.
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Sograte-Idrissi S, Schlichthaerle T, Duque-Afonso CJ, Alevra M, Strauss S, Moser T, Jungmann R, Rizzoli SO, Opazo F. Circumvention of common labelling artefacts using secondary nanobodies. NANOSCALE 2020; 12:10226-10239. [PMID: 32356544 DOI: 10.1039/d0nr00227e] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A standard procedure to study cellular elements is via immunostaining followed by optical imaging. This methodology typically requires target-specific primary antibodies (1.Abs), which are revealed by secondary antibodies (2.Abs). Unfortunately, the antibody bivalency, polyclonality, and large size can result in a series of artifacts. Alternatively, small, monovalent probes, such as single-domain antibodies (nanobodies) have been suggested to minimize these limitations. The discovery and validation of nanobodies against specific targets are challenging, thus only a minimal amount of them are currently available. Here, we used STED, DNA-PAINT, and light-sheet microscopy, to demonstrate that secondary nanobodies (1) increase localization accuracy compared to 2.Abs; (2) allow direct pre-mixing with 1.Abs before staining, reducing experimental time, and enabling the use of multiple 1.Abs from the same species; (3) penetrate thick tissues more efficiently; and (4) avoid probe-induced clustering of target molecules observed with conventional 2.Abs in living or poorly fixed samples. Altogether, we show how secondary nanobodies are a valuable alternative to 2.Abs.
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Affiliation(s)
- Shama Sograte-Idrissi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany. and Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany and International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Thomas Schlichthaerle
- Faculty of Physics and Center for Nanoscience, LMU Munich, 80539, Munich, Germany and Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Carlos J Duque-Afonso
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany and Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany and Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany and University of Göttingen, 37075, Göttingen, Germany
| | - Mihai Alevra
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany.
| | - Sebastian Strauss
- Faculty of Physics and Center for Nanoscience, LMU Munich, 80539, Munich, Germany and Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37075 Göttingen, Germany and Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany and Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany and University of Göttingen, 37075, Göttingen, Germany
| | - Ralf Jungmann
- Faculty of Physics and Center for Nanoscience, LMU Munich, 80539, Munich, Germany and Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Silvio O Rizzoli
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany. and Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany and Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany. and Center for Biostructural Imaging of Neurodegeneration (BIN), University of Göttingen Medical Center, 37075 Göttingen, Germany and NanoTag Biotechnologies GmbH, 37079, Göttingen, Germany
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22
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Tao-Cheng JH. Activity-dependent redistribution of CaMKII in the postsynaptic compartment of hippocampal neurons. Mol Brain 2020; 13:53. [PMID: 32238193 PMCID: PMC7110642 DOI: 10.1186/s13041-020-00594-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 03/23/2020] [Indexed: 11/10/2022] Open
Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII), an abundant protein in neurons, is involved in synaptic plasticity and learning. CaMKII associates with multiple proteins located at or near the postsynaptic density (PSD), and CaMKII is known to translocate from cytoplasm to PSD under excitatory conditions. The present study examined the laminar distribution of CaMKII at the PSD by immunogold labeling in dissociated hippocampal cultures under low calcium (EGTA or APV), control, and stimulated (depolarization with high K+ or NMDA) conditions. The patterns of CaMKII distribution are classified with particular reference to the two layers of the PSD: (1) the PSD core, a layer within ~ 30-40 nm to the postsynaptic membrane, and (2) the PSD pallium, a deeper layer beyond the PSD core, ~ 100-120 nm from the postsynaptic membrane. Under low calcium conditions, a subpopulation (40%) of synapses stood out with no CaMKII labeling at the PSD, indicating that localization of CaMKII at the PSD is sensitive to calcium levels. Under control conditions, the majority (~ 60-70%) of synapses had label for CaMKII dispersed evenly in the spine, including the PSD and the nearby cytoplasm. Upon stimulation, the majority (60-75%) of synapses had label for CaMKII concentrated at the PSD, delineating the PSD pallium from the cytoplasm. Median distance of label for CaMKII to postsynaptic membrane was higher in low calcium samples (68-77 nm), than in control (59-63 nm) and stimulated samples (49-53 nm). Thus, upon stimulation, not only more CaMKII translocated to the PSD, but they also were closer to the postsynaptic membrane. Additionally, there were two relatively infrequent labeling patterns that may represent intermediate stages of CaMKII distribution between basal and stimulated conditions: (1) one type showed label preferentially localized near the PSD core where CaMKII may be binding to NR2B, an NMDA receptor concentrated at the PSD core, and (2) the second type showed label preferentially in the PSD pallium, where CaMKII may be binding to Shank, a PSD scaffold protein located in the PSD pallium. Both of these distribution patterns may portray the initial stages of CaMKII translocation upon synaptic activation. In addition to binding to PSD proteins, the concentrated CaMKII labeling at the PSD under heightened excitatory conditions could also be formed by self-clustering of CaMKII molecules recruited to the PSD. Most importantly, these accumulated CaMKII molecules do not extend beyond the border of the PSD pallium, and are likely held in the pallium by binding to Shank under these conditions.
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Affiliation(s)
- Jung-Hwa Tao-Cheng
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
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23
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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24
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Deshpande D, Higelin J, Schoen M, Vomhof T, Boeckers TM, Demestre M, Michaelis J. Synaptic FUS Localization During Motoneuron Development and Its Accumulation in Human ALS Synapses. Front Cell Neurosci 2019; 13:256. [PMID: 31244613 PMCID: PMC6582137 DOI: 10.3389/fncel.2019.00256] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/23/2019] [Indexed: 12/21/2022] Open
Abstract
Mutations in the fused in Sarcoma (FUS) gene induce cytoplasmic FUS aggregations, contributing to the neurodegenerative disease amyotrophic lateral sclerosis (ALS) in certain cases. While FUS is mainly a nuclear protein involved in transcriptional processes with limited cytoplasmic functions, it shows an additional somatodendritic localization in neurons. In this study we analyzed the localization of FUS in motoneuron synapses, these being the most affected neurons in ALS, using super-resolution microscopy to distinguish between the pre- and postsynaptic compartments. We report a maturation-based variation of FUS localization in rodent synapses where a predominantly postsynaptic FUS was observed in the early stages of synaptic development, while in mature synapses the protein was entirely localized in the axonal terminal. Likewise, we also show that at the synapse of human motoneurons derived from induced pluripotent stem cells of a healthy control, FUS is mainly postsynaptic in the early developmental stages. In motoneurons derived from ALS patients harboring a very aggressive juvenile FUS mutation, increased synaptic accumulation of mutated FUS was observed. Moreover increased aggregation of other synaptic proteins Bassoon and Homer1 was also detected in these abnormal synapses. Having demonstrated changes in the FUS localization during synaptogenesis, a role of synaptic FUS in both dendritic and axonal cellular compartments is probable, and we propose a gain-of-toxic function due to the synaptic aggregation of mutant FUS in ALS.
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Affiliation(s)
| | - Julia Higelin
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Michael Schoen
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Thomas Vomhof
- Institute of Biophysics, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,German Center for Neurodegenerative Diseases (DZNE), Ulm Site, Ulm, Germany
| | - Maria Demestre
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
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25
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Tao-Cheng JH. Stimulation induces gradual increases in the thickness and curvature of postsynaptic density of hippocampal CA1 neurons in slice cultures. Mol Brain 2019; 12:44. [PMID: 31053145 PMCID: PMC6499976 DOI: 10.1186/s13041-019-0468-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/25/2019] [Indexed: 11/10/2022] Open
Abstract
Activity can induce structural changes in glutamatergic excitatory synapses, including increase in thickness and curvature of the postsynaptic density (PSD); these structural changes can only be documented by electron microscopy. Here in organotypic hippocampal slice cultures where experimental conditions can be easily manipulated, increases in thickness and curvature of PSDs were noticeable within 30 s of stimulation and progressed with time up to 3 min. These structural changes were reversible upon returning the samples to control medium for 5-10 min. Thus, the postsynaptic density is a very dynamic structure that undergoes rapid reorganization of its components upon stimulation, and recovery upon cessation of stimulation. The gradual increase in thickness of PSD could result from a gradual translocation of some PSD proteins to the PSD, and the increase in curvature of the PSD is likely led by postsynaptic elements.
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Affiliation(s)
- Jung-Hwa Tao-Cheng
- NINDS Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
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26
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Postsynaptic protein organization revealed by electron microscopy. Curr Opin Struct Biol 2019; 54:152-160. [PMID: 30904821 PMCID: PMC6753054 DOI: 10.1016/j.sbi.2019.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/02/2019] [Accepted: 02/18/2019] [Indexed: 11/21/2022]
Abstract
Neuronal synapses are key devices for transmitting and processing information in the nervous system. Synaptic plasticity, generally regarded as the cellular basis of learning and memory, involves changes of subcellular structures that take place at the nanoscale. High-resolution imaging methods, especially electron microscopy (EM), have allowed for quantitative analysis of such nanoscale structures in different types of synapses. In particular, the semi-ordered organization of neurotransmitter receptors and their interacting scaffolds in the postsynaptic density have been characterized for both excitatory and inhibitory synapses by studies using various EM techniques such as immuno-EM, electron tomography of high-pressure freezing and freeze-substituted samples, and cryo electron tomography. These techniques, in combination with new correlative approaches, will further facilitate our understanding of the molecular organization underlying diverse functions of neuronal synapses.
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27
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Kursula P. Shanks — multidomain molecular scaffolds of the postsynaptic density. Curr Opin Struct Biol 2019; 54:122-128. [DOI: 10.1016/j.sbi.2019.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/24/2018] [Accepted: 01/22/2019] [Indexed: 10/27/2022]
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28
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Naito R, Kassai H, Sakai Y, Schönherr S, Fukaya M, Schwarzer C, Sakagami H, Nakao K, Aiba A, Ferraguti F. New Features on the Expression and Trafficking of mGluR1 Splice Variants Exposed by Two Novel Mutant Mouse Lines. Front Mol Neurosci 2018; 11:439. [PMID: 30559646 PMCID: PMC6287019 DOI: 10.3389/fnmol.2018.00439] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/13/2018] [Indexed: 01/08/2023] Open
Abstract
Metabotropic glutamate receptors (mGluRs) couple to G-proteins to modulate slow synaptic transmission via intracellular second messengers. The first cloned mGluR, mGluR1, regulates motor coordination, synaptic plasticity and synapse elimination. mGluR1 undergoes alternative splicing giving rise to four translated variants that differ in their intracellular C-terminal domains. Our current knowledge about mGluR1 relates almost entirely to the long mGluR1α isoform, whereas little is known about the other shorter variants. To study the expression of mGluR1γ, we have generated by means of the CRISPR/Cas9 system a new knock-in (KI) mouse line in which the C-terminus of this variant carries two short tags. Using this mouse line, we could establish that mGluR1γ is either untranslated or in amounts that are undetectable in the mouse cerebellum, indicating that only mGluR1α and mGluR1β are present and active at cerebellar synapses. The trafficking and function of mGluR1 appear strongly influenced by adaptor proteins such as long Homers that bind to the C-terminus of mGluR1α. We generated a second transgenic (Tg) mouse line in which mGluR1α carries a point mutation in its Homer binding domain and studied whether disruption of this interaction influenced mGluR1 subcellular localization at cerebellar parallel fiber (PF)-Purkinje cell (PC) synapses by means of the freeze-fracture replica immunolabeling technique. These Tg animals did not show any overt behavioral phenotype, and despite the typical mGluR1 perisynaptic distribution was not significantly changed, we observed a higher probability of intrasynaptic diffusion suggesting that long Homers regulate the lateral mobility of mGluR1. We extended our ultrastructural analysis to other mouse lines in which only one mGluR1 variant was reintroduced in PC of mGluR1-knock out (KO) mice. This work revealed that mGluR1α preferentially accumulates closer to the edge of the postsynaptic density (PSD), whereas mGluR1β has a less pronounced perijunctional distribution and, in the absence of mGluR1α, its trafficking to the plasma membrane is impaired with an accumulation in intracellular organelles. In conclusion, our study sets several firm points on largely disputed matters, namely expression of mGluR1γ and role of the C-terminal domain of mGluR1 splice variants on their perisynaptic clustering.
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Affiliation(s)
- Rika Naito
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Hidetoshi Kassai
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Division of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yusuke Sakai
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Sabine Schönherr
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - Kazuki Nakao
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Atsu Aiba
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Division of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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29
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Oh JY, Lim CS, Yoo KS, Park H, Park YS, Kim EG, Lee YS, Kaang BK, Kim HK. Adenomatous polyposis coli-stimulated GEF 1 (Asef1) is a negative regulator of excitatory synaptic function. J Neurochem 2018; 147:595-608. [PMID: 30125942 DOI: 10.1111/jnc.14570] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/18/2018] [Accepted: 08/16/2018] [Indexed: 01/06/2023]
Abstract
Guanine nucleotide exchange factors (GEFs) play important roles in many cellular processes, including regulation of the structural plasticity of dendritic spines. A GEF protein, adenomatous polyposis coli-stimulated GEF 1 (Asef1, ARHGEF4) is highly expressed in the nervous system. However, the function of Asef1 has not been investigated in neurons. Here, we present evidence showing that Asef1 negatively regulates the synaptic localization of postsynaptic density protein 95 (PSD-95) in the excitatory synapse by inhibiting Staufen-mediated synaptic localization of PSD-95. Accordingly, Asef1 expression impairs synaptic transmission in hippocampal cultured neurons. In addition, neuronal activity facilitates the dissociation of Asef1 from Staufen in a phosphoinositide 3 kinase (PI3K)-dependent manner. Taken together, our data reveal Asef1 functions as a negative regulator of synaptic localization of PSD-95 and synaptic transmission.
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Affiliation(s)
- Jun-Young Oh
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea.,Korea Brain Research Institute, Daegu, Korea
| | - Chae-Seok Lim
- Department of Pharmacology, Wonkwang University School of Medicine, Iksan, Korea
| | - Ki-Seo Yoo
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea
| | | | - Young Seok Park
- Department of Neurosurgery, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Eung-Gook Kim
- Department of Medicine and Biochemistry, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Yong-Seok Lee
- Department of Physiology, Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Hyong Kyu Kim
- Graduate Program in Neuroscience, Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Korea
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Lagache T, Grassart A, Dallongeville S, Faklaris O, Sauvonnet N, Dufour A, Danglot L, Olivo-Marin JC. Mapping molecular assemblies with fluorescence microscopy and object-based spatial statistics. Nat Commun 2018; 9:698. [PMID: 29449608 PMCID: PMC5814551 DOI: 10.1038/s41467-018-03053-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/17/2018] [Indexed: 12/20/2022] Open
Abstract
Elucidating protein functions and molecular organisation requires to localise precisely single or aggregated molecules and analyse their spatial distributions. We develop a statistical method SODA (Statistical Object Distance Analysis) that uses either micro- or nanoscopy to significantly improve on standard co-localisation techniques. Our method considers cellular geometry and densities of molecules to provide statistical maps of isolated and associated (coupled) molecules. We use SODA with three-colour structured-illumination microscopy (SIM) images of hippocampal neurons, and statistically characterise spatial organisation of thousands of synapses. We show that presynaptic synapsin is arranged in asymmetric triangle with the 2 postsynaptic markers homer and PSD95, indicating a deeper localisation of homer. We then determine stoichiometry and distance between localisations of two synaptic vesicle proteins with 3D-STORM. These findings give insights into the protein organisation at the synapse, and prove the efficiency of SODA to quantitatively assess the geometry of molecular assemblies.
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Affiliation(s)
- Thibault Lagache
- Institut Pasteur, BioImage Analysis Unit. CNRS UMR 3691. 25 rue du Docteur Roux, 75724, Paris Cedex 15, France
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Alexandre Grassart
- Institut Pasteur, Molecular Microbial Pathogenesis Unit. INSERM U1202. 28 rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Stéphane Dallongeville
- Institut Pasteur, BioImage Analysis Unit. CNRS UMR 3691. 25 rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Orestis Faklaris
- CNRS UMR7592, Institut Jacques Monod, Université Paris Diderot, 15 rue Hélène Brion, 75013, Paris, France
| | - Nathalie Sauvonnet
- Institut Pasteur, Molecular Microbial Pathogenesis Unit. INSERM U1202. 28 rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Alexandre Dufour
- Institut Pasteur, BioImage Analysis Unit. CNRS UMR 3691. 25 rue du Docteur Roux, 75724, Paris Cedex 15, France
| | - Lydia Danglot
- Inserm U894 Center for Psychiatry and Neuroscience, Team Membrane traffic in healthy and diseased brain, 102-108 rue de la Santé, 75014, Paris, France.
| | - Jean-Christophe Olivo-Marin
- Institut Pasteur, BioImage Analysis Unit. CNRS UMR 3691. 25 rue du Docteur Roux, 75724, Paris Cedex 15, France.
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31
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Goulding SP, Szumlinski KK, Contet C, MacCoss MJ, Wu CC. A mass spectrometry-based proteomic analysis of Homer2-interacting proteins in the mouse brain. J Proteomics 2017; 166:127-137. [PMID: 28728878 DOI: 10.1016/j.jprot.2017.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 07/08/2017] [Accepted: 07/12/2017] [Indexed: 11/26/2022]
Abstract
In the brain, the Homer protein family modulates excitatory signal transduction and receptor plasticity through interactions with other proteins in dendritic spines. Homer proteins are implicated in a variety of psychiatric disorders such as schizophrenia and addiction. Since long Homers serve as scaffolding proteins, identifying their interacting partners is an important first step in understanding their biological function and could help to guide the design of new therapeutic strategies. The present study set out to document Homer2-interacting proteins in the mouse brain using a co-immunoprecipitation-based mass spectrometry approach where Homer2 knockout samples were used to filter out non-specific interactors. We found that in the mouse brain, Homer2 interacts with a limited subset of its previously reported interacting partners (3 out of 31). Importantly, we detected an additional 15 novel Homer2-interacting proteins, most of which are part of the N-methyl-D-aspartate receptor signaling pathway. These results corroborate the central role Homer2 plays in glutamatergic transmission and expand the network of proteins potentially contributing to the behavioral abnormalities associated with altered Homer2 expression. SIGNIFICANCE Long Homer proteins are scaffolding proteins that regulate signal transduction in neurons. Identifying their interacting partners is key to understanding their function. We used co-immunoprecipitation in combination with mass spectrometry to establish the first comprehensive list of Homer2-interacting partners in the mouse brain. The specificity of interactions was evaluated using Homer2 knockout brain tissue as a negative control. The set of proteins that we identified minimally overlaps with previously reported interacting partners of Homer2; however, we identified novel interactors that are part of a signaling cascade activated by glutamatergic transmission, which improves our mechanistic understanding of the role of Homer2 in behavior.
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Affiliation(s)
- Scott P Goulding
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, United States; Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, United States.
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, Molecular, Cellular and Developmental Biology, The Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Candice Contet
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, United States
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, United States
| | - Christine C Wu
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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A novel synaptic junction preparation for the identification and characterization of cleft proteins. PLoS One 2017; 12:e0174895. [PMID: 28362857 PMCID: PMC5376301 DOI: 10.1371/journal.pone.0174895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/16/2017] [Indexed: 12/23/2022] Open
Abstract
Identification of synaptic cleft components has been hampered by the lack of a suitable preparation enriched in synaptic junctions devoid of adjoining peripheral membranes. Prior strategies for the isolation of synaptic junctions, relying on detergents for the removal of peripheral membranes, resulted in substantial loss of membranes lining the cleft. Here, a novel, detergent-free method is described for the preparation of a synaptic junction (SJ) fraction, using phospholipase A2. Limited digestion of synaptic plasma membrane (SPM) fraction with phospholipase A2 followed by centrifugation over a sucrose cushion results in selective removal of membranes peripheral to the cleft while junctional membranes remain relatively intact as observed by electron microscopy. Enrichment in synaptic junctional structures and loss of membranes peripheral to the junctional area are further verified by demonstrating enrichment in PSD-95 and loss in mGluR5, respectively. The SJ fraction is enriched in neuroligins and neurexins, in agreement with immuno-electron microscopy data showing their selective localization to the junctional area. Among additional cell adhesion molecules tested, N-cadherin and specific isoforms of the SynCAM and SALM families also show marked enrichment in the SJ fraction, suggesting preferential localization at the synaptic cleft while others show little enrichment or decrease, suggesting that they are not restricted to or concentrated at the synaptic cleft. Treatment of the SJ fraction with glycosidases results in electrophoretic mobility shifts of all cell adhesion molecules tested, indicating glycosylation at the synaptic cleft. Biochemical and ultrastructural data presented indicate that the novel synaptic junction preparation can be used as a predictive tool for the identification and characterization of the components of the synaptic cleft.
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Zimmermann J, Neuhuber WL, Raab M. Homer1 (VesL-1) in the rat esophagus: focus on myenteric plexus and neuromuscular junction. Histochem Cell Biol 2017; 148:189-206. [PMID: 28337539 DOI: 10.1007/s00418-017-1555-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2017] [Indexed: 12/20/2022]
Abstract
Homer1, a scaffolding protein of the postsynaptic density (PSD), enriched at excitatory synapses is known to anchor and modulate group I metabotropic glutamate receptors (mGluRs) and different channel- and receptor-proteins. Homer proteins are expressed in neurons of different brain regions, but also in non-neuronal tissues like skeletal muscle. Occurrence and location of Homer1 and mGluR5 in myenteric plexus and neuromuscular junctions (NMJ) of rat esophagus have yet not been characterized. We located Homer1 and mGluR5 immunoreactivity (-iry) in rat esophagus and focused on myenteric neurons, intraganglionic laminar endings (IGLEs) and NMJs, using double- and triple-label immunohistochemistry and confocal laser scanning microscopy. Homer1-iry was found in a subpopulation of vesicular glutamate transporter 2 (VGLUT2) positive IGLEs and cholinergic varicosities within myenteric ganglia, but neither in nitrergic nor cholinergic myenteric neuronal cell bodies. Homer1-iry was detected in 63% of esophageal and, for comparison, in 35% of sternomastoid NMJs. Besides the location in the PSD, Homer1-iry colocalized with cholinergic markers, indicating a presynaptic location in coarse VAChT/CGRP/NF200- immunoreactive (-ir) terminals of nucleus ambiguus neurons supplying striated esophageal muscle. mGluR5-iry was found in subpopulations of myenteric neuronal cell bodies, VGLUT2-ir IGLEs and cholinergic varicosities within the myenteric neuropil and NMJs of esophagus and sternomastoid muscles. Thus, Homer1 may anchor mGluR5 at presynaptic sites of cholinergic boutons at esophageal motor endplates, in a small subpopulation of VGLUT2-ir IGLEs and cholinergic varicosities within myenteric ganglia possibly modulating Ca2+-currents and neurotransmitter release.
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Affiliation(s)
- J Zimmermann
- Institut für Anatomie, Lehrstuhl I, Friedrich-Alexander-Universität, Krankenhausstr. 9, 91054, Erlangen, Germany
| | - W L Neuhuber
- Institut für Anatomie, Lehrstuhl I, Friedrich-Alexander-Universität, Krankenhausstr. 9, 91054, Erlangen, Germany
| | - M Raab
- Institut für Anatomie, Lehrstuhl I, Friedrich-Alexander-Universität, Krankenhausstr. 9, 91054, Erlangen, Germany.
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Castelli V, Brancato A, Cavallaro A, Lavanco G, Cannizzaro C. Homer2 and Alcohol: A Mutual Interaction. Front Psychiatry 2017; 8:268. [PMID: 29249995 PMCID: PMC5714871 DOI: 10.3389/fpsyt.2017.00268] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/17/2017] [Indexed: 01/05/2023] Open
Abstract
The past two decades of data derived from addicted individuals and preclinical animal models of addiction implicate a role for the excitatory glutamatergic transmission within the mesolimbic structures in alcoholism. The cellular localization of the glutamatergic receptor subtypes, as well as their signaling efficiency and function, are highly dependent upon discrete functional constituents of the postsynaptic density, including the Homer family of scaffolding proteins. The consequences of repeated alcohol administration on the expression of the Homer family proteins demonstrate a crucial and active role, particularly for the expression of Homer2 isoform, in regulating alcohol-induced behavioral and cellular neuroplasticity. The interaction between Homer2 and alcohol can be defined as a mutual relation: alcohol consumption enhances the expression of Homer2 protein isoform within the nucleus accumbens and the extended amygdala, cerebral areas where, in turn, Homer2 is able to mediate the development of the "pro-alcoholic" behavioral phenotype, as a consequence of the morpho-functional synaptic adaptations. Such findings are relevant for the detection of the strategic molecular components that prompt alcohol-induced functional and behavioral disarrangement as targets for future innovative treatment options.
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Affiliation(s)
- Valentina Castelli
- Department of Sciences for Health Promotion and Mother and Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Anna Brancato
- Department of Sciences for Health Promotion and Mother and Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Angela Cavallaro
- Department of Sciences for Health Promotion and Mother and Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Gianluca Lavanco
- Department of Sciences for Health Promotion and Mother and Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy
| | - Carla Cannizzaro
- Department of Sciences for Health Promotion and Mother and Child Care "G. D'Alessandro", University of Palermo, Palermo, Italy
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Wang GX, Smith SJ, Mourrain P. Sub-synaptic, multiplexed analysis of proteins reveals Fragile X related protein 2 is mislocalized in Fmr1 KO synapses. eLife 2016; 5. [PMID: 27770568 PMCID: PMC5098911 DOI: 10.7554/elife.20560] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/20/2016] [Indexed: 12/11/2022] Open
Abstract
The distribution of proteins within sub-synaptic compartments is an essential aspect of their neurological function. Current methodologies, such as electron microscopy (EM) and super-resolution imaging techniques, can provide the precise localization of proteins, but are often limited to a small number of one-time observations with narrow spatial and molecular coverage. The diversity of synaptic proteins and synapse types demands synapse analysis on a scale that is prohibitive with current methods. Here, we demonstrate SubSynMAP, a fast, multiplexed sub-synaptic protein analysis method using wide-field data from deconvolution array tomography (ATD). SubSynMAP generates probability distributions for that reveal the functional range of proteins within the averaged synapse of a particular class. This enables the differentiation of closely juxtaposed proteins. Using this method, we analyzed 15 synaptic proteins in normal and Fragile X mental retardation syndrome (FXS) model mouse cortex, and revealed disease-specific modifications of sub-synaptic protein distributions across synapse classes and cortical layers. DOI:http://dx.doi.org/10.7554/eLife.20560.001
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Affiliation(s)
- Gordon X Wang
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, United States.,Center for Sleep Sciences and Medicine, Stanford University School of Medicine, Stanford, United States.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Stephen J Smith
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States.,Allen Institute for Brain Science, Seattle, USA
| | - Philippe Mourrain
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, United States.,Center for Sleep Sciences and Medicine, Stanford University School of Medicine, Stanford, United States.,INSERM 1024, Ecole Normale Supérieure, Paris, France
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Dosemeci A, Weinberg RJ, Reese TS, Tao-Cheng JH. The Postsynaptic Density: There Is More than Meets the Eye. Front Synaptic Neurosci 2016; 8:23. [PMID: 27594834 PMCID: PMC4990544 DOI: 10.3389/fnsyn.2016.00023] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 07/25/2016] [Indexed: 11/28/2022] Open
Abstract
The postsynaptic density (PSD), apparent in electron micrographs as a dense lamina just beneath the postsynaptic membrane, includes a deeper layer, the “pallium”, containing a scaffold of Shank and Homer proteins. Though poorly defined in traditionally prepared thin-section electron micrographs, the pallium becomes denser and more conspicuous during intense synaptic activity, due to the reversible addition of CaMKII and other proteins. In this Perspective article, we review the significance of CaMKII-mediated recruitment of proteins to the pallium with respect to both the trafficking of receptors and the remodeling of spine shape that follow synaptic stimulation. We suggest that the level and duration of CaMKII translocation and activation in the pallium will shape activity-induced changes in the spine.
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Affiliation(s)
- Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA
| | - Richard J Weinberg
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill Chapel Hill, NC, USA
| | - Thomas S Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA
| | - Jung-Hwa Tao-Cheng
- Electron Microscopy Facility, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH) Bethesda, MD, USA
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Immunostaining for Homer reveals the majority of excitatory synapses in laminae I-III of the mouse spinal dorsal horn. Neuroscience 2016; 329:171-81. [PMID: 27185486 PMCID: PMC4915440 DOI: 10.1016/j.neuroscience.2016.05.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/01/2016] [Accepted: 05/06/2016] [Indexed: 12/25/2022]
Abstract
Identifying glutamatergic synapses is important for tracing synaptic circuits. Most proteins at glutamatergic synapses are masked by tissue fixation. Homer can reveal glutamatergic synapses without the need for antigen retrieval.
The spinal dorsal horn processes somatosensory information before conveying it to the brain. The neuronal organization of the dorsal horn is still poorly understood, although recent studies have defined several distinct populations among the interneurons, which account for most of its constituent neurons. All primary afferents, and the great majority of neurons in laminae I–III are glutamatergic, and a major factor limiting our understanding of the synaptic circuitry has been the difficulty in identifying glutamatergic synapses with light microscopy. Although there are numerous potential targets for antibodies, these are difficult to visualize with immunocytochemistry, because of protein cross-linking following tissue fixation. Although this can be overcome by antigen retrieval methods, these lead to difficulty in detecting other antigens. The aim of this study was to test whether the postsynaptic protein Homer can be used to reveal glutamatergic synapses in the dorsal horn. Immunostaining for Homer gave punctate labeling when viewed by confocal microscopy, and this was restricted to synapses at the ultrastructural level. We found that Homer puncta were colocalized with the AMPA receptor GluR2 subunit, but not with the inhibitory synapse-associated protein gephyrin. We also examined several populations of glutamatergic axons and found that most boutons were in contact with at least one Homer punctum. These results suggest that Homer antibodies can be used to reveal the great majority of glutamatergic synapses without antigen retrieval. This will be of considerable value in tracing synaptic circuits, and also in investigating plasticity of glutamatergic synapses in pain states.
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Zinc Stabilizes Shank3 at the Postsynaptic Density of Hippocampal Synapses. PLoS One 2016; 11:e0153979. [PMID: 27144302 PMCID: PMC4856407 DOI: 10.1371/journal.pone.0153979] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/06/2016] [Indexed: 12/18/2022] Open
Abstract
Shank3 is a postsynaptic density (PSD) scaffold protein of the Shank family. Here we use pre-embedding immunogold electron microscopy to investigate factors influencing the distribution of Shank3 at the PSD. In dissociated rat hippocampal cultures under basal conditions, label for Shank3 was concentrated in a broad layer of the PSD, ~20–80 nm from the postsynaptic membrane. Upon depolarization with high K+ (90 mM, 2 min), or application of NMDA (50 μM, 2 min), both the labeling intensity at the PSD and the median distance of label from the postsynaptic membrane increased significantly, indicating that Shank3 molecules are preferentially recruited to the distal layer of the PSD. Incubation in medium supplemented with zinc (50 μM ZnCl2, 1 hr) also significantly increased labeling intensity for Shank3 at the PSD, but this addition of Shank3 was not preferential to the distal layer. When cells were incubated with zinc and then treated with NMDA, labeling intensity of Shank3 became higher than with either treatment alone and manifested a preference for the distal layer of the PSD. Without zinc supplementation, NMDA-induced accumulation of Shank3 at the PSD was transient, reversing within 30 min after return to control medium. However, when zinc was included in culture media throughout the experiment, the NMDA-induced accumulation of Shank3 was largely retained, including Shank3 molecules recruited to the distal layer of the PSD. These results demonstrate that activity induces accumulation of Shank3 at the PSD and that zinc stabilizes PSD-associated Shank3, possibly through strengthening of Shank-Shank association.
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Depolarization of Hippocampal Neurons Induces Formation of Nonsynaptic NMDA Receptor Islands Resembling Nascent Postsynaptic Densities. eNeuro 2015; 2:eN-NWR-0066-15. [PMID: 26665164 PMCID: PMC4672205 DOI: 10.1523/eneuro.0066-15.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 10/15/2015] [Accepted: 11/03/2015] [Indexed: 01/11/2023] Open
Abstract
Depolarization of neurons in 3-week-old rat hippocampal cultures promotes a rapid increase in the density of surface NMDA receptors (NRs), accompanied by transient formation of nonsynaptic NMDA receptor clusters or NR islands. Islands exhibit cytoplasmic dense material resembling that at postsynaptic densities (PSDs), and contain typical PSD components, including MAGUKS (membrane-associated guanylate kinases), GKAP, Shank, Homer, and CaMKII detected by pre-embedding immunogold electron microscopy. In contrast to mature PSDs, islands contain more NMDA than AMPA receptors, and more SAP102 than PSD-95, features that are shared with nascent PSDs in developing synapses. Islands do not appear to be exocytosed or endocytosed directly as preformed packages because neurons lacked intracellular vacuoles containing island-like structures. Islands form and disassemble upon depolarization of neurons on a time scale of 2-3 min, perhaps representing an initial stage in synaptogenesis.
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Dosemeci A, Toy D, Reese TS, Tao-Cheng JH. AIDA-1 Moves out of the Postsynaptic Density Core under Excitatory Conditions. PLoS One 2015; 10:e0137216. [PMID: 26356309 PMCID: PMC4565644 DOI: 10.1371/journal.pone.0137216] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/13/2015] [Indexed: 11/18/2022] Open
Abstract
AIDA-1 is highly enriched in postsynaptic density (PSD) fractions and is considered a major component of the PSD complex. In the present study, immunogold electron microscopy was applied to determine localization as well as the activity-induced redistribution of AIDA-1 at the PSD using two antibodies that recognize two different epitopes. In cultured rat hippocampal neurons under basal conditions, immunogold label for AIDA-1 is mostly located within the dense core of the PSD, with a median distance of ~30 nm from the postsynaptic membrane. Under excitatory conditions, such as depolarization with high K+ (90 mM, 2 min) or application of NMDA (50 μM, 2 min), AIDA-1 label density at the PSD core is reduced to 40% of controls and the median distance of label from the postsynaptic membrane increases to ~55 nm. The effect of excitatory conditions on the postsynaptic distribution of AIDA-1 is reversed within 30 minutes after returning to control conditions. The reversible removal of AIDA-1 from the PSD core under excitatory conditions is similar to the redistribution of another abundant PSD protein, SynGAP. Both SynGAP-alpha1 and AIDA-1 are known to bind PSD-95. Activity-induced transient translocation of these abundant proteins from the PSD core could promote structural flexibility, vacate sites on PSD-95 for the insertion of other components and thus may create a window for synaptic modification.
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Affiliation(s)
- Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Dana Toy
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jung-Hwa Tao-Cheng
- EM Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
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Tao-Cheng JH, Yang Y, Reese TS, Dosemeci A. Differential distribution of Shank and GKAP at the postsynaptic density. PLoS One 2015; 10:e0118750. [PMID: 25775468 PMCID: PMC4361712 DOI: 10.1371/journal.pone.0118750] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/06/2015] [Indexed: 11/18/2022] Open
Abstract
Shank and GKAP are scaffold proteins and binding partners at the postsynaptic density (PSD). The distribution and dynamics of Shank and GKAP were studied in dissociated hippocampal cultures by pre-embedding immunogold electron microscopy. Antibodies against epitopes containing their respective mutual binding sites were used to verify the expected juxtapositioning of Shank and GKAP. If all Shank and GKAP molecules at the PSD were bound to each other, the distribution of label for the two proteins should coincide. However, labels for the mutual binding sites showed significant differences in distribution, with a narrow distribution for GKAP located close to the postsynaptic membrane, and a wider distribution for Shank extending deeper into the cytoplasm. Upon depolarization with high K+, neither the intensity nor distribution of label for GKAP changed, but labeling intensity for Shank at the PSD increased to ~150% of controls while the median distance of label from postsynaptic membrane increased by 7.5 nm. These results indicate a preferential recruitment of Shank to more distal parts of the PSD complex. Conversely, upon incubation in Ca2+-free medium containing EGTA, the labeling intensity of Shank at the PSD decreased to ~70% of controls and the median distance of label from postsynaptic membrane decreased by 9 nm, indicating a preferential loss of Shank molecules in more distal parts of the PSD complex. These observations identify two pools of Shank at the PSD complex, one relatively stable pool, closer to the postsynaptic membrane that can bind to GKAP, and another more dynamic pool at a location too far away to bind to GKAP.
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Affiliation(s)
- Jung-Hwa Tao-Cheng
- EM Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Yijung Yang
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
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NMDA-induced accumulation of Shank at the postsynaptic density is mediated by CaMKII. Biochem Biophys Res Commun 2014; 450:808-11. [PMID: 24952157 DOI: 10.1016/j.bbrc.2014.06.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 11/24/2022]
Abstract
Shank is a specialized scaffold protein present in high abundance at the postsynaptic density (PSD). Using pre-embedding immunogold electron microscopy on cultured hippocampal neurons, we had previously demonstrated further accumulation of Shank at the PSD under excitatory conditions. Here, using the same experimental protocol, we demonstrate that a cell permeable CaMKII inhibitor, tatCN21, blocks NMDA-induced accumulation of Shank at the PSD. Furthermore we show that NMDA application changes the distribution pattern of Shank at the PSD, promoting a 7-10 nm shift in the median distance of Shank labels away from the postsynaptic membrane. Inhibition of CaMKII with tatCN21 also blocks this shift in the distribution of Shank. Altogether these results imply that upon activation of NMDA receptors, CaMKII mediates accumulation of Shank, preferentially at the distal regions of the PSD complex extending toward the cytoplasm.
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