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Coulon A, Siedlecki-Wullich D, Najdek C, Gelle C, Ayral AM, Demiautte F, Lambert E, Vandeputte A, Brodin P, Mendes T, Lambert JC, Kilinc D, Dumont J, Chapuis J. High-Content Screening of Synaptic Density Modulators in Primary Neuronal Cultures. Curr Protoc 2023; 3:e904. [PMID: 37882787 DOI: 10.1002/cpz1.904] [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] [Indexed: 10/27/2023]
Abstract
The synapse, which represents the structural and functional basis of neuronal communication, is one of the first elements affected in several neurodegenerative diseases. To better understand the potential role of gene expression in synapse loss, we developed an original high-content screening (HCS) model capable of quantitatively assessing the impact of gene silencing on synaptic density. Our approach is based on a model of primary neuronal cultures (PNCs) from the neonatal rat hippocampus, whose mature synapses are visualized by the relative localization of the presynaptic protein Synaptophysin with the postsynaptic protein Homer1. The heterogeneity of PNCs and the small sizes of the synaptic structures pose technical challenges associated with the level of automation necessary for HCS studies. We overcame these technical challenges, automated the processes of image analysis and data analysis, and carried out tests under real-world conditions to demonstrate the robustness of the model developed. In this article, we describe the screening of a custom library of 198 shRNAs in PNCs in the 384-well plate format. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culture of primary hippocampal rat neurons in 384-well plates Basic Protocol 2: Lentiviral shRNA transduction of primary neuronal culture in 384-well plates Basic Protocol 3: Immunostaining of the neuronal network and synaptic markers in 384-well plates Basic Protocol 4: Image acquisition using a high-throughput reader Basic Protocol 5: Image segmentation and analysis Basic Protocol 6: Synaptic density analysis.
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Affiliation(s)
- Audrey Coulon
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Dolores Siedlecki-Wullich
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Chloé Najdek
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Carla Gelle
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Anne-Marie Ayral
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Florie Demiautte
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Erwan Lambert
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Alexandre Vandeputte
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille (CIIL), Lille, France
| | - Priscille Brodin
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille (CIIL), Lille, France
| | - Tiago Mendes
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Jean-Charles Lambert
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Devrim Kilinc
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Julie Dumont
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
| | - Julien Chapuis
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, Lille, France
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Suresh J, Saddler M, Bindokas V, Bhansali A, Pesce L, Wang J, Marks J, van Drongelen W. Emerging Activity Patterns and Synaptogenesis in Dissociated Hippocampal Cultures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.541345. [PMID: 37292953 PMCID: PMC10245748 DOI: 10.1101/2023.05.18.541345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cultures of dissociated hippocampal neurons display a stereotypical development of network activity patterns within the first three weeks of maturation. During this process, network connections develop and the associated spiking patterns range from increasing levels of activity in the first two weeks to regular bursting activity in the third week of maturation. Characterization of network structure is important to examine the mechanisms underlying the emergent functional organization of neural circuits. To accomplish this, confocal microscopy techniques have been used and several automated synapse quantification algorithms based on (co)localization of synaptic structures have been proposed recently. However, these approaches suffer from the arbitrary nature of intensity thresholding and the lack of correction for random-chance colocalization. To address this problem, we developed and validated an automated synapse quantification algorithm that requires minimal operator intervention. Next, we applied our approach to quantify excitatory and inhibitory synaptogenesis using confocal images of dissociated hippocampal neuronal cultures captured at 5, 8, 14 and 20 days in vitro, the time period associated with the development of distinct neuronal activity patterns. As expected, we found that synaptic density increased with maturation, coinciding with increasing spiking activity in the network. Interestingly, the third week of the maturation exhibited a reduction in excitatory synaptic density suggestive of synaptic pruning that coincided with the emergence of regular bursting activity in the network.
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Affiliation(s)
- Jyothsna Suresh
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Computational Neuroscience, The University of Chicago, Chicago, IL 60637, USA
| | - Mark Saddler
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - Vytas Bindokas
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, IL 60637, USA
| | - Anita Bhansali
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - Lorenzo Pesce
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - Janice Wang
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - Jeremy Marks
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Wim van Drongelen
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
- Committee on Computational Neuroscience, The University of Chicago, Chicago, IL 60637, USA
- Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA
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3
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Berryer MH, Rizki G, Nathanson A, Klein JA, Trendafilova D, Susco SG, Lam D, Messana A, Holton KM, Karhohs KW, Cimini BA, Pfaff K, Carpenter AE, Rubin LL, Barrett LE. High-content synaptic phenotyping in human cellular models reveals a role for BET proteins in synapse assembly. eLife 2023; 12:80168. [PMID: 37083703 PMCID: PMC10121225 DOI: 10.7554/elife.80168] [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: 05/11/2022] [Accepted: 04/10/2023] [Indexed: 04/22/2023] Open
Abstract
Resolving fundamental molecular and functional processes underlying human synaptic development is crucial for understanding normal brain function as well as dysfunction in disease. Based upon increasing evidence of species-divergent features of brain cell types, coupled with emerging studies of complex human disease genetics, we developed the first automated and quantitative high-content synaptic phenotyping platform using human neurons and astrocytes. To establish the robustness of our platform, we screened the effects of 376 small molecules on presynaptic density, neurite outgrowth, and cell viability, validating six small molecules that specifically enhanced human presynaptic density in vitro. Astrocytes were essential for mediating the effects of all six small molecules, underscoring the relevance of non-cell-autonomous factors in synapse assembly and their importance in synaptic screening applications. Bromodomain and extraterminal (BET) inhibitors emerged as the most prominent hit class and global transcriptional analyses using multiple BET inhibitors confirmed upregulation of synaptic gene expression. Through these analyses, we demonstrate the robustness of our automated screening platform for identifying potent synaptic modulators, which can be further leveraged for scaled analyses of human synaptic mechanisms and drug discovery efforts.
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Affiliation(s)
- Martin H Berryer
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Gizem Rizki
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Anna Nathanson
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Jenny A Klein
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Darina Trendafilova
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Sara G Susco
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Daisy Lam
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Angelica Messana
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Kristina M Holton
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Kyle W Karhohs
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Beth A Cimini
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Kathleen Pfaff
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Anne E Carpenter
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Lee L Rubin
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
| | - Lindy E Barrett
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, United States
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, United States
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Microglia involvement in sex-dependent behaviors and schizophrenia occurrence in offspring with maternal dexamethasone exposure. SCHIZOPHRENIA 2022; 8:71. [PMID: 36075925 PMCID: PMC9458670 DOI: 10.1038/s41537-022-00280-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/27/2022] [Indexed: 12/30/2022]
Abstract
Fetal microglia that are particularly sensitive cells to the changes in utero environment might be involved in the sex-biased onset and vulnerability to psychiatric disorders. To address this issue, we administered a 50 µg/kg dexamethasone (DEX) to dams subcutaneously from gestational days 16 to 18 and a series of behavioral assessments were performed in the offspring. Prenatal exposure to dexamethasone (PN-DEX) induced schizophrenia (SCZ)-relevant behaviors in male mice and depressive-like behavior in female mice. SCZ-relevant behavioral patterns occurred in 10-week-old (10 W) male mice but not in 4-week-old (4 W) male mice. Microglia in the medial prefrontal cortex (mPFC) and the striatum (STR) of 10 W males prenatally treated with dexamethasone (10 W PN-DEX-M) showed hyper-ramified morphology and dramatically reduced spine density in mPFC. Immunofluorescence studies indicated that microglia in the mPFC of the 10 W PN-DEX-M group interacted with pre-synaptic Bassoon and post-synaptic density 95 (PSD95) puncta. PN-DEX-M also showed significantly changed dopamine system proteins. However, a testosterone surge during adolescence was not a trigger on SCZ-relevant behavior occurrence in 10 W PN-DEX-M. Furthermore, females prenatally treated with dexamethasone (PN-DEX-F) displayed depressive-like behavior, in addition to HPA-axis activation and inflammatory microglial phenotypes in their hippocampus (HPC). We propose that altered microglial function, such as increased synaptic pruning, may be involved in the occurrence of SCZ-relevant behavior in PN-DEX-M and sex-biased abnormal behavior in the PN-DEX model.
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Tacke C, DiStefano PS, Lindsay RM, Metzdorf K, Zagrebelsky M, Korte M. Actions of the TrkB Agonist Antibody ZEB85 in Regulating the Architecture and Synaptic Plasticity in Hippocampal Neurons. Front Mol Neurosci 2022; 15:945348. [PMID: 35845610 PMCID: PMC9280622 DOI: 10.3389/fnmol.2022.945348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Signaling of BDNF via its TrkB receptor is crucial in regulating several critical aspects of the architecture and function of neurons both during development and in the adult central nervous system. Indeed, several neurological conditions, such as neurodevelopmental and neurodegenerative disorders are associated with alterations both in the expression levels of BDNF and TrkB, and in their intracellular signaling. Thus, the possibility of promoting BDNF/TrkB signaling has become relevant as a potential therapeutic intervention for neurological disorders. However, the clinical potential of BDNF itself has been limited due to its restricted diffusion rate in biological tissue, poor bioavailability and pharmacological properties, as well as the potential for unwanted side effects due to its ability to also signal via the p75NTR pathway. Several small molecule and biologic drug candidate TrkB agonists have been developed and are reported to have effects in rescuing both the pathological alterations and disease related symptoms in mouse models of several neurological diseases. However, recent side-by-side comparative studies failed to show their specificity for activating TrkB signaling cascades, suggesting the need for the generation and validation of improved candidates. In the present study, we examine the ability of the novel, fully human TrkB agonist antibody ZEB85 to modulate the architecture, activity and synaptic plasticity of hippocampal murine neurons under physiological conditions. Moreover, we show here that ZEB85 prevents β-amyloid toxicity in cultured hippocampal neurons, in a manner which is comparable to BDNF.
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Affiliation(s)
- Charlotte Tacke
- Division of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
- *Correspondence: Charlotte Tacke,
| | | | | | - Kristin Metzdorf
- Division of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Research Group Neuroinflammation and Neurodegeneration (AG NIND), Braunschweig, Germany
| | - Marta Zagrebelsky
- Division of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
- Marta Zagrebelsky,
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
- Helmholtz Centre for Infection Research, Research Group Neuroinflammation and Neurodegeneration (AG NIND), Braunschweig, Germany
- Martin Korte,
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S-SCAM inhibits Axin-dependent synaptic function of GSK3β in a sex-dependent manner. Sci Rep 2022; 12:4090. [PMID: 35260764 PMCID: PMC8904762 DOI: 10.1038/s41598-022-08220-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 03/04/2022] [Indexed: 11/12/2022] Open
Abstract
S-SCAM/MAGI-2 gene duplication is associated with schizophrenia (SCZ). S-SCAM overexpression in the forebrain induces SCZ-like phenotypes in a transgenic (Tg) mouse model. Interestingly, S-SCAM Tg mice show male-specific impairments in synaptic plasticity and working memory. However, mechanisms underlying the sex-specific deficits remain unknown. Here we report that S-SCAM Tg mice have male-specific deficits in synaptic GSK3β functions, as shown by reduced synaptic protein levels and increased inhibitory phosphorylation of GSK3β. This GSK3β hyper-phosphorylation was associated with increased CaMKII activities. Notably, synaptic levels of Axin1, to which GSK3β binds in competition with S-SCAM, were also reduced in male S-SCAM Tg mice. We demonstrated that Axin-binding is required for the S-SCAM overexpression-induced synaptic GSK3β reduction. Axin stabilization using XAV939 rescued the GSK3β deficits and restored the temporal activation of GSK3β during long-term depression in S-SCAM overexpressing neurons. Interestingly, synaptic Axin2 levels were increased in female S-SCAM Tg mice. Female sex hormone 17β-estradiol increased Axin2 expression and increased synaptic GSK3β levels in S-SCAM overexpressing neurons. These results reveal the role of S-SCAM in controlling Axin-dependent synaptic localization of GSK3β. Moreover, our studies point out the pathological relevance of GSK3β hypofunction found in humans and contribute to understanding the molecular underpinnings of sex differences in SCZ.
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Pchitskaya E, Rakovskaya A, Chigray M, Bezprozvanny I. Cytoskeleton Protein EB3 Contributes to Dendritic Spines Enlargement and Enhances Their Resilience to Toxic Effects of Beta-Amyloid. Int J Mol Sci 2022; 23:2274. [PMID: 35216391 PMCID: PMC8875759 DOI: 10.3390/ijms23042274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 11/16/2022] Open
Abstract
EB3 protein is expressed abundantly in the nervous system and transiently enters the dendritic spines at the tip of the growing microtubule, which leads to spine enlargement. Nevertheless, the role of dynamic microtubules, and particularly EB3 protein, in synapse function is still elusive. By manipulating the EB3 expression level, we have shown that this protein is required for a normal dendritogenesis. Nonetheless, EB3 overexpression also reduces hippocampal neurons dendritic branching and total dendritic length. This effect likely occurs due to the speeding neuronal development cycle from dendrite outgrowth to the step when dendritic spines are forming. Implementing direct morphometric characterization of dendritic spines, we showed that EB3 overexpression leads to a dramatic increase in the dendritic spine head area. EB3 knockout oppositely reduces spine head area and increases spine neck length and spine neck/spine length ratio. The same effect is observed in conditions of amyloid-beta toxicity, modeling Alzheimer`s disease. Neck elongation is supposed to be a common detrimental effect on the spine's shape, which makes them biochemically and electrically less connected to the dendrite. EB3 also potentiates the formation of presynaptic protein Synapsin clusters and CaMKII-alpha preferential localization in spines rather than in dendrites of hippocampal neurons, while its downregulation has an opposite effect and reduces the size of presynaptic protein clusters Synapsin and PSD95. EB3's role in spine development and maturation determines its neuroprotective effect. EB3 overexpression makes dendritic spines resilient to amyloid-beta toxicity, restores altered PSD95 clustering, and reduces CaMKII-alpha localization in spines observed in this pathological state.
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Affiliation(s)
- Ekaterina Pchitskaya
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (E.P.); (A.R.); (M.C.)
| | - Anastasiya Rakovskaya
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (E.P.); (A.R.); (M.C.)
| | - Margarita Chigray
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (E.P.); (A.R.); (M.C.)
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, Khlopina St. 11, 194021 St. Petersburg, Russia; (E.P.); (A.R.); (M.C.)
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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Guhathakurta D, Akdaş EY, Fejtová A, Weiss EM. Development and Application of Automatized Routines for Optical Analysis of Synaptic Activity Evoked by Chemical and Electrical Stimulation. FRONTIERS IN BIOINFORMATICS 2022; 2:814081. [PMID: 36304276 PMCID: PMC9580924 DOI: 10.3389/fbinf.2022.814081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/24/2022] [Indexed: 11/24/2022] Open
Abstract
The recent development of cellular imaging techniques and the application of genetically encoded sensors of neuronal activity led to significant methodological progress in neurobiological studies. These methods often result in complex and large data sets consisting of image stacks or sets of multichannel fluorescent images. The detection of synapses, visualized by fluorescence labeling, is one major challenge in the analysis of these datasets, due to variations in synapse shape, size, and fluorescence intensity across the images. For their detection, most labs use manual or semi-manual techniques that are time-consuming and error-prone. We developed SynEdgeWs, a MATLAB-based segmentation algorithm that combines the application of an edge filter, morphological operators, and marker-controlled watershed segmentation. SynEdgeWs does not need training data and works with low user intervention. It was superior to methods based on cutoff thresholds and local maximum guided approaches in a realistic set of data. We implemented SynEdgeWs in two automatized routines that allow accurate, direct, and unbiased identification of fluorescently labeled synaptic puncta and their consecutive analysis. SynEval routine enables the analysis of three-channel images, and ImgSegRout routine processes image stacks. We tested the feasibility of ImgSegRout on a realistic live-cell imaging data set from experiments designed to monitor neurotransmitter release using synaptic phluorins. Finally, we applied SynEval to compare synaptic vesicle recycling evoked by electrical field stimulation and chemical depolarization in dissociated cortical cultures. Our data indicate that while the proportion of active synapses does not differ between stimulation modes, significantly more vesicles are mobilized upon chemical depolarization.
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Affiliation(s)
| | | | - Anna Fejtová
- *Correspondence: Anna Fejtová, ; Eva-Maria Weiss,
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Wasilewski D, Villalba-Moreno ND, Stange I, Glatzel M, Sepulveda-Falla D, Krasemann S. Reactive Astrocytes Contribute to Alzheimer’s Disease-Related Neurotoxicity and Synaptotoxicity in a Neuron-Astrocyte Co-culture Assay. Front Cell Neurosci 2022; 15:739411. [PMID: 35126055 PMCID: PMC8813976 DOI: 10.3389/fncel.2021.739411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 12/08/2021] [Indexed: 01/14/2023] Open
Abstract
Pathological hallmarks of Alzheimer’s disease (AD) include deposition and accumulation of amyloid- β (Aβ), neurofibrillary tangle formation, and neuronal loss. Pathogenesis of presymptomatic disease stages remains elusive, although studies suggest that the early structural and functional alterations likely occur at neuronal dendritic spines. Presymptomatic alterations may also affect different CNS cell types. However, specific contributions of these cell types as cause or consequence of pathology are difficult to study in vivo. There is a shortage of relatively simple, well-defined, and validated in vitro models that allow a straightforward interpretation of results and recapitulate aspects of pathophysiology. For instance, dissecting the AD-related processes (e.g., neurotoxicity vs. synaptotoxicity) may be difficult with the common cell-based systems such as neuronal cell lines or primary neurons. To investigate and characterize the impact of reactive astrocytes on neuronal morphology in the context of AD-related cues, we modified an in vitro co-culture assay of primary mouse neurons and primary mouse astrocytes based on the so-called Banker “sandwich” co-culture assay. Here, we provide a simple and modular assay with fully differentiated primary mouse neurons to study the paracrine interactions between the neurons and the astrocytes in the co-culture setting. Readouts were obtained from both cell types in our assay. Astrocyte feeder cells were pre-exposed to neuroinflammatory conditions by means of Aβ42, Aβ40, or lipopolysaccharide (LPS). Non-cell autonomous toxic effects of reactive astrocytes on neurons were assessed using the Sholl analysis to evaluate the dendritic complexity, whereas synaptic puncta served as a readout of synaptotoxicity. Here, we show that astrocytes actively contribute to the phenotype of the primary neurons in an AD-specific context, emphasizing the role of different cell types in AD pathology. The cytokine expression pattern was significantly altered in the treated astrocytes. Of note, the impact of reactive astrocytes on neurons was highly dependent on the defined cell ratios. Our co-culture system is modular, of low cost, and allows us to probe aspects of neurodegeneration and neuroinflammation between the two major CNS cell types, neurons, and astrocytes, under well-defined experimental conditions. Our easy-to-follow protocol, including work-flow figures, may also provide a methodological outline to study the interactions of astrocytes and neurons in the context of other diseases in the future.
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Song Y, Du Z, Chen X, Zhang W, Zhang G, Li H, Chang L, Wu Y. Astrocytic N-Methyl-D-Aspartate Receptors Protect the Hippocampal Neurons Against Amyloid-β142-Induced Synaptotoxicity by Regulating Nerve Growth Factor. J Alzheimers Dis 2021; 85:167-178. [PMID: 34776441 DOI: 10.3233/jad-210730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Soluble oligomeric amyloid-β (Aβ)-induced synaptic dysfunction is an early event in Alzheimer's disease (AD) pathogenesis. Mounting evidence has suggested N-methyl-D-aspartate receptors (NMDARs) play an important role in Aβ-induced synaptotoxicity. Originally NMDARs were believed to be expressed exclusively in neurons; however, recent two decades studies have demonstrated functional NMDARs present on astrocytes. Neuronal NMDARs are modulators of neurodegeneration, while our previous initial study found that astrocytic NMDARs mediated synaptoprotection and identified nerve growth factor (NGF) secreted by astrocytes, as a likely mediator, but how astrocytic NMDARs protect neurons against Aβ-induced synaptotoxicity through regulating NGF remains unclear. OBJECTIVE To achieve further insight into the mechanism of astrocytic NMDARs oppose Aβ-induced synaptotoxicity through regulating NGF. METHODS With the primary hippocampal neuronal and astrocytic co-cultures, astrocytes were pretreated with agonist or antagonist of NMDARs before Aβ142 oligomers application to neuron-astrocyte co-cultures. Western blot, RT-PCR, etc., were used for the related proteins evaluation. RESULTS Activation of astrocytic NMDARs can significantly mitigate Aβ142-induced loss of PSD-95 and synaptophysin through increasing NGF release. Blockade of astrocytic NMDARs inhibited Aβ-induced compensatory protective NGF increase in protein and mRNA levels through modulating NF-κB of astrocytes. Astrocytic NMDARs activation can enhance Aβ-induced Furin increase, and blockade of astrocytic NMDARs inhibited Aβ-induced immunofluorescent intensity elevation of vesicle trafficking protein VAMP3 and NGF double-staining. CONCLUSION Astrocytic NMDARs oppose Aβ-induced synaptotoxicity through modulating the synthesis, maturation, and secretion of NGF in astrocytes. This new information may contribute to the quest for specific targeted strategy of intervention to delay the onset of AD.
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Affiliation(s)
- Yizhi Song
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Zunshu Du
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Xinyue Chen
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Wanning Zhang
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Guitao Zhang
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Hui Li
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Lirong Chang
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Yan Wu
- Department of Anatomy, School of Basic MedicalSciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
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11
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Metzdorf K, Fricke S, Balia MT, Korte M, Zagrebelsky M. Nogo-A Modulates the Synaptic Excitation of Hippocampal Neurons in a Ca 2+-Dependent Manner. Cells 2021; 10:cells10092299. [PMID: 34571950 PMCID: PMC8467072 DOI: 10.3390/cells10092299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022] Open
Abstract
A tight regulation of the balance between inhibitory and excitatory synaptic transmission is a prerequisite for synaptic plasticity in neuronal networks. In this context, the neurite growth inhibitor membrane protein Nogo-A modulates synaptic plasticity, strength, and neurotransmitter receptor dynamics. However, the molecular mechanisms underlying these actions are unknown. We show that Nogo-A loss-of-function in primary mouse hippocampal cultures by application of a function-blocking antibody leads to higher excitation following a decrease in GABAARs at inhibitory and an increase in the GluA1, but not GluA2 AMPAR subunit at excitatory synapses. This unbalanced regulation of AMPAR subunits results in the incorporation of Ca2+-permeable GluA2-lacking AMPARs and increased intracellular Ca2+ levels due to a higher Ca2+ influx without affecting its release from the internal stores. Increased neuronal activation upon Nogo-A loss-of-function prompts the phosphorylation of the transcription factor CREB and the expression of c-Fos. These results contribute to the understanding of the molecular mechanisms underlying the regulation of the excitation/inhibition balance and thereby of plasticity in the brain.
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Affiliation(s)
- Kristin Metzdorf
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, D-38106 Braunschweig, Germany; (K.M.); (M.T.B.); (M.K.)
- Helmholtz Centre for Infection Research, AG NIND, Inhoffenstr. 7, D-38124 Braunschweig, Germany
| | - Steffen Fricke
- Division of Cell Physiology, Zoological Institute, TU Braunschweig, D-38106 Braunschweig, Germany;
| | - Maria Teresa Balia
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, D-38106 Braunschweig, Germany; (K.M.); (M.T.B.); (M.K.)
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, D-38106 Braunschweig, Germany; (K.M.); (M.T.B.); (M.K.)
- Helmholtz Centre for Infection Research, AG NIND, Inhoffenstr. 7, D-38124 Braunschweig, Germany
| | - Marta Zagrebelsky
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, D-38106 Braunschweig, Germany; (K.M.); (M.T.B.); (M.K.)
- Correspondence: ; Tel.: +49-(0)-531-3913225
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12
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Birsa N, Ule AM, Garone MG, Tsang B, Mattedi F, Chong PA, Humphrey J, Jarvis S, Pisiren M, Wilkins OG, Nosella ML, Devoy A, Bodo C, de la Fuente RF, Fisher EMC, Rosa A, Viero G, Forman-Kay JD, Schiavo G, Fratta P. FUS-ALS mutants alter FMRP phase separation equilibrium and impair protein translation. SCIENCE ADVANCES 2021; 7:7/30/eabf8660. [PMID: 34290090 PMCID: PMC8294762 DOI: 10.1126/sciadv.abf8660] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/03/2021] [Indexed: 05/16/2023]
Abstract
FUsed in Sarcoma (FUS) is a multifunctional RNA binding protein (RBP). FUS mutations lead to its cytoplasmic mislocalization and cause the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Here, we use mouse and human models with endogenous ALS-associated mutations to study the early consequences of increased cytoplasmic FUS. We show that in axons, mutant FUS condensates sequester and promote the phase separation of fragile X mental retardation protein (FMRP), another RBP associated with neurodegeneration. This leads to repression of translation in mouse and human FUS-ALS motor neurons and is corroborated in vitro, where FUS and FMRP copartition and repress translation. Last, we show that translation of FMRP-bound RNAs is reduced in vivo in FUS-ALS motor neurons. Our results unravel new pathomechanisms of FUS-ALS and identify a novel paradigm by which mutations in one RBP favor the formation of condensates sequestering other RBPs, affecting crucial biological functions, such as protein translation.
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Affiliation(s)
- Nicol Birsa
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
- UK Dementia Research Institute, University College London, London WC1E 6BT, UK
| | - Agnieszka M Ule
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Maria Giovanna Garone
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | - Brian Tsang
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Francesca Mattedi
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Institute of Biophysics, CNR, Trento, Italy
| | - P Andrew Chong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Jack Humphrey
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Seth Jarvis
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Melis Pisiren
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Oscar G Wilkins
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- The Francis Crick Institute, London NW1 1AT, UK
| | - Micheal L Nosella
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Anny Devoy
- Maurice Wohl Clinical Neuroscience Institute, King's College London, London SE5 9RT, UK
| | - Cristian Bodo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | | | - Elizabeth M C Fisher
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alessandro Rosa
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
- Center for Life Nano Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, 00161 Rome, Italy
| | | | - Julie D Forman-Kay
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- UK Dementia Research Institute, University College London, London WC1E 6BT, UK
| | - Pietro Fratta
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
- MRC Centre for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK
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13
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Ludewig S, Herrmann U, Michaelsen-Preusse K, Metzdorf K, Just J, Bold C, Müller UC, Korte M. APPsα rescues impaired Ca 2+ homeostasis in APP- and APLP2-deficient hippocampal neurons. Proc Natl Acad Sci U S A 2021; 118:e2011506118. [PMID: 34172567 PMCID: PMC8256088 DOI: 10.1073/pnas.2011506118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Alterations in Ca2+ homeostasis have been reported in several in vitro and in vivo studies using mice expressing the Alzheimer's disease-associated transgenes, presenilin and the amyloid precursor protein (APP). While intense research focused on amyloid-β-mediated functions on neuronal Ca2+ handling, the physiological role of APP and its close homolog APLP2 is still not fully clarified. We now elucidate a mechanism to show how APP and its homolog APLP2 control neuronal Ca2+ handling and identify especially the ectodomain APPsα as an essential regulator of Ca2+ homeostasis. Importantly, we demonstrate that the loss of APP and APLP2, but not APLP2 alone, impairs Ca2+ handling, the refill of the endoplasmic reticulum Ca2+ stores, and synaptic plasticity due to altered function and expression of the SERCA-ATPase and expression of store-operated Ca2+ channel-associated proteins Stim1 and Stim2. Long-term AAV-mediated expression of APPsα, but not acute application of the recombinant protein, restored physiological Ca2+ homeostasis and synaptic plasticity in APP/APLP2 cDKO cultures. Overall, our analysis reveals an essential role of the APP family and especially of the ectodomain APPsα in Ca2+ homeostasis, thereby highlighting its therapeutic potential.
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Affiliation(s)
- Susann Ludewig
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Ulrike Herrmann
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Kristin Michaelsen-Preusse
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Kristin Metzdorf
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Jennifer Just
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Charlotte Bold
- Department of Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
| | - Ulrike C Müller
- Department of Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany
| | - Martin Korte
- Department of Cellular Neurobiology Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany;
- Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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14
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Ingwersen T, Linnenberg C, D'Acunto E, Temori S, Paolucci I, Wasilewski D, Mohammadi B, Kirchmair J, Glen RC, Miranda E, Glatzel M, Galliciotti G. G392E neuroserpin causing the dementia FENIB is secreted from cells but is not synaptotoxic. Sci Rep 2021; 11:8766. [PMID: 33888787 PMCID: PMC8062559 DOI: 10.1038/s41598-021-88090-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/06/2021] [Indexed: 12/21/2022] Open
Abstract
Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a progressive neurodegenerative disease caused by point mutations in the gene for neuroserpin, a serine protease inhibitor of the nervous system. Different mutations are known that are responsible for mutant neuroserpin polymerization and accumulation as inclusion bodies in many cortical and subcortical neurons, thereby leading to cell death, dementia and epilepsy. Many efforts have been undertaken to elucidate the molecular pathways responsible for neuronal death. Most investigations have concentrated on analysis of intracellular mechanisms such as endoplasmic reticulum (ER) stress, ER-associated protein degradation (ERAD) and oxidative stress. We have generated a HEK-293 cell model of FENIB by overexpressing G392E-mutant neuroserpin and in this study we examine trafficking and toxicity of this polymerogenic variant. We observed that a small fraction of mutant neuroserpin is secreted via the ER-to-Golgi pathway, and that this release can be pharmacologically regulated. Overexpression of the mutant form of neuroserpin did not stimulate cell death in the HEK-293 cell model. Finally, when treating primary hippocampal neurons with G392E neuroserpin polymers, we did not detect cytotoxicity or synaptotoxicity. Altogether, we report here that a polymerogenic mutant form of neuroserpin is secreted from cells but is not toxic in the extracellular milieu.
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Affiliation(s)
- Thies Ingwersen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Linnenberg
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Emanuela D'Acunto
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy
| | - Shabnam Temori
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Irene Paolucci
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - David Wasilewski
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Behnam Mohammadi
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Johannes Kirchmair
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, UK
- Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Robert C Glen
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Cambridge, UK
- Division of Systems Medicine, Department of Metabolism Digestion and Reproduction, Imperial College London, London, UK
| | - Elena Miranda
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Rome, Italy
- Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Giovanna Galliciotti
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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15
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Wang Y, Wang C, Ranefall P, Broussard GJ, Wang Y, Shi G, Lyu B, Wu CT, Wang Y, Tian L, Yu G. SynQuant: an automatic tool to quantify synapses from microscopy images. Bioinformatics 2020; 36:1599-1606. [PMID: 31596456 DOI: 10.1093/bioinformatics/btz760] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/25/2019] [Accepted: 10/03/2019] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION Synapses are essential to neural signal transmission. Therefore, quantification of synapses and related neurites from images is vital to gain insights into the underlying pathways of brain functionality and diseases. Despite the wide availability of synaptic punctum imaging data, several issues are impeding satisfactory quantification of these structures by current tools. First, the antibodies used for labeling synapses are not perfectly specific to synapses. These antibodies may exist in neurites or other cell compartments. Second, the brightness of different neurites and synaptic puncta is heterogeneous due to the variation of antibody concentration and synapse-intrinsic differences. Third, images often have low signal to noise ratio due to constraints of experiment facilities and availability of sensitive antibodies. These issues make the detection of synapses challenging and necessitates developing a new tool to easily and accurately quantify synapses. RESULTS We present an automatic probability-principled synapse detection algorithm and integrate it into our synapse quantification tool SynQuant. Derived from the theory of order statistics, our method controls the false discovery rate and improves the power of detecting synapses. SynQuant is unsupervised, works for both 2D and 3D data, and can handle multiple staining channels. Through extensive experiments on one synthetic and three real datasets with ground truth annotation or manually labeling, SynQuant was demonstrated to outperform peer specialized unsupervised synapse detection tools as well as generic spot detection methods. AVAILABILITY AND IMPLEMENTATION Java source code, Fiji plug-in, and test data are available at https://github.com/yu-lab-vt/SynQuant. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Yizhi Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Congchao Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Petter Ranefall
- Centre for Image Analysis and SciLifeLab, Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Gerard Joey Broussard
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Yinxue Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Guilai Shi
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Boyu Lyu
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Chiung-Ting Wu
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Yue Wang
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Guoqiang Yu
- Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 22203, USA
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16
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Brucato FH, Benjamin DE. Synaptic Pruning in Alzheimer's Disease: Role of the Complement System. GLOBAL JOURNAL OF MEDICAL RESEARCH 2020; 20:10.34257/gjmrfvol20is6pg1. [PMID: 32982106 PMCID: PMC7518506 DOI: 10.34257/gjmrfvol20is6pg1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alz heimer’s disease (AD) continues to threaten aged individuals and health care systems around the world. Human beings have been trying to postpone, reduce, or eliminate the primary risk factor for AD, aging, throughout history. Despite this, there is currently only symptomatic treatment for AD and this treatment is limited to only a handful of FDA approved AD drugs.
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Affiliation(s)
- Frederic H Brucato
- Cascade Biotechnology Inc., Princeton Corporate Plaza 1 Deer Park Dr., Suite D5. Monmouth Junction NJ 08852
| | - Daniel E Benjamin
- Cascade Biotechnology Inc., Princeton Corporate Plaza 1 Deer Park Dr., Suite D5. Monmouth Junction NJ 08852
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17
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Mohammadi B, Linsenmeier L, Shafiq M, Puig B, Galliciotti G, Giudici C, Willem M, Eden T, Koch-Nolte F, Lin YH, Tatzelt J, Glatzel M, Altmeppen HC. Transgenic Overexpression of the Disordered Prion Protein N1 Fragment in Mice Does Not Protect Against Neurodegenerative Diseases Due to Impaired ER Translocation. Mol Neurobiol 2020; 57:2812-2829. [PMID: 32367491 PMCID: PMC7253391 DOI: 10.1007/s12035-020-01917-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 04/07/2020] [Indexed: 12/14/2022]
Abstract
The structurally disordered N-terminal half of the prion protein (PrPC) is constitutively released into the extracellular space by an endogenous proteolytic cleavage event. Once liberated, this N1 fragment acts neuroprotective in ischemic conditions and interferes with toxic peptides associated with neurodegenerative diseases, such as amyloid-beta (Aβ) in Alzheimer’s disease. Since analog protective effects of N1 in prion diseases, such as Creutzfeldt-Jakob disease, have not been studied, and given that the protease releasing N1 has not been identified to date, we have generated and characterized transgenic mice overexpressing N1 (TgN1). Upon intracerebral inoculation of TgN1 mice with prions, no protective effects were observed at the levels of survival, clinical course, neuropathological, or molecular assessment. Likewise, primary neurons of these mice did not show protection against Aβ toxicity. Our biochemical and morphological analyses revealed that this lack of protective effects is seemingly due to an impaired ER translocation of the disordered N1 resulting in its cytosolic retention with an uncleaved signal peptide. Thus, TgN1 mice represent the first animal model to prove the inefficient ER translocation of intrinsically disordered domains (IDD). In contrast to earlier studies, our data challenge roles of cytoplasmic N1 as a cell penetrating peptide or as a potent “anti-prion” agent. Lastly, our study highlights both the importance of structured domains in the nascent chain for proteins to be translocated and aspects to be considered when devising novel N1-based therapeutic approaches against neurodegenerative diseases.
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Affiliation(s)
- Behnam Mohammadi
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Luise Linsenmeier
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Mohsin Shafiq
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Berta Puig
- Department of Neurology, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Giovanna Galliciotti
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Camilla Giudici
- Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Michael Willem
- Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Thomas Eden
- Institute of Immunology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Yu-Hsuan Lin
- Institute of Biochemistry and Pathobiochemistry, Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, Bochum, Germany
| | - Jörg Tatzelt
- Institute of Biochemistry and Pathobiochemistry, Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, Bochum, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Hermann C Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
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18
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Shin SM, Skaar S, Danielson E, Lee SH. Aberrant expression of S-SCAM causes the loss of GABAergic synapses in hippocampal neurons. Sci Rep 2020; 10:83. [PMID: 31919468 PMCID: PMC6952429 DOI: 10.1038/s41598-019-57053-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/19/2019] [Indexed: 02/07/2023] Open
Abstract
The duplication and deletion mutations of the S-SCAM/MAGI-2 gene are associated with schizophrenia and infantile spasms, respectively. S-SCAM is a unique synaptic scaffolding protein that localizes to both excitatory and GABAergic synapses. However, consequences of aberrant S-SCAM expression on GABAergic synapses is little studied. Here we report the effect of S-SCAM knockdown and overexpression on GABAergic synapses. S-SCAM knockdown in cultured hippocampal neurons caused a drastic loss of both pre- and post-synaptic components of GABAergic synapses, indicating its essential role in GABAergic synapse formation and maintenance. Surprisingly, S-SCAM overexpression also attenuated GABAergic synapses, but the effect is mediated by the loss of postsynaptic GABAA receptors, gephyrin, and neuroligin 2 and does not involve presynaptic component vesicular GABA transporters. Overexpression studies using S-SCAM mutants with various domain deletions indicated that GABAergic synapse loss correlates with their ability to increase excitatory synaptic function. Consistently, AMPA receptor antagonist CNQX or calcineurin inhibitor FK506 abolished the S-SCAM overexpression-induced loss of GABAA receptors, supporting that GABAergic synapse loss by S-SCAM overexpression is due to the activity-induced dispersal of synaptic GABAA receptors. These results suggest that abnormal S-SCAM protein levels disrupt excitation/inhibition balance in neurons, which may explain the pathogenic nature of S-SCAM copy number variations.
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Affiliation(s)
- Seung Min Shin
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, USA
| | - Samantha Skaar
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, USA
| | - Eric Danielson
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, USA
| | - Sang H Lee
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, USA. .,Neuroscience Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin, USA.
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19
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Martineau FS, Sahu S, Plantier V, Buhler E, Schaller F, Fournier L, Chazal G, Kawasaki H, Represa A, Watrin F, Manent JB. Correct Laminar Positioning in the Neocortex Influences Proper Dendritic and Synaptic Development. Cereb Cortex 2019; 28:2976-2990. [PMID: 29788228 PMCID: PMC6041803 DOI: 10.1093/cercor/bhy113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Indexed: 01/28/2023] Open
Abstract
The neocortex is a 6-layered laminated structure with a precise anatomical and functional organization ensuring proper function. Laminar positioning of cortical neurons, as determined by termination of neuronal migration, is a key determinant of their ability to assemble into functional circuits. However, the exact contribution of laminar placement to dendrite morphogenesis and synapse formation remains unclear. Here we manipulated the laminar position of cortical neurons by knocking down doublecortin (Dcx), a crucial effector of migration, and show that misplaced neurons fail to properly form dendrites, spines, and functional glutamatergic and GABAergic synapses. We further show that knocking down Dcx in properly positioned neurons induces similar but milder defects, suggesting that the laminar misplacement is the primary cause of altered neuronal development. Thus, the specific laminar environment of their fated layers is crucial for the maturation of cortical neurons, and influences their functional integration into developing cortical circuits.
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Affiliation(s)
| | - Surajit Sahu
- INMED, Aix-Marseille University, INSERM U901, Marseille, France
| | | | | | | | | | | | - Hiroshi Kawasaki
- Department of Medical Neuroscience, Graduate School of Medical Sciences, Kanazawa University, Ishikawa, Japan
| | - Alfonso Represa
- INMED, Aix-Marseille University, INSERM U901, Marseille, France
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20
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Automated Macro Approach to Quantify Synapse Density in 2D Confocal Images from Fixed Immunolabeled Neural Tissue Sections. Methods Mol Biol 2019. [PMID: 31432476 DOI: 10.1007/978-1-4939-9686-5_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
This chapter describes an ImageJ/Fiji automated macro approach to estimate synapse densities in 2D fluorescence confocal microscopy images. The main step-by-step imaging workflow is explained, including example macro language scripts that perform all steps automatically for multiple images. Such tool provides a straightforward method for exploratory synapse screenings where hundreds to thousands of images need to be analyzed in order to render significant statistical information. The method can be adapted to any particular set of images where fixed brain slices have been immunolabeled against validated presynaptic and postsynaptic markers.
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21
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Moosecker S, Gomes P, Dioli C, Yu S, Sotiropoulos I, Almeida OFX. Activated PPARγ Abrogates Misprocessing of Amyloid Precursor Protein, Tau Missorting and Synaptotoxicity. Front Cell Neurosci 2019; 13:239. [PMID: 31263400 PMCID: PMC6584807 DOI: 10.3389/fncel.2019.00239] [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: 01/07/2019] [Accepted: 05/13/2019] [Indexed: 11/20/2022] Open
Abstract
Type 2 diabetes increases the risk for dementia, including Alzheimer’s disease (AD). Pioglitazone (Pio), a pharmacological agonist of the peroxisome proliferator-activated receptor γ (PPARγ), improves insulin sensitivity and has been suggested to have potential in the management of AD symptoms, albeit through mostly unknown mechanisms. We here investigated the potential of Pio to counter synaptic malfunction and loss, a characteristic of AD pathology and its accompanying cognitive deficits. Results from experiments on primary mouse neuronal cultures and a human neural cell line (SH-SY5Y) show that Pio treatment attenuates amyloid β (Aβ)-triggered the pathological (mis-) processing of amyloid precursor protein (APP) and inhibits Aβ-induced accumulation and hyperphosphorylation of Tau. These events are accompanied by increased glutamatergic receptor 2B subunit (GluN2B) levels that are causally linked with neuronal death. Further, Pio treatment blocks Aβ-triggered missorting of hyperphosphorylated Tau to synapses and the subsequent loss of PSD95-positive synapses. These latter effects of Pio are PPARγ-mediated since they are blocked in the presence of GW9662, a selective PPARγ inhibitor. Collectively, these data show that activated PPARγ buffer neurons against APP misprocessing, Tau hyperphosphorylation and its missorting to synapses and subsequently, synaptic loss. These first insights into the mechanisms through which PPARγ influences synaptic loss make a case for further exploration of the potential usefulness of PPARγ agonists in the prevention and treatment of synaptic pathology in AD.
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Affiliation(s)
- Susanne Moosecker
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Patrícia Gomes
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Guimarães, Portugal
| | - Chrysoula Dioli
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Guimarães, Portugal
| | - Shuang Yu
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Ioannis Sotiropoulos
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Guimarães, Portugal
| | - Osborne F X Almeida
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
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22
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Sellgren CM, Gracias J, Watmuff B, Biag JD, Thanos JM, Whittredge PB, Fu T, Worringer K, Brown HE, Wang J, Kaykas A, Karmacharya R, Goold CP, Sheridan SD, Perlis RH. Increased synapse elimination by microglia in schizophrenia patient-derived models of synaptic pruning. Nat Neurosci 2019; 22:374-385. [PMID: 30718903 DOI: 10.1038/s41593-018-0334-7] [Citation(s) in RCA: 424] [Impact Index Per Article: 84.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/19/2018] [Indexed: 12/11/2022]
Abstract
Synapse density is reduced in postmortem cortical tissue from schizophrenia patients, which is suggestive of increased synapse elimination. Using a reprogrammed in vitro model of microglia-mediated synapse engulfment, we demonstrate increased synapse elimination in patient-derived neural cultures and isolated synaptosomes. This excessive synaptic pruning reflects abnormalities in both microglia-like cells and synaptic structures. Further, we find that schizophrenia risk-associated variants within the human complement component 4 locus are associated with increased neuronal complement deposition and synapse uptake; however, they do not fully explain the observed increase in synapse uptake. Finally, we demonstrate that the antibiotic minocycline reduces microglia-mediated synapse uptake in vitro and its use is associated with a modest decrease in incident schizophrenia risk compared to other antibiotics in a cohort of young adults drawn from electronic health records. These findings point to excessive pruning as a potential target for delaying or preventing the onset of schizophrenia in high-risk individuals.
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Affiliation(s)
- Carl M Sellgren
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA. .,Department of Psychiatry, Harvard Medical School, Boston, MA, USA. .,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Jessica Gracias
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Bradley Watmuff
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jonathan D Biag
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Jessica M Thanos
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | | | - Ting Fu
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | | | - Hannah E Brown
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jennifer Wang
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Ajamete Kaykas
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Rakesh Karmacharya
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.,Schizophrenia and Bipolar Disorder Program, McLean Hospital, Belmont, MA, USA
| | | | - Steven D Sheridan
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Roy H Perlis
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA. .,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
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Ha HTT, Leal-Ortiz S, Lalwani K, Kiyonaka S, Hamachi I, Mysore SP, Montgomery JM, Garner CC, Huguenard JR, Kim SA. Shank and Zinc Mediate an AMPA Receptor Subunit Switch in Developing Neurons. Front Mol Neurosci 2018; 11:405. [PMID: 30524232 PMCID: PMC6256285 DOI: 10.3389/fnmol.2018.00405] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/15/2018] [Indexed: 11/18/2022] Open
Abstract
During development, pyramidal neurons undergo dynamic regulation of AMPA receptor (AMPAR) subunit composition and density to help drive synaptic plasticity and maturation. These normal developmental changes in AMPARs are particularly vulnerable to risk factors for Autism Spectrum Disorders (ASDs), which include loss or mutations of synaptic proteins and environmental insults, such as dietary zinc deficiency. Here, we show how Shank2 and Shank3 mediate a zinc-dependent regulation of AMPAR function and subunit switch from GluA2-lacking to GluA2-containing AMPARs. Over development, we found a concomitant increase in Shank2 and Shank3 with GluA2 at synapses, implicating these molecules as potential players in AMPAR maturation. Since Shank activation and function require zinc, we next studied whether neuronal activity regulated postsynaptic zinc at glutamatergic synapses. Zinc was found to increase transiently and reversibly with neuronal depolarization at synapses, which could affect Shank and AMPAR localization and activity. Elevated zinc induced multiple functional changes in AMPAR, indicative of a subunit switch. Specifically, zinc lengthened the decay time of AMPAR-mediated synaptic currents and reduced their inward rectification in young hippocampal neurons. Mechanistically, both Shank2 and Shank3 were necessary for the zinc-sensitive enhancement of AMPAR-mediated synaptic transmission and act in concert to promote removal of GluA1 while enhancing recruitment of GluA2 at pre-existing Shank puncta. These findings highlight a cooperative local dynamic regulation of AMPAR subunit switch controlled by zinc signaling through Shank2 and Shank3 to shape the biophysical properties of developing glutamatergic synapses. Given the zinc sensitivity of young neurons and its dependence on Shank2 and Shank3, genetic mutations and/or environmental insults during early development could impair synaptic maturation and circuit formation that underlie ASD etiology.
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Affiliation(s)
- Huong T T Ha
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States.,Neurosciences Graduate Program, School of Medicine, Stanford University, Stanford, CA, United States
| | - Sergio Leal-Ortiz
- Department of Material Science & Engineering, School of Engineering, Stanford University, Stanford, CA, United States
| | - Kriti Lalwani
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
| | - Shigeki Kiyonaka
- Department of Synthetic Chemistry & Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Itaru Hamachi
- Department of Synthetic Chemistry & Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Shreesh P Mysore
- Department of Psychological & Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Craig C Garner
- German Center for Neurodegenerative Diseases (DZNE), Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - John R Huguenard
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
| | - Sally A Kim
- Department of Neurology & Neurological Sciences, School of Medicine, Stanford University, Stanford, CA, United States
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24
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Reciprocal control of excitatory synapse numbers by Wnt and Wnt inhibitor PRR7 secreted on exosomes. Nat Commun 2018; 9:3434. [PMID: 30143647 PMCID: PMC6109165 DOI: 10.1038/s41467-018-05858-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 07/25/2018] [Indexed: 12/22/2022] Open
Abstract
Secreted Wnts play crucial roles in synaptogenesis and synapse maintenance, but endogenous factors promoting synapse elimination in central neurons remain unknown. Here we show that proline-rich 7 (PRR7) induces specific removal of excitatory synapses and acts as a Wnt inhibitor. Remarkably, transmembrane protein PRR7 is activity-dependently released by neurons via exosomes. Exosomal PRR7 is uptaken by neurons through membrane fusion and eliminates excitatory synapses in neighboring neurons. Conversely, PRR7 knockdown in sparse neurons greatly increases excitatory synapse numbers in all surrounding neurons. These non-cell autonomous effects of PRR7 are effectively negated by augmentation or blockade of Wnt signaling. PRR7 exerts its effect by blocking the exosomal secretion of Wnts, activation of GSK3β, and promoting proteasomal degradation of PSD proteins. These data uncover a proximity-dependent, reciprocal mechanism for the regulation of excitatory synapse numbers in local neurons and demonstrate the significance of exosomes in inter-neuronal signaling in the vertebrate brain. Wnts are important for synapse formation and maintenance. Here, the authors show that proline-rich 7 (PRR7) is a Wnt inhibitor that is secreted via exosomes to regulate excitatory synapse numbers.
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25
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He HY, Shen W, Zheng L, Guo X, Cline HT. Excitatory synaptic dysfunction cell-autonomously decreases inhibitory inputs and disrupts structural and functional plasticity. Nat Commun 2018; 9:2893. [PMID: 30042473 PMCID: PMC6057951 DOI: 10.1038/s41467-018-05125-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 06/08/2018] [Indexed: 12/23/2022] Open
Abstract
Functional circuit assembly is thought to require coordinated development of excitation and inhibition, but whether they are co-regulated cell-autonomously remains unclear. We investigate effects of decreased glutamatergic synaptic input on inhibitory synapses by expressing AMPAR subunit, GluA1 and GluA2, C-terminal peptides (GluA1CTP and GluA2CTP) in developing Xenopus tectal neurons. GluACTPs decrease excitatory synaptic inputs and cell-autonomously decreases inhibitory synaptic inputs in excitatory and inhibitory neurons. Visually evoked excitatory and inhibitory currents decrease proportionately, maintaining excitation/inhibition. GluACTPs affect dendrite structure and visual experience-dependent structural plasticity differently in excitatory and inhibitory neurons. Deficits in excitatory and inhibitory synaptic transmission and experience-dependent plasticity manifest in altered visual receptive field properties. Both visual avoidance behavior and learning-induced behavioral plasticity are impaired, suggesting that maintaining excitation/inhibition alone is insufficient to preserve circuit function. We demonstrate that excitatory synaptic dysfunction in individual neurons cell-autonomously decreases inhibitory inputs and disrupts neuronal and circuit plasticity, information processing and learning. Both inhibitory and excitatory input development are shaped by activity, but one may be dependent on the other. Here, the authors examine plasticity of inhibitory inputs in vivo, as well as behavioral consequences in tadpoles where excitatory transmission has been impaired.
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Affiliation(s)
- Hai-Yan He
- The Dorris Neuroscience Center, Department of Neuroscience, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Wanhua Shen
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 310036, China.
| | - Lijun Zheng
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 310036, China
| | - Xia Guo
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 310036, China
| | - Hollis T Cline
- The Dorris Neuroscience Center, Department of Neuroscience, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
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26
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Verstraelen P, Van Dyck M, Verschuuren M, Kashikar ND, Nuydens R, Timmermans JP, De Vos WH. Image-Based Profiling of Synaptic Connectivity in Primary Neuronal Cell Culture. Front Neurosci 2018; 12:389. [PMID: 29997468 PMCID: PMC6028601 DOI: 10.3389/fnins.2018.00389] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/22/2018] [Indexed: 12/04/2022] Open
Abstract
Neurological disorders display a broad spectrum of clinical manifestations. Yet, at the cellular level, virtually all these diseases converge into a common phenotype of dysregulated synaptic connectivity. In dementia, synapse dysfunction precedes neurodegeneration and cognitive impairment by several years, making the synapse a crucial entry point for the development of diagnostic and therapeutic strategies. Whereas high-resolution imaging and biochemical fractionations yield detailed insight into the molecular composition of the synapse, standardized assays are required to quickly gauge synaptic connectivity across large populations of cells under a variety of experimental conditions. Such screening capabilities have now become widely accessible with the advent of high-throughput, high-content microscopy. In this review, we discuss how microscopy-based approaches can be used to extract quantitative information about synaptic connectivity in primary neurons with deep coverage. We elaborate on microscopic readouts that may serve as a proxy for morphofunctional connectivity and we critically analyze their merits and limitations. Finally, we allude to the potential of alternative culture paradigms and integrative approaches to enable comprehensive profiling of synaptic connectivity.
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Affiliation(s)
- Peter Verstraelen
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Michiel Van Dyck
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Marlies Verschuuren
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | | | - Rony Nuydens
- Janssen Research and Development, Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Winnok H. De Vos
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
- Cell Systems and Imaging, Department of Molecular Biotechnology, Ghent University, Ghent, Belgium
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27
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Varando G, Benavides-Piccione R, Muñoz A, Kastanauskaite A, Bielza C, Larrañaga P, DeFelipe J. MultiMap: A Tool to Automatically Extract and Analyse Spatial Microscopic Data From Large Stacks of Confocal Microscopy Images. Front Neuroanat 2018; 12:37. [PMID: 29875639 PMCID: PMC5974206 DOI: 10.3389/fnana.2018.00037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/24/2018] [Indexed: 11/13/2022] Open
Abstract
The development of 3D visualization and reconstruction methods to analyse microscopic structures at different levels of resolutions is of great importance to define brain microorganization and connectivity. MultiMap is a new tool that allows the visualization, 3D segmentation and quantification of fluorescent structures selectively in the neuropil from large stacks of confocal microscopy images. The major contribution of this tool is the posibility to easily navigate and create regions of interest of any shape and size within a large brain area that will be automatically 3D segmented and quantified to determine the density of puncta in the neuropil. As a proof of concept, we focused on the analysis of glutamatergic and GABAergic presynaptic axon terminals in the mouse hippocampal region to demonstrate its use as a tool to provide putative excitatory and inhibitory synaptic maps. The segmentation and quantification method has been validated over expert labeled images of the mouse hippocampus and over two benchmark datasets, obtaining comparable results to the expert detections.
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Affiliation(s)
- Gherardo Varando
- Computational Intelligence Group, Department of Artificial Intelligence, Universidad Politécnica de Madrid, Madrid, Spain
| | - Ruth Benavides-Piccione
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
| | - Alberto Muñoz
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain.,Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Asta Kastanauskaite
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
| | - Concha Bielza
- Computational Intelligence Group, Department of Artificial Intelligence, Universidad Politécnica de Madrid, Madrid, Spain
| | - Pedro Larrañaga
- Computational Intelligence Group, Department of Artificial Intelligence, Universidad Politécnica de Madrid, Madrid, Spain
| | - Javier DeFelipe
- Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal (CSIC), Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
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28
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Li Y, Chang L, Song Y, Gao X, Roselli F, Liu J, Zhou W, Fang Y, Ling W, Li H, Almeida OFX, Wu Y. Astrocytic GluN2A and GluN2B Oppose the Synaptotoxic Effects of Amyloid-β1-40 in Hippocampal Cells. J Alzheimers Dis 2018; 54:135-48. [PMID: 27497478 DOI: 10.3233/jad-160297] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Early-stage Alzheimer's disease (AD) is characterized by synaptic dysfunction, a phenomenon in which soluble oligomers of amyloid-beta (Aβ) and N-methyl-D-aspartate receptor (NMDAR) are implicated. Here, we demonstrated that astrocytes express NMDARs and therefore have the potential to modulate the synaptotoxic actions of Aβ. We found that specific pharmacological antagonism of two of the major NMDAR subunits, GluN2A and GluN2B, exacerbates Aβ-induced synaptotoxicity suggesting, for the first time, that astrocytic GluN2A and GluN2B mediate synaptoprotection. From the perspective of the pathogenic mechanisms of Alzheimer's disease, in which Aβ and NMDAR play significant roles, these observations are striking since neuronal GluN2A and GluN2B are well known modulators of neurodegeneration. We did initial studies to understand the basis for the differential effects of astrocytic and neuronal GluN2A and GluN2B in the promotion of synapse survival, and identified a neurotrophin produced by astrocytes, nerve growth factor β (β-NGF), as a likely mediator of the synaptoprotective effects of astrocytic GluN2A and GluN2B activation. The results presented suggest that astrocytes may be suitable druggable targets for the prevention and/or delay of the synaptic loss that occurs during early stages of AD.
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Affiliation(s)
- Yan Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Lirong Chang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Xianghong Gao
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Francesco Roselli
- Departments of Neurology and Anatomy, University of Ulm School of Medicine, Germany.,Max Planck Institute of Psychiatry, Munich, Germany
| | - Jinping Liu
- School of Medicine, Tsinghua University, Beijing, China
| | - Wei Zhou
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuan Fang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Wei Ling
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Hui Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | | | - Yan Wu
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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29
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Patterson KR, Dalmau J, Lancaster E. Mechanisms of Caspr2 antibodies in autoimmune encephalitis and neuromyotonia. Ann Neurol 2018; 83:40-51. [PMID: 29244234 PMCID: PMC5876120 DOI: 10.1002/ana.25120] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To determine the pathogenic mechanisms of autoantibodies to the cell adhesion molecule Caspr2 in acquired neuromyotonia and autoimmune encephalitis. METHODS Caspr2-positive samples were confirmed using a cell-based assay, and their IgG subtypes were determined by enzyme-linked immunosorbent assay and cell-based assay. A solid phase binding assay quantified the binding of Caspr2 to contactin-2 in the presence of Caspr2 autoantibodies. Living cultures of primary rat hippocampal neurons were incubated with Caspr2-positive or control sera, and the distribution of Caspr2-positive immunofluorescent puncta and total surface Caspr2 was quantified. HEK cells transfected to express Caspr2 were incubated with Caspr2-positive or control samples, and cell-surface biotinylation and Western blot were used to assess total, internalized, and surface levels of Caspr2. RESULTS We confirmed 6 samples with strong Caspr2 reactivity. IgG4 Caspr2 antibodies were present in all 6 cases. Caspr2 interacted with another cell adhesion molecule, contactin-2, with nanomolar affinity in the solid phase assay, and Caspr2 autoantibodies inhibited this interaction. Caspr2 autoantibodies did not affect the surface expression of Caspr2 in rat primary hippocampal neurons or transfected HEK cells. INTERPRETATION Caspr2 autoantibodies inhibit the interaction of Caspr2 with contactin-2 but do not cause internalization of Caspr2. Functional blocking of cell adhesion molecule interactions represents a potential mechanism with therapeutic implications for IgG4 autoantibodies to cell adhesion molecules in neurological diseases. Ann Neurol 2018;83:40-51.
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Affiliation(s)
- Kristina R Patterson
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Josep Dalmau
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA
- Hospital Clinic-August Pi i Sunyer Biomedical Research Institute (IDIBAPS), University of Barcelona, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies Barcelona, Spain
| | - Eric Lancaster
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA
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30
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Mortal S, Iseppon F, Perissinotto A, D'Este E, Cojoc D, Napolitano LMR, Torre V. Actin Waves Do Not Boost Neurite Outgrowth in the Early Stages of Neuron Maturation. Front Cell Neurosci 2017; 11:402. [PMID: 29326552 PMCID: PMC5741660 DOI: 10.3389/fncel.2017.00402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/01/2017] [Indexed: 11/27/2022] Open
Abstract
During neurite development, Actin Waves (AWs) emerge at the neurite base and move up to its tip, causing a transient retraction of the Growth Cone (GC). Many studies have shown that AWs are linked to outbursts of neurite growth and, therefore, contribute to the fast elongation of the nascent axon. Using long term live cell-imaging, we show that AWs do not boost neurite outgrowth and that neurites without AWs can elongate for several hundred microns. Inhibition of Myosin II abolishes the transient GC retraction and strongly modifies the AWs morphology. Super-resolution nanoscopy shows that Myosin IIB shapes the growth cone-like AWs structure and is differently distributed in AWs and GCs. Interestingly, depletion of membrane cholesterol and inhibition of Rho GTPases decrease AWs frequency and velocity. Our results indicate that Myosin IIB, membrane tension, and small Rho GTPases are important players in the regulation of the AW dynamics. Finally, we suggest a role for AWs in maintaining the GCs active during environmental exploration.
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Affiliation(s)
- Simone Mortal
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Federico Iseppon
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Andrea Perissinotto
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Elisa D'Este
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dan Cojoc
- Optical Manipulation Lab, Istituto Officina dei Materiali (CNR), Trieste, Italy
| | - Luisa M R Napolitano
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
| | - Vincent Torre
- Neurobiology Department, International School for Advanced Studies, Trieste, Italy
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Intellicount: High-Throughput Quantification of Fluorescent Synaptic Protein Puncta by Machine Learning. eNeuro 2017; 4:eN-MNT-0219-17. [PMID: 29218324 PMCID: PMC5718246 DOI: 10.1523/eneuro.0219-17.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/18/2017] [Accepted: 11/06/2017] [Indexed: 01/07/2023] Open
Abstract
Synapse formation analyses can be performed by imaging and quantifying fluorescent signals of synaptic markers. Traditionally, these analyses are done using simple or multiple thresholding and segmentation approaches or by labor-intensive manual analysis by a human observer. Here, we describe Intellicount, a high-throughput, fully-automated synapse quantification program which applies a novel machine learning (ML)-based image processing algorithm to systematically improve region of interest (ROI) identification over simple thresholding techniques. Through processing large datasets from both human and mouse neurons, we demonstrate that this approach allows image processing to proceed independently of carefully set thresholds, thus reducing the need for human intervention. As a result, this method can efficiently and accurately process large image datasets with minimal interaction by the experimenter, making it less prone to bias and less liable to human error. Furthermore, Intellicount is integrated into an intuitive graphical user interface (GUI) that provides a set of valuable features, including automated and multifunctional figure generation, routine statistical analyses, and the ability to run full datasets through nested folders, greatly expediting the data analysis process.
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Sugie A, Möhl C, Hakeda-Suzuki S, Matsui H, Suzuki T, Tavosanis G. Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light. J Vis Exp 2017. [PMID: 28287587 DOI: 10.3791/55176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at the synaptic level. The Active Zone (AZ) is the region at the presynaptic membrane that mediates neurotransmitter release and is composed of a dense collection of scaffold proteins. AZs of Drosophila melanogaster (Drosophila) photoreceptors undergo molecular remodeling after prolonged exposure to natural ambient light. Thus the level of neuronal activity can rearrange the molecular composition of the AZ and contribute to the regulation of the functional output. Starting from the light exposure set-up preparation to the immunohistochemistry, this protocol details how to quantify the number, the spatial distribution, and the delocalization level of synaptic molecules at AZs in Drosophila photoreceptors. Using image analysis software, clusters of the GFP-fused AZ component Bruchpilot were identified for each R8 photoreceptor (R8) axon terminal. Detected Bruchpilot spots were automatically assigned to individual R8 axons. To calculate the distribution of spot frequency along the axon, we implemented a customized software plugin. Each axon's start-point and end-point were manually defined and the position of each Bruchpilot spot was projected onto the connecting line between start and end-point. Besides the number of Bruchpilot clusters, we also quantified the delocalization level of Bruchpilot-GFP within the clusters. These measurements reflect in detail the spatially resolved synaptic dynamics in a single neuron under different environmental conditions to stimuli.
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Affiliation(s)
- Atsushi Sugie
- Department of Neuroscience of Disease, Center for Transdisciplinary Research, Niigata University; Brain Research Institute, Niigata University; Dendrite Differentiation, German Center for Neurodegenerative Diseases (DZNE);
| | - Christoph Möhl
- Image and Data Analysis Facility, German Center for Neurodegenerative Diseases (DZNE);
| | - Satoko Hakeda-Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology (Titech)
| | - Hideaki Matsui
- Department of Neuroscience of Disease, Center for Transdisciplinary Research, Niigata University; Brain Research Institute, Niigata University
| | - Takashi Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology (Titech)
| | - Gaia Tavosanis
- Dendrite Differentiation, German Center for Neurodegenerative Diseases (DZNE)
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Chang L, Zhang Y, Liu J, Song Y, Lv A, Li Y, Zhou W, Yan Z, Almeida OFX, Wu Y. Differential Regulation of N-Methyl-D-Aspartate Receptor Subunits is an Early Event in the Actions of Soluble Amyloid-β(1-40) Oligomers on Hippocampal Neurons. J Alzheimers Dis 2016; 51:197-212. [PMID: 26836185 DOI: 10.3233/jad-150942] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Synaptic dysfunction during early stages of Alzheimer's disease (AD) is triggered by soluble amyloid-β (Aβ) oligomers that interact with NMDA receptors (NMDARs). We previously showed that Aβ induces synaptic protein loss through NMDARs, albeit through undefined mechanisms. Accordingly, we here examined the contribution of individual NMDAR subunits to synaptotoxicity and demonstrate that Aβ exerts differential effects on the levels and distribution of GluN2A and GluN2B subunits of NMDAR in dendrites. Treatment of cultured hippocampal neurons with Aβ1-40 (10 μM, 1 h) induced a significant increase of dendritic and synaptic GluN2B puncta densities with parallel decreases in the puncta densities of denritic and synaptic pTyr1472-GluN2B. Conversely, Aβ significantly decreased dendritic and synaptic GluN2A and dendritic pTyr1325-GluN2A puncta densities and increased synaptic pTyr1325-GluN2A puncta densities. Unexpectedly, Aβ treatment resulted in a significant reduction of GluN2B and pTyr1472-GluN2B protein levels but did not influence GluN2A and pTyr1325-GluN2A levels. These results show that Aβ exerts complex and distinct regulatory effects on the trafficking and phosphorylation of GluN2A and GluN2B, as well as on their localization within synaptic and non-synaptic sites. Increased understanding of these early events in Aβ-induced synaptic dysfunction is likely to be important for the development of timely preventive and therapeutic interventions.
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Affiliation(s)
- Lirong Chang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yali Zhang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Jinping Liu
- School of Medicine, Tsinghua University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Angchu Lv
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yan Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Wei Zhou
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Zhen Yan
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY, USA
| | | | - Yan Wu
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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Zhou W, Chang L, Fang Y, Du Z, Li Y, Song Y, Hao F, Lv L, Wu Y. Cerebral dopamine neurotrophic factor alleviates Aβ 25-35 -induced endoplasmic reticulum stress and early synaptotoxicity in rat hippocampal cells. Neurosci Lett 2016; 633:40-46. [DOI: 10.1016/j.neulet.2016.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 09/01/2016] [Accepted: 09/07/2016] [Indexed: 10/21/2022]
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Galati DF, Hiester BG, Jones KR. Computer Simulations Support a Morphological Contribution to BDNF Enhancement of Action Potential Generation. Front Cell Neurosci 2016; 10:209. [PMID: 27683544 PMCID: PMC5021759 DOI: 10.3389/fncel.2016.00209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/22/2016] [Indexed: 01/10/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) regulates both action potential (AP) generation and neuron morphology. However, whether BDNF-induced changes in neuron morphology directly impact AP generation is unclear. We quantified BDNF’s effect on cultured cortical neuron morphological parameters and found that BDNF stimulates dendrite growth and addition of dendrites while increasing both excitatory and inhibitory presynaptic inputs in a spatially restricted manner. To gain insight into how these combined changes in neuron structure and synaptic input impact AP generation, we used the morphological parameters we gathered to generate computational models. Simulations suggest that BDNF-induced neuron morphologies generate more APs under a wide variety of conditions. Synapse and dendrite addition have the greatest impact on AP generation. However, subtle alterations in excitatory/inhibitory synapse ratio and strength have a significant impact on AP generation when synaptic activity is low. Consistent with these simulations, BDNF rapidly enhances spontaneous activity in cortical cultures. We propose that BDNF promotes neuron morphologies that are intrinsically more efficient at translating barrages of synaptic activity into APs, which is a previously unexplored aspect of BDNF’s function.
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Affiliation(s)
- Domenico F Galati
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder Boulder, CO, USA
| | - Brian G Hiester
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder Boulder, CO, USA
| | - Kevin R Jones
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder Boulder, CO, USA
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Belmer A, Klenowski PM, Patkar OL, Bartlett SE. Mapping the connectivity of serotonin transporter immunoreactive axons to excitatory and inhibitory neurochemical synapses in the mouse limbic brain. Brain Struct Funct 2016; 222:1297-1314. [PMID: 27485750 PMCID: PMC5368196 DOI: 10.1007/s00429-016-1278-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/20/2016] [Indexed: 12/25/2022]
Abstract
Serotonin neurons arise from the brainstem raphe nuclei and send their projections throughout the brain to release 5-HT which acts as a modulator of several neuronal populations. Previous electron microscopy studies in rats have morphologically determined the distribution of 5-HT release sites (boutons) in certain brain regions and have shown that 5-HT containing boutons form synaptic contacts that are either symmetric or asymmetric. In addition, 5-HT boutons can form synaptic triads with the pre- and postsynaptic specializations of either symmetrical or asymmetrical synapses. However, due to the labor intensive processing of serial sections required by electron microscopy, little is known about the neurochemical properties or the quantitative distribution of 5-HT triads within whole brain or discrete subregions. Therefore, we used a semi-automated approach that combines immunohistochemistry and high-resolution confocal microscopy to label serotonin transporter (SERT) immunoreactive axons and reconstruct in 3D their distribution within limbic brain regions. We also used antibodies against key pre- (synaptophysin) and postsynaptic components of excitatory (PSD95) or inhibitory (gephyrin) synapses to (1) identify putative 5-HTergic boutons within SERT immunoreactive axons and, (2) quantify their close apposition to neurochemical excitatory or inhibitory synapses. We provide a 5-HTergic axon density map and have determined the ratio of synaptic triads consisting of a 5-HT bouton in close proximity to either neurochemical excitatory or inhibitory synapses within different limbic brain areas. The ability to model and map changes in 5-HTergic axonal density and the formation of triadic connectivity within whole brain regions using this rapid and quantitative approach offers new possibilities for studying neuroplastic changes in the 5-HTergic pathway.
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Affiliation(s)
- Arnauld Belmer
- Translational Research Institute, Queensland University of Technology, Brisbane, Qld 4059, Australia
| | - Paul M Klenowski
- Translational Research Institute, Queensland University of Technology, Brisbane, Qld 4059, Australia
| | - Omkar L Patkar
- Translational Research Institute, Queensland University of Technology, Brisbane, Qld 4059, Australia
| | - Selena E Bartlett
- Translational Research Institute, Queensland University of Technology, Brisbane, Qld 4059, Australia. .,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia.
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Correction: SynPAnal: software for rapid quantification of the density and intensity of protein puncta from fluorescence microscopy images of neurons. PLoS One 2015; 10:e0118657. [PMID: 25742427 PMCID: PMC4351046 DOI: 10.1371/journal.pone.0118657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
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