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Huang S, Huang G. The utilization of quantum dot labeling as a burgeoning technique in the field of biological imaging. RSC Adv 2024; 14:20884-20897. [PMID: 38957578 PMCID: PMC11217725 DOI: 10.1039/d4ra04402a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024] Open
Abstract
Quantum dots (QDs), with their unique optical and physical properties, have revolutionized the field of biological imaging, providing researchers with tools to explore cellular processes and molecular interactions in unprecedented detail. This review explores the diverse properties of QDs, emphasizing their application in biological imaging and addressing both their advantages and challenges. We discuss the developments in QD technology that have facilitated their integration into bioimaging, highlighting the role of surface modifications in enhancing their biocompatibility and functionality. The varied applications of QDs in both in vitro and in vivo imaging settings are examined, showcasing their capacity to deliver brighter, more stable, and multiplexed imaging solutions compared to traditional fluorescent dyes. Furthermore, we delve into the challenges associated with QD use, particularly concerns regarding their potential toxicity and long-term effects on biological systems, and explore ongoing research aimed at mitigating these issues. Finally, we discuss future directions in QD technology, anticipating advancements that will further solidify their role in biological imaging and open up new avenues for scientific exploration.
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Affiliation(s)
- Shiyu Huang
- School of Chemistry and Chemical Engineering, Southwest University Chongqing 400700 China
- Key Laboratory of Carbohydrate Science and Engineering, Chongqing Normal University Chongqing 401331 China
| | - Gangliang Huang
- Key Laboratory of Carbohydrate Science and Engineering, Chongqing Normal University Chongqing 401331 China
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2
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Torres R, Thal LB, McBride JR, Cohen BE, Rosenthal SJ. Quantum Dot Fluorescent Imaging: Using Atomic Structure Correlation Studies to Improve Photophysical Properties. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:3632-3640. [PMID: 38476823 PMCID: PMC10926165 DOI: 10.1021/acs.jpcc.3c07367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/12/2024] [Accepted: 01/12/2024] [Indexed: 03/14/2024]
Abstract
Efforts to study intricate, higher-order cellular functions have called for fluorescence imaging under physiologically relevant conditions such as tissue systems in simulated native buffers. This endeavor has presented novel challenges for fluorescent probes initially designed for use in simple buffers and monolayer cell culture. Among current fluorescent probes, semiconductor nanocrystals, or quantum dots (QDs), offer superior photophysical properties that are the products of their nanoscale architectures and chemical formulations. While their high brightness and photostability are ideal for these biological environments, even state of the art QDs can struggle under certain physiological conditions. A recent method correlating electron microscopy ultrastructure with single-QD fluorescence has begun to highlight subtle structural defects in QDs once believed to have no significant impact on photoluminescence (PL). Specific defects, such as exposed core facets, have been shown to quench QD PL in physiologically accurate conditions. For QD-based imaging in complex cellular systems to be fully realized, mechanistic insight and structural optimization of size and PL should be established. Insight from single QD resolution atomic structure and photophysical correlative studies provides a direct course to synthetically tune QDs to match these challenging environments.
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Affiliation(s)
- Ruben Torres
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute of Chemical Biology, Vanderbilt
University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Lucas B. Thal
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute of Chemical Biology, Vanderbilt
University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - James R. McBride
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Bruce E. Cohen
- The
Molecular Foundry and Division of Molecular Biophysics & Integrated
Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sandra J. Rosenthal
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute of Chemical Biology, Vanderbilt
University, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Pharmacology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt
Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, Tennessee 37240, United States
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3
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Green MJ, Ge H, Flower SE, Pourzand C, Botchway SW, Wang HC, Kuganathan N, Kociok-Köhn G, Li M, Xu S, James TD, Pascu SI. Fluorescent naphthalimide boronates as theranostics: structural investigations, confocal fluorescence and multiphoton fluorescence lifetime imaging microscopy in living cells. RSC Chem Biol 2023; 4:1082-1095. [PMID: 38033726 PMCID: PMC10685793 DOI: 10.1039/d3cb00112a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/17/2023] [Indexed: 12/02/2023] Open
Abstract
New design and synthetic strategies were developed to generate functional phenyl boronic acid (BA)-based fluorescent probes incorporating the 1,8-naphthalimide (NI) tag. This fluorescent core was anchored onto the BA unit through small organic linkers consisting of nitrogen groups which can arrest, and internally stabilise the phenyl-boronate units. The newly synthesised fluorophores were characterised spectroscopically by NMR spectroscopy and mass spectrometry and evaluated for their ability to bind to a naturally occurring polysaccharide, β-d-glucan in DMSO and simultaneously as act as in vitro cell imaging reagents. The uptake of these new NI-boronic acid derivatives was studied living cancer cells (HeLa, PC-3) in the presence, and absence, of β-d-glucan. Time-correlated single-photon counting (TCSPC) of DMSO solutions and two-photon fluorescence-lifetime imaging microscopy (FLIM) techniques allowed an insight into the probes' interaction with their environment. Their cellular uptake and distributions were imaged using laser scanning confocal fluorescence microscopy under single- and two-photon excitation regimes (λmax 910 nm). FLIM facilitated the estimation of the impact of the probe's cellular surroundings using the fluorophore lifetime. The extent to which this was mediated by the β-d-glucan was visualised by 2-photon FLIM in living cells. The fluorescence lifetime observed under a range of temperatures varied appreciably, indicating that changes in the environment can be sensed by these probes. In all cases, the cellular membrane penetration of these new probes was remarkable even under variable temperature conditions and localisation was widely concentrated in the cellular cytoplasm, without specific organelle trapping: we conclude that these new probes show promise for cellular imaging in living cancer cells.
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Affiliation(s)
- Megan J Green
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
| | - Haobo Ge
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
| | - Stephen E Flower
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
| | - Charareh Pourzand
- Department of Life Sciences, University of Bath BA2 7AY UK
- Centre for Therapeutic Innovation, University of Bath BA2 7AY UK
| | - Stanley W Botchway
- STFC Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus Harwell Oxfordshire OX11 0QX UK
| | - Hui-Chen Wang
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
| | | | - Gabriele Kociok-Köhn
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
- Materials and Chemical Characterisation Facility (MC2), University of Bath Calverton Down Bath BA2 7AY UK
| | - Meng Li
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology Beijing 100029 P. R. China
| | - Suying Xu
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
- Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control, Department of Environmental Science and Engineering, North China Electric Power University Baoding 071003 P. R. China
| | - Tony D James
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
| | - Sofia I Pascu
- Department of Chemistry, University of Bath Calverton Down Bath BA2 7AY UK
- Centre for Therapeutic Innovation, University of Bath BA2 7AY UK
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4
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Quantifying postsynaptic receptor dynamics: insights into synaptic function. Nat Rev Neurosci 2023; 24:4-22. [PMID: 36352031 DOI: 10.1038/s41583-022-00647-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
The molecular composition of presynaptic and postsynaptic neuronal terminals is dynamic, and yet long-term stabilizations in postsynaptic responses are necessary for synaptic development and long-term plasticity. The need to reconcile these concepts is further complicated by learning- and memory-related plastic changes in the molecular make-up of synapses. Advances in single-particle tracking mean that we can now quantify the number and diffusive properties of specific synaptic molecules, while statistical thermodynamics provides a framework to analyse these molecular fluctuations. In this Review, we discuss the use of these approaches to gain quantitative descriptions of the processes underlying the turnover, long-term stability and plasticity of postsynaptic receptors and show how these can help us to understand the balance between local molecular turnover and synaptic structural identity and integrity.
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5
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Öcal N, Ceylan A, Duman F. Eco-Friendly Intracellular Biosynthesis of CdS Quantum Dots Using Pseudomonas aeruginosa: Evaluation of Antimicrobial Effects and DNA Cleavage Activities. RECENT PATENTS ON NANOTECHNOLOGY 2023; 17:59-67. [PMID: 34825647 DOI: 10.2174/1872210515666210719122353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/23/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Intracellular biosynthesis of Quantum Dots (QDs) based on microorganisms offers a green alternative and eco-friendly for the production of nanocrystals with superior properties. This study focused on the production of intracellular CdS QDs by stimulating the detoxification metabolism of Pseudomonas aeruginosa. METHODS For this aim, Pseudomonas aeruginosa ATCC 27853 strain was incubated in a solution of 1mM cadmium sulphate (CdSO4) to manipulate the detoxification mechanism. The intracellularly formed Cd-based material was extracted, and its characterization was carried out by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Energy Dispersive X-ray (EDX) and dynamic light scattering (DLS) analyses and absorption-emission spectra. RESULTS The obtained material showed absorption peaks at 385 nm and a luminescence peak at 411 nm, and the particle sizes were measured in the range 4.63-17.54 nm. It was determined that the material was sphere-shaped, with a cubic crystalline structure, including Cd and S elements. The antibacterial and antifungal activities of CdS QDs against patent eleven bacterial (four Grampositive and seven Gram-negative) and one fungal strains were investigated by the agar disk diffusion method. It was revealed that the obtained material has antibacterial effects on both Grampositive and Gram-negative bacteria. However, cleavage activity of CdS QDs on pBR322 DNA was not detected. CONCLUSION As a result, it has been proposed that the stimulation of the detoxification mechanism can be an easy and effective way of producing green and cheap luminescent QDs or nanomaterial.
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Affiliation(s)
- Necip Öcal
- Department of Biology, Faculty of Science, Erciyes University, 38280, Kayseri, Turkey
| | - Ahmet Ceylan
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Erciyes University, 38280, Kayseri, Turkey
| | - Fatih Duman
- Department of Biology, Faculty of Science, Erciyes University, 38280, Kayseri, Turkey
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6
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Xu X, Ge X, Xiong H, Qin Z. Toward dynamic, anisotropic, high-resolution, and functional measurement in the brain extracellular space. NEUROPHOTONICS 2022; 9:032210. [PMID: 35573823 PMCID: PMC9094757 DOI: 10.1117/1.nph.9.3.032210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 03/31/2022] [Indexed: 06/15/2023]
Abstract
Diffusion of substances in the brain extracellular space (ECS) is important for extrasynaptic communication, extracellular ionic homeostasis, drug delivery, and metabolic waste clearance. However, substance diffusion is largely constrained by the geometry of brain ECS and the extracellular matrix. Investigating the diffusion properties of substances not only reveals the structural information of the brain ECS but also advances the understanding of intercellular signaling of brain cells. Among different techniques for substance diffusion measurement, the optical imaging method is sensitive and straightforward for measuring the dynamics and distribution of fluorescent molecules or sensors and has been used for molecular diffusion measurement in the brain. We mainly discuss recent advances of optical imaging-enabled measurements toward dynamic, anisotropic, high-resolution, and functional aspects of the brain ECS diffusion within the last 5 to 10 years. These developments are made possible by advanced imaging, such as light-sheet microscopy and single-particle tracking in tissue, and new fluorescent biosensors for neurotransmitters. We envision future efforts to map the ECS diffusivity across the brain under healthy and diseased conditions to guide the therapeutic delivery and better understand neurochemical transmissions that are relevant to physiological signaling and functions in brain circuits.
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Affiliation(s)
- Xueqi Xu
- University of Texas at Dallas, Department of Mechanical Engineering, Richardson, Texas, United States
| | - Xiaoqian Ge
- University of Texas at Dallas, Department of Mechanical Engineering, Richardson, Texas, United States
| | - Hejian Xiong
- University of Texas at Dallas, Department of Mechanical Engineering, Richardson, Texas, United States
| | - Zhenpeng Qin
- University of Texas at Dallas, Department of Mechanical Engineering, Richardson, Texas, United States
- University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, United States
- University of Texas at Southwestern Medical Center, Department of Surgery, Richardson, Texas, United States
- University of Texas at Dallas, The Center for Advanced Pain Studies, Richardson, Texas, United States
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7
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Tsortouktzidis D, Tröscher AR, Schulz H, Opitz T, Schoch S, Becker AJ, van Loo KMJ. A Versatile Clustered Regularly Interspaced Palindromic Repeats Toolbox to Study Neurological CaV3.2 Channelopathies by Promoter-Mediated Transcription Control. Front Mol Neurosci 2022; 14:667143. [PMID: 35069110 PMCID: PMC8770422 DOI: 10.3389/fnmol.2021.667143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 12/15/2021] [Indexed: 11/15/2022] Open
Abstract
Precise genome editing in combination with viral delivery systems provides a valuable tool for neuroscience research. Traditionally, the role of genes in neuronal circuits has been addressed by overexpression or knock-out/knock-down systems. However, those techniques do not manipulate the endogenous loci and therefore have limitations. Those constraints include that many genes exhibit extensive alternative splicing, which can be regulated by neuronal activity. This complexity cannot be easily reproduced by overexpression of one protein variant. The CRISPR activation and interference/inhibition systems (CRISPRa/i) directed to promoter sequences can modulate the expression of selected target genes in a highly specific manner. This strategy could be particularly useful for the overexpression of large proteins and for alternatively spliced genes, e.g., for studying large ion channels known to be affected in ion channelopathies in a variety of neurological diseases. Here, we demonstrate the feasibility of a newly developed CRISPRa/i toolbox to manipulate the promoter activity of the Cacna1h gene. Impaired, function of the low-voltage-activated T-Type calcium channel CaV3.2 is involved in genetic/mutational as well as acquired/transcriptional channelopathies that emerge with epileptic seizures. We show CRISPR-induced activation and inhibition of the Cacna1h locus in NS20Y cells and primary cortical neurons, as well as activation in mouse organotypic slice cultures. In future applications, the system offers the intriguing perspective to study functional effects of gain-of-function or loss-of-function variations in the Cacna1h gene in more detail. A better understanding of CaV3.2 channelopathies might result in a major advancement in the pharmacotherapy of CaV3.2 channelopathy diseases.
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Affiliation(s)
- Despina Tsortouktzidis
- Institute of Neuropathology, Medical Faculty, Section for Translational Epilepsy Research, University of Bonn, Bonn, Germany
| | - Anna R. Tröscher
- Institute of Neuropathology, Medical Faculty, Section for Translational Epilepsy Research, University of Bonn, Bonn, Germany
- Department of Neurology, Kepler University Hospital, Johannes Kepler University Linz, Linz, Austria
| | - Herbert Schulz
- Department of Microgravity and Translational Regenerative Medicine, Clinic for Plastic, Aesthetic and Hand Surgery, Otto von Guericke University, Magdeburg, Germany
| | - Thoralf Opitz
- Institute of Experimental Epileptology and Cognition Research, Medical Faculty, University of Bonn, Bonn, Germany
| | - Susanne Schoch
- Institute of Neuropathology, Medical Faculty, Section for Translational Epilepsy Research, University of Bonn, Bonn, Germany
| | - Albert J. Becker
- Institute of Neuropathology, Medical Faculty, Section for Translational Epilepsy Research, University of Bonn, Bonn, Germany
| | - Karen M. J. van Loo
- Institute of Neuropathology, Medical Faculty, Section for Translational Epilepsy Research, University of Bonn, Bonn, Germany
- Department of Epileptology and Neurology, RWTH Aachen University, Aachen, Germany
- *Correspondence: Karen M. J. van Loo,
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8
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Klatt O, Repetto D, Brockhaus J, Reissner C, El Khallouqi A, Rohlmann A, Heine M, Missler M. Endogenous β-neurexins on axons and within synapses show regulated dynamic behavior. Cell Rep 2021; 35:109266. [PMID: 34133920 DOI: 10.1016/j.celrep.2021.109266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 12/21/2020] [Accepted: 05/26/2021] [Indexed: 11/25/2022] Open
Abstract
Neurexins are key organizer molecules that regulate synaptic function and are implicated in autism and schizophrenia. β-neurexins interact with numerous cell adhesion and receptor molecules, but their neuronal localization remains elusive. Using single-molecule tracking and high-resolution microscopy to detect neurexin1β and neurexin3β in primary hippocampal neurons from knockin mice, we demonstrate that endogenous β-neurexins are present in fewer than half of excitatory and inhibitory synapses. Moreover, we observe a large extrasynaptic pool of β-neurexins on axons and show that axonal β-neurexins diffuse with higher surface mobility than those transiently confined within synapses. Stimulation of neuronal activity further increases the mobility of synaptic and axonal β-neurexins, whereas inhibition causes the opposite. Blocking ectodomain cleavage by metalloproteases also reduces β-neurexin mobility and enhances glutamate release. These findings suggest that the surface mobility of endogenous β-neurexins inside and outside of synapses is dynamically regulated and linked to neuronal activity.
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Affiliation(s)
- Oliver Klatt
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany; Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Carsten Reissner
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Abderazzaq El Khallouqi
- Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany
| | - Astrid Rohlmann
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Martin Heine
- Functional Neurobiology Group, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University, 55128 Mainz, Germany.
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany.
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9
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Intracellular biosynthesis of PbS quantum dots using Pseudomonas aeruginosa ATCC 27853: evaluation of antibacterial effects and DNA cleavage activities. World J Microbiol Biotechnol 2020; 36:147. [DOI: 10.1007/s11274-020-02917-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/13/2020] [Indexed: 10/23/2022]
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10
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Bannai H, Niwa F, Sakuragi S, Mikoshiba K. Inhibitory synaptic transmission tuned by Ca 2+ and glutamate through the control of GABA A R lateral diffusion dynamics. Dev Growth Differ 2020; 62:398-406. [PMID: 32329058 PMCID: PMC7496684 DOI: 10.1111/dgd.12667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/08/2020] [Accepted: 04/18/2020] [Indexed: 11/30/2022]
Abstract
The GABAergic synapses, a primary inhibitory synapse in the mammalian brain, is important for the normal development of brain circuits, and for the regulation of the excitation‐inhibition balance critical for brain function from the developmental stage throughout life. However, the molecular mechanism underlying the formation, maintenance, and modulation of GABAergic synapses is less understood compared to that of excitatory synapses. Quantum dot‐single particle tracking (QD‐SPT), a super‐resolution imaging technique that enables the analysis of membrane molecule dynamics at single‐molecule resolution, is a powerful tool to analyze the behavior of proteins and lipids on the plasma membrane. In this review, we summarize the recent application of QD‐SPT in understanding of GABAergic synaptic transmission. Here we introduce QD‐SPT experiments that provide further insights into the molecular mechanism supporting GABAergic synapses. QD‐SPT studies revealed that glutamate and Ca2+ signaling is involved in (a) the maintenance of GABAergic synapses, (b) GABAergic long‐term depression, and GABAergic long‐term potentiation, by specifically activating signaling pathways unique to each phenomenon. We also introduce a novel Ca2+ imaging technique to describe the diversity of Ca2+ signals that may activate the downstream signaling pathways that induce specific biological output.
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Affiliation(s)
- Hiroko Bannai
- School of Advanced Science and Engineering, Department of Electrical Engineering and Biosciences, Waseda University, Tokyo, Japan.,Department of Neurophysiology, Keio University School of Medicine, Tokyo, Japan.,Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama, Japan.,Laboratory for Developmental Neurobiology, RIKEN Center for Brain Science, Wako, Japan
| | - Fumihiro Niwa
- Laboratory for Developmental Neurobiology, RIKEN Center for Brain Science, Wako, Japan.,Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, PSL Research University, INSERM, CNRS, Paris, France
| | - Shigeo Sakuragi
- School of Advanced Science and Engineering, Department of Electrical Engineering and Biosciences, Waseda University, Tokyo, Japan.,Department of Pharmacology, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Center for Brain Science, Wako, Japan.,Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, China.,Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Japan
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11
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Fagan RR, Kearney PJ, Melikian HE. In Situ Regulated Dopamine Transporter Trafficking: There's No Place Like Home. Neurochem Res 2020; 45:1335-1343. [PMID: 32146647 DOI: 10.1007/s11064-020-03001-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/13/2022]
Abstract
Dopamine (DA) is critical for motivation, reward, movement initiation, and learning. Mechanisms that control DA signaling have a profound impact on these important behaviors, and additionally play a role in DA-related neuropathologies. The presynaptic SLC6 DA transporter (DAT) limits extracellular DA levels by clearing released DA, and is potently inhibited by addictive and therapeutic psychostimulants. Decades of evidence support that the DAT is subject to acute regulation by a number of signaling pathways, and that endocytic trafficking strongly regulates DAT availability and function. DAT trafficking studies have been performed in a variety of model systems, including both in vitro and ex vivo preparations. In this review, we focus on the breadth of DAT trafficking studies, with specific attention to, and comparison of, how context may influence DAT's response to different stimuli. In particular, this overview highlights that stimulated DAT trafficking not only differs between in vitro and ex vivo environments, but also is influenced by both sex and anatomical subregions.
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Affiliation(s)
- Rita R Fagan
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Patrick J Kearney
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Haley E Melikian
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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12
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Thal LB, Mann VR, Sprinzen D, McBride JR, Reid KR, Tomlinson ID, McMahon DG, Cohen BE, Rosenthal SJ. Ligand-conjugated quantum dots for fast sub-diffraction protein tracking in acute brain slices. Biomater Sci 2020; 8:837-845. [PMID: 31790090 PMCID: PMC7002256 DOI: 10.1039/c9bm01629e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Semiconductor quantum dots (QDs) have demonstrated utility in long-term single particle tracking of membrane proteins in live cells in culture. To extend the superior optical properties of QDs to more physiologically relevant cell platforms, such as acute brain slices, we examine the photophysics of compact ligand-conjugated CdSe/CdS QDs using both ensemble and single particle analysis in brain tissue media. We find that symmetric core passivation is critical for both photostability in oxygenated media and for prolonged single particle imaging in brain slices. We then demonstrate the utility of these QDs by imaging single dopamine transporters in acute brain slices, achieving 20 nm localization precision at 10 Hz frame rates. These findings detail design requirements needed for new QD probes in complex living environments, and open the door to physiologically relevant studies that capture the utility of QD probes in acute brain slices.
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Affiliation(s)
- Lucas B Thal
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
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13
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Dupuis JP, Groc L. Surface trafficking of neurotransmitter receptors: From cultured neurons to intact brain preparations. Neuropharmacology 2019; 169:107642. [PMID: 31108111 DOI: 10.1016/j.neuropharm.2019.05.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 12/14/2022]
Abstract
Over the last decade, developments in single molecule imaging have changed our vision of synaptic physiology. By providing high spatio-temporal resolution maps of the molecular actors of neurotransmissions, these techniques have revealed that pre- and post-synaptic proteins are not randomly distributed but precisely organized at the nanoscale, and that this specific organization is dynamically regulated. At the centre of synaptic transmissions, neurotransmitter receptors have been shown to form nanodomains at synapses and to dynamically move in and out of these confinement areas through lateral diffusion within the membrane plane on millisecond timescales, thereby directly contributing to the regulation of synaptic transmission and plasticity. Since the vast majority of these discoveries originated from observations made on dissociated neurons lacking several features of brain tissue (e.g. three-dimensional organization, tissue density), they were initially considered with caution. However, the recent implementation of single-particle tracking (SPT) approaches in cultured and acute brain preparations confirmed that early findings on the dynamic properties of receptors at the surface of neurons can be extended to more physiological conditions. Taking example of dopamine D1 and NMDA glutamate receptors we here review our current knowledge of the features of neurotransmitter receptor surface diffusion in intact brain tissue. Through detailed comparison with cultured neurons, we also discuss how these biophysical properties are influenced by the complexity of the extracellular environment. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Julien P Dupuis
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000, Bordeaux, France; CNRS, IINS UMR 5297, 33000, Bordeaux, France
| | - Laurent Groc
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000, Bordeaux, France; CNRS, IINS UMR 5297, 33000, Bordeaux, France.
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14
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Zhou W, Du Y, Zeng J, Liu F, Zhu Y. A modified "gel-blowing" strategy toward the one-step mass production of a 3D N-doped carbon nanosheet@carbon nanotube hybrid network for supercapacitors. NANOSCALE 2019; 11:7624-7633. [PMID: 30758004 DOI: 10.1039/c8nr10348h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this work, we have realized the synchronous and large-scale synthesis of one-dimensional (1D) carbon nanotubes (CNTs) on two-dimensional (2D) N-doped carbon nanosheets (NCNS) by a one-step annealing of a Ni-containing gel precursor. Upon heating, the gel is "blown" into large-sized 2D NCNS with uniformly embedded Ni nanoparticles that can catalyze the in situ CNT growth, forming a three-dimensional (3D) N-doped carbon nanosheet@carbon nanotube (NCNS@CNT) hybrid. Different from our previous "gel-blowing" strategy for 2D nanosheets, the modified "gel-blowing" strategy is capable of producing 3D architecture by employing a new complexing agent and introducing ethanol as a carbon source. Importantly, this method can be easily scaled up by annealing more gel precursors with an increased amount of ethanol. The introduction of CNTs endows NCNS@CNTs with higher quality and larger specific surface area (SSA) than pure NCNS. Consequently, the electrochemical performance of 3D NCNS@CNTs is much superior to that of 2D NCNS and found to be related with the annealing temperature. The optimized NCNS@CNTs can deliver a specific capacitance of 124 F g-1 at 1 A g-1 and maintain 88% of their initial value after 10 000 cycles at 1 A g-1. Furthermore, NiO nanosheets are deposited on the NCNS@CNT framework to study its function as a conductive host. The as-fabricated hybrid electrode exhibits a high specific capacitance of 660 F g-1 at 1 A g-1 and 532 F g-1 at 20 A g-1, which is also better than its counterpart using NCNS as substrates. This method provides a simplified and low-cost way towards the mass production of NCNS@CNTs for energy application and beyond.
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Affiliation(s)
- Weiwei Zhou
- School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China.
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15
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Chamma I, Sainlos M, Thoumine O. Biophysical mechanisms underlying the membrane trafficking of synaptic adhesion molecules. Neuropharmacology 2019; 169:107555. [PMID: 30831159 DOI: 10.1016/j.neuropharm.2019.02.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/14/2019] [Accepted: 02/27/2019] [Indexed: 01/13/2023]
Abstract
Adhesion proteins play crucial roles at synapses, not only by providing a physical trans-synaptic linkage between axonal and dendritic membranes, but also by connecting to functional elements including the pre-synaptic neurotransmitter release machinery and post-synaptic receptors. To mediate these functions, adhesion proteins must be organized on the neuronal surface in a precise and controlled manner. Recent studies have started to describe the mobility, nanoscale organization, and turnover rate of key synaptic adhesion molecules including cadherins, neurexins, neuroligins, SynCAMs, and LRRTMs, and show that some of these proteins are highly mobile in the plasma membrane while others are confined at sub-synaptic compartments, providing evidence for different regulatory pathways. In this review article, we provide a biophysical view of the diffusional trapping of adhesion molecules at synapses, involving both extracellular and intracellular protein interactions. We review the methodology underlying these measurements, including biomimetic systems with purified adhesion proteins, means to perturb protein expression or function, single molecule imaging in cultured neurons, and analytical models to interpret the data. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Ingrid Chamma
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France
| | - Matthieu Sainlos
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France
| | - Olivier Thoumine
- Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000, Bordeaux, France.
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16
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Dynamics, nanoscale organization, and function of synaptic adhesion molecules. Mol Cell Neurosci 2018; 91:95-107. [DOI: 10.1016/j.mcn.2018.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 04/12/2018] [Accepted: 04/13/2018] [Indexed: 12/13/2022] Open
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17
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Kovtun O, Tomlinson ID, Bailey DM, Thal LB, Ross EJ, Harris L, Frankland MP, Ferguson RS, Glaser Z, Greer J, Rosenthal SJ. Single Quantum Dot Tracking Illuminates Neuroscience at the Nanoscale. Chem Phys Lett 2018; 706:741-752. [PMID: 30270931 PMCID: PMC6157616 DOI: 10.1016/j.cplett.2018.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The use of nanometer-sized semiconductor crystals, known as quantum dots, allows us to directly observe individual biomolecular transactions through a fluorescence microscope. Here, we review the evolution of single quantum dot tracking over the past two decades, highlight key biophysical discoveries facilitated by quantum dots, briefly discuss biochemical and optical implementation strategies for a single quantum dot tracking experiment, and report recent accomplishments of our group at the interface of molecular neuroscience and nanoscience.
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Affiliation(s)
- Oleg Kovtun
- Departments of Chemistry, Chemical Biology, Vanderbilt University
- Departments of Vanderbilt Institute of Nanoscale Science and Engineering
| | - Ian D. Tomlinson
- Departments of Chemistry, Chemical Biology, Vanderbilt University
- Departments of Vanderbilt Institute of Nanoscale Science and Engineering
| | - Danielle M. Bailey
- Departments of Chemistry, Chemical Biology, Vanderbilt University
- Departments of Pharmacology, Chemical Biology, Vanderbilt University
- Departments of Vanderbilt Institute of Nanoscale Science and Engineering
| | - Lucas B. Thal
- Departments of Chemistry, Chemical Biology, Vanderbilt University
- Departments of Vanderbilt Institute of Nanoscale Science and Engineering
- Departments of Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN
| | - Emily J. Ross
- Departments of Hudson Alpha Institute for Biotechnology, Huntsville, AL
| | - Lauren Harris
- Departments of Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN
| | | | | | - Zachary Glaser
- Departments of Chemistry, Chemical Biology, Vanderbilt University
| | - Jonathan Greer
- Departments of Chemistry, Chemical Biology, Vanderbilt University
| | - Sandra J. Rosenthal
- Departments of Chemistry, Chemical Biology, Vanderbilt University
- Departments of Pharmacology, Chemical Biology, Vanderbilt University
- Departments of Chemical and Biomolecular Engineering, Chemical Biology, Vanderbilt University
- Departments of Physics and Astronomy, Chemical Biology, Vanderbilt University
- Departments of Vanderbilt Institute of Nanoscale Science and Engineering
- Departments of Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN
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18
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α-Neurexins Together with α2δ-1 Auxiliary Subunits Regulate Ca 2+ Influx through Ca v2.1 Channels. J Neurosci 2018; 38:8277-8294. [PMID: 30104341 DOI: 10.1523/jneurosci.0511-18.2018] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/03/2018] [Accepted: 07/10/2018] [Indexed: 11/21/2022] Open
Abstract
Action potential-evoked neurotransmitter release is impaired in knock-out neurons lacking synaptic cell-adhesion molecules α-neurexins (αNrxns), the extracellularly longer variants of the three vertebrate Nrxn genes. Ca2+ influx through presynaptic high-voltage gated calcium channels like the ubiquitous P/Q-type (CaV2.1) triggers release of fusion-ready vesicles at many boutons. α2δ Auxiliary subunits regulate trafficking and kinetic properties of CaV2.1 pore-forming subunits but it has remained unclear if this involves αNrxns. Using live cell imaging with Ca2+ indicators, we report here that the total presynaptic Ca2+ influx in primary hippocampal neurons of αNrxn triple knock-out mice of both sexes is reduced and involved lower CaV2.1-mediated transients. This defect is accompanied by lower vesicle release, reduced synaptic abundance of CaV2.1 pore-forming subunits, and elevated surface mobility of α2δ-1 on axons. Overexpression of Nrxn1α in αNrxn triple knock-out neurons is sufficient to restore normal presynaptic Ca2+ influx and synaptic vesicle release. Moreover, coexpression of Nrxn1α together with α2δ-1 subunits facilitates Ca2+ influx further but causes little augmentation together with a different subunit, α2δ-3, suggesting remarkable specificity. Expression of defined recombinant CaV2.1 channels in heterologous cells validates and extends the findings from neurons. Whole-cell patch-clamp recordings show that Nrxn1α in combination with α2δ-1, but not with α2δ-3, facilitates Ca2+ currents of recombinant CaV2.1 without altering channel kinetics. These results suggest that presynaptic Nrxn1α acts as a positive regulator of Ca2+ influx through CaV2.1 channels containing α2δ-1 subunits. We propose that this regulation represents an important way for neurons to adjust synaptic strength.SIGNIFICANCE STATEMENT Synaptic transmission between neurons depends on the fusion of neurotransmitter-filled vesicles with the presynaptic membrane, which subsequently activates postsynaptic receptors. Influx of calcium ions into the presynaptic terminal is the key step to trigger vesicle release and involves different subtypes of voltage-gated calcium channels. We study the regulation of calcium channels by neurexins, a family of synaptic cell-adhesion molecules that are essential for many synapse properties. Using optical measurements of calcium influx in cultured neurons and electrophysiological recordings of calcium currents from recombinant channels, we show that a major neurexin variant facilitates calcium influx through P/Q-type channels by interacting with their α2δ-1 auxiliary subunits. These results propose a novel way how neurons can modulate the strength of distinct synapses.
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19
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Barabás K, Godó S, Lengyel F, Ernszt D, Pál J, Ábrahám IM. Rapid non-classical effects of steroids on the membrane receptor dynamics and downstream signaling in neurons. Horm Behav 2018; 104:183-191. [PMID: 29775570 DOI: 10.1016/j.yhbeh.2018.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/26/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Although rapid effects of steroid hormones on membrane receptors and intracellular signaling molecules have been extensively studied in neurons, we are only beginning to understand the molecular mechanisms behind these non-classical steroid actions. Single molecule tracking (SMT) studies on live cells demonstrated that surface trafficking of membrane receptors determines their ligand binding properties and downstream signaling events. Recent findings suggest that one of the underlying mechanisms of non-classical steroid actions is the alteration of receptor movements on the membrane surface. In order to highlight this novel aspect of steroid effects, we first address the types of receptor movements in the plasma membrane and the role of cortical actin dynamics in receptor movement. We then discuss how single molecules and the surface movements of receptors can be detected in live cells. Next, we review the fundamental processes, which determine the effect of steroids on the plasma membrane: steroid movement through the lipid bilayer and the role of steroid membrane receptors. Using glutamate and neurotrophin receptors (NTRs) as examples, we demonstrate the features of receptor dynamics in the membrane. In addition, we survey the available data of rapid steroid actions on membrane receptor trafficking: we discuss how glucocorticoids act on the surface diffusion of glutamate receptor molecules and how estradiol acts on NTRs and gamma-aminobutyric acid type A receptors (GABAARs) and their related signaling events as well as on cortical actin. Finally, we address the physiological relevance of rapid steroid action on membrane receptors dynamics.
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Affiliation(s)
- Klaudia Barabás
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Soma Godó
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Ferenc Lengyel
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Dávid Ernszt
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - József Pál
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - István M Ábrahám
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary.
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20
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Karch S, Broichhagen J, Schneider J, Böning D, Hartmann S, Schmid B, Tripal P, Palmisano R, Alzheimer C, Johnsson K, Huth T. A New Fluorogenic Small-Molecule Labeling Tool for Surface Diffusion Analysis and Advanced Fluorescence Imaging of β-Site Amyloid Precursor Protein-Cleaving Enzyme 1 Based on Silicone Rhodamine: SiR-BACE1. J Med Chem 2018; 61:6121-6139. [PMID: 29939737 DOI: 10.1021/acs.jmedchem.8b00387] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
β-site APP-cleaving enzyme 1 (BACE1) is a major player in the pathogenesis of Alzheimer's disease. Structural and functional fluorescence microscopy offers a powerful approach to learn about the physiology and pathophysiology of this protease. Up to now, however, common labeling techniques require genetic manipulation, use large antibodies, or are not compatible with live cell imaging. Fluorescent small molecules that specifically bind to the protein of interest can overcome these limitations. Herein, we introduce SiR-BACE1, a conjugate of the BACE1 inhibitor S-39 and SiR647, as a novel fluorogenic, tag-free, and antibody-free label for BACE1. We present its chemical development, characterize its photophysical and pharmacologic properties, and evaluate its behavior in solution, in overexpression systems, and in native brain tissue. We demonstrate its applicability in confocal, stimulated emission depletion and dynamic single-molecule microscopy. The first functional studies with SiR-BACE1 on the surface mobility of BACE1 revealed a markedly confined diffusion pattern.
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Affiliation(s)
- Sandra Karch
- Institute of Physiology and Pathophysiology , Friedrich-Alexander-Universität Erlangen-Nürnberg , Universitaetsstrasse 17 , 91054 Erlangen , Germany
| | - Johannes Broichhagen
- Department of Chemical Biology , Max Planck Institute for Medical Research , Jahnstrasse 29 , 69120 Heidelberg , Germany.,Laboratory of Protein Engineering, Institut des Sciences et Ingénierie Chimiques, Sciences de Base , École Polytechnique Fédérale Lausanne , 1015 Lausanne , Switzerland
| | - Julia Schneider
- Institute of Physiology and Pathophysiology , Friedrich-Alexander-Universität Erlangen-Nürnberg , Universitaetsstrasse 17 , 91054 Erlangen , Germany
| | - Daniel Böning
- Max Planck Institute for the Science of Light , Staudtstrasse 2 , 91058 Erlangen , Germany
| | - Stephanie Hartmann
- Institute of Physiology and Pathophysiology , Friedrich-Alexander-Universität Erlangen-Nürnberg , Universitaetsstrasse 17 , 91054 Erlangen , Germany
| | - Benjamin Schmid
- Optical Imaging Centre , Friedrich-Alexander-Universität Erlangen-Nürnberg , Hartmannstrasse 14 , 91052 Erlangen , Germany
| | - Philipp Tripal
- Optical Imaging Centre , Friedrich-Alexander-Universität Erlangen-Nürnberg , Hartmannstrasse 14 , 91052 Erlangen , Germany
| | - Ralf Palmisano
- Optical Imaging Centre , Friedrich-Alexander-Universität Erlangen-Nürnberg , Hartmannstrasse 14 , 91052 Erlangen , Germany
| | - Christian Alzheimer
- Institute of Physiology and Pathophysiology , Friedrich-Alexander-Universität Erlangen-Nürnberg , Universitaetsstrasse 17 , 91054 Erlangen , Germany
| | - Kai Johnsson
- Department of Chemical Biology , Max Planck Institute for Medical Research , Jahnstrasse 29 , 69120 Heidelberg , Germany.,Laboratory of Protein Engineering, Institut des Sciences et Ingénierie Chimiques, Sciences de Base , École Polytechnique Fédérale Lausanne , 1015 Lausanne , Switzerland
| | - Tobias Huth
- Institute of Physiology and Pathophysiology , Friedrich-Alexander-Universität Erlangen-Nürnberg , Universitaetsstrasse 17 , 91054 Erlangen , Germany
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21
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Tracking single membrane targets of human autoantibodies using single nanoparticle imaging. J Neurosci Methods 2018; 304:76-82. [PMID: 29684464 DOI: 10.1016/j.jneumeth.2018.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/06/2018] [Accepted: 04/17/2018] [Indexed: 11/23/2022]
Abstract
BACKGROUND Over the past decade, an increasing number of neurological and neuropsychiatric diseases have been associated with the expression of autoantibodies directed against neuronal targets, including neurotransmitter receptors. Although cell-based assays are routinely used in clinics to detect the presence of immunoglobulins, such tests often provide heterogeneous outcomes due to their limited sensitivity, especially at low titers. Thus, there is an urging need for new methods allowing the detection of autoantibodies in seropositive patients that cannot always be clinically distinguished from seronegative ones. NEW METHOD Here we make a case for single nanoparticle imaging approaches as a highly sensitive antibody detection assay. Through high-affinity interactions between functionalized nanoparticles and autoantibodies that recognize extracellular domains of membrane neuronal targets, single nanoparticle imaging allows a live surface staining of transmembrane proteins and gives access to their surface dynamics. RESULTS AND COMPARISON WITH EXISTING METHOD(S) We show here that this method is well-suited to detect low titers of purified immunoglobulin G (IgG) from first-episode psychotic patients and demonstrate that these IgG target glutamatergic N-Methyl-d-Aspartate receptors (NMDAR) in live hippocampal neurons. The molecular behaviors of targeted membrane receptors were indistinguishable from those of endogenous GluN1 NMDAR subunit and were virtually independent of the IgG concentration present in the sample contrary to classical cell-based assays. CONCLUSIONS Single nanoparticle imaging emerges as a real-time sensitive method to detect IgG directed against neuronal surface proteins, which could be used as an additional step to rule out ambiguous seropositivity diagnoses.
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22
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Modi S, Higgs NF, Sheehan D, Griffin LD, Kittler JT. Quantum dot conjugated nanobodies for multiplex imaging of protein dynamics at synapses. NANOSCALE 2018; 10:10241-10249. [PMID: 29790493 PMCID: PMC5977936 DOI: 10.1039/c7nr09130c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/12/2018] [Indexed: 06/08/2023]
Abstract
Neurons communicate with each other through synapses, which show enrichment for specialized receptors. Although many studies have explored spatial enrichment and diffusion of these receptors in dissociated neurons using single particle tracking, much less is known about their dynamic properties at synapses in complex tissue like brain slices. Here we report the use of smaller and highly specific quantum dots conjugated with a recombinant single domain antibody fragment (VHH fragment) against green fluorescent protein to provide information on diffusion of adhesion molecules at the growth cone and neurotransmitter receptors at synapses. Our data reveals that QD-nanobodies can measure neurotransmitter receptor dynamics at both excitatory and inhibitory synapses in primary neuronal cultures as well as in ex vivo rat brain slices. We also demonstrate that this approach can be applied to tagging multiple proteins to simultaneously monitor their behavior. Thus, we provide a strategy for multiplex imaging of tagged membrane proteins to study their clustering, diffusion and transport both in vitro as well as in native tissue environments such as brain slices.
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Affiliation(s)
- Souvik Modi
- Neuroscience
, Physiology and Pharmacology
, University College London. Gower Street
,
London
, WC1E 6BT
, UK
.
- Tata Institute of Fundamental Research
,
Homi Bhabha Road
, Mumbai
, 400005
, India
| | - Nathalie F. Higgs
- Neuroscience
, Physiology and Pharmacology
, University College London. Gower Street
,
London
, WC1E 6BT
, UK
.
| | - David Sheehan
- Neuroscience
, Physiology and Pharmacology
, University College London. Gower Street
,
London
, WC1E 6BT
, UK
.
| | | | - Josef T. Kittler
- Neuroscience
, Physiology and Pharmacology
, University College London. Gower Street
,
London
, WC1E 6BT
, UK
.
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23
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Single quantum dot tracking reveals the impact of nanoparticle surface on intracellular state. Nat Commun 2018; 9:1830. [PMID: 29739927 PMCID: PMC5940692 DOI: 10.1038/s41467-018-04185-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 04/09/2018] [Indexed: 12/21/2022] Open
Abstract
Inefficient delivery of macromolecules and nanoparticles to intracellular targets is a major bottleneck in drug delivery, genetic engineering, and molecular imaging. Here we apply live-cell single-quantum-dot imaging and tracking to analyze and classify nanoparticle states after intracellular delivery. By merging trajectory diffusion parameters with brightness measurements, multidimensional analysis reveals distinct and heterogeneous populations that are indistinguishable using single parameters alone. We derive new quantitative metrics of particle loading, cluster distribution, and vesicular release in single cells, and evaluate intracellular nanoparticles with diverse surfaces following osmotic delivery. Surface properties have a major impact on cell uptake, but little impact on the absolute cytoplasmic numbers. A key outcome is that stable zwitterionic surfaces yield uniform cytosolic behavior, ideal for imaging agents. We anticipate that this combination of quantum dots and single-particle tracking can be widely applied to design and optimize next-generation imaging probes, nanoparticle therapeutics, and biologics.
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24
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Advances in surface-coated single-walled carbon nanotubes as near-infrared photoluminescence emitters for single-particle tracking applications in biological environments. Polym J 2018. [DOI: 10.1038/s41428-018-0052-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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25
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Ribeiro LF, Verpoort B, de Wit J. Trafficking mechanisms of synaptogenic cell adhesion molecules. Mol Cell Neurosci 2018; 91:34-47. [PMID: 29631018 DOI: 10.1016/j.mcn.2018.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/01/2023] Open
Abstract
Nearly every aspect of neuronal function, from wiring to information processing, critically depends on the highly polarized architecture of neurons. Establishing and maintaining the distinct molecular composition of axonal and dendritic compartments requires precise control over the trafficking of the proteins that make up these cellular domains. Synaptic cell adhesion molecules (CAMs), membrane proteins with a critical role in the formation, differentiation and plasticity of synapses, require targeting to the correct pre- or postsynaptic compartment for proper functioning of neural circuits. However, the mechanisms that control the polarized trafficking, synaptic targeting, and synaptic abundance of CAMs are poorly understood. Here, we summarize current knowledge about the sequential trafficking events along the secretory pathway that control the polarized surface distribution of synaptic CAMs, and discuss how their synaptic targeting and abundance is additionally influenced by post-secretory determinants. The identification of trafficking-impairing mutations in CAMs associated with various neurodevelopmental disorders underscores the importance of correct protein trafficking for normal brain function.
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Affiliation(s)
- Luís F Ribeiro
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Ben Verpoort
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; KU Leuven, Department of Neurosciences, Herestraat 49, 3000 Leuven, Belgium.
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26
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Bailey DM, Kovtun O, Rosenthal SJ. Antibody-Conjugated Single Quantum Dot Tracking of Membrane Neurotransmitter Transporters in Primary Neuronal Cultures. Methods Mol Biol 2018; 1570:165-177. [PMID: 28238136 DOI: 10.1007/978-1-4939-6840-4_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Single particle tracking (SPT) experiments have provided the scientific community with invaluable single-molecule information about the dynamic regulation of individual receptors, transporters, kinases, lipids, and molecular motors. SPT is an alternative to ensemble averaging approaches, where heterogeneous modes of motion might be lost. Quantum dots (QDs) are excellent probes for SPT experiments due to their photostability, high brightness, and size-dependent, narrow emission spectra. In a typical QD-based SPT experiment, QDs are bound to the target of interest and imaged for seconds to minutes via fluorescence video microscopy. Single QD spots in individual frames are then linked to form trajectories that are analyzed to determine their mean square displacement, diffusion coefficient, confinement index, and instantaneous velocity. This chapter describes a generalizable protocol for the single particle tracking of membrane neurotransmitter transporters on cell membranes with either unmodified extracellular antibody probes and secondary antibody-conjugated quantum dots or biotinylated extracellular antibody probes and streptavidin-conjugated quantum dots in primary neuronal cultures. The neuronal cell culture, the biotinylation protocol and the quantum dot labeling procedures, as well as basic data analysis are discussed.
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Affiliation(s)
- Danielle M Bailey
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Oleg Kovtun
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sandra J Rosenthal
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37235, USA.
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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27
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Gupta R. Self-crowding of AMPA receptors in the excitatory postsynaptic density can effectuate anomalous receptor sub-diffusion. PLoS Comput Biol 2018; 14:e1005984. [PMID: 29444074 PMCID: PMC5812565 DOI: 10.1371/journal.pcbi.1005984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/15/2018] [Indexed: 12/03/2022] Open
Abstract
AMPA receptors (AMPARs) and their associations with auxiliary transmembrane proteins are bulky structures with large steric-exclusion volumes. Hence, self-crowding of AMPARs, depending on the local density, may affect their lateral diffusion in the postsynaptic membrane as well as in the highly crowded postsynaptic density (PSD) at excitatory synapses. Earlier theoretical studies considered only the roles of transmembrane obstacles and the AMPAR-binding submembranous scaffold proteins in shaping receptor diffusion within PSD. Using lattice model of diffusion, the present study investigates the additional impacts of self-crowding on the anomalousity and effective diffusion coefficient (Deff) of AMPAR diffusion. A recursive algorithm for avoiding false self-blocking during diffusion simulation is also proposed. The findings suggest that high density of AMPARs in the obstacle-free membrane itself engenders strongly anomalous diffusion and severe decline in Deff. Adding transmembrane obstacles to the membrane accentuates the anomalousity arising from self-crowding due to the reduced free diffusion space. Contrarily, enhanced AMPAR-scaffold binding, either through increase in binding strength or scaffold density or both, ameliorates the anomalousity resulting from self-crowding. However, binding has differential impacts on Deff depending on the receptor density. Increase in binding causes consistent decrease in Deff for low and moderate receptor density. For high density, binding increases Deff as long as it reduces anomalousity associated with intense self-crowding. Given a sufficiently strong binding condition when diffusion acquires normal behavior, further increase in binding causes decrease in Deff. Supporting earlier experimental observations are mentioned and implications of present findings to the experimental observations on AMPAR diffusion are also drawn. The transmembrane AMPA receptors (AMPARs) prominently exhibit lateral diffusion in the postsynaptic membrane at excitatory synapses. Steric obstructions to AMPAR diffusion due to the crowd of other relatively static transmembrane proteins and binding of AMPARs to the submembranous scaffold proteins in the specialized region of postsynaptic density (PSD) are well known to retard receptor diffusion, which causes receptor trapping and accumulation within PSD. However, AMPARs are significantly bulky structures and may also obstruct their own diffusion paths in the presence of their high density. It is shown here that intense self-crowding of AMPARs may lead to highly obstructed and confined receptor diffusion even in the obstacle-free medium, and the presence of other obstacles further aggravates this effect. AMPAR-scaffold binding reduces confined diffusion arising from self-crowding and strong binding engenders normal diffusion even at high receptor density. However, it overall causes reduction in the effective diffusion coefficient of the receptor diffusion.
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Affiliation(s)
- Rahul Gupta
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
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Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments. NANOMATERIALS 2017; 7:nano7110393. [PMID: 29144410 PMCID: PMC5707610 DOI: 10.3390/nano7110393] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/07/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022]
Abstract
Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples.
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Dynamics of surface neurotransmitter receptors and transporters in glial cells: Single molecule insights. Cell Calcium 2017; 67:46-52. [PMID: 29029790 DOI: 10.1016/j.ceca.2017.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 11/22/2022]
Abstract
The surface dynamics of neurotransmitter receptors and transporters, as well as ion channels, has been well-documented in neurons, revealing complex molecular behaviour and key physiological functions. However, our understanding of the membrane trafficking and dynamics of the signalling molecules located at the plasma membrane of glial cells is still in its infancy. Yet, recent breakthroughs in the field of glial cells have been obtained using combination of superresolution microscopy, single molecule imaging, and electrophysiological recordings. Here, we review our current knowledge on the surface dynamics of neurotransmitter receptors, transporters and ion channels, in glial cells. It has emerged that the brain cell network activity, synaptic activity, and calcium signalling, regulate the surface distribution and dynamics of these molecules. Remarkably, the dynamics of a given neurotransmitter receptor/transporter at the plasma membrane of a glial cell or neuron is unique, revealing the existence of cell-type specific regulatory pathways. Thus, investigating the dynamics of signalling proteins at the surface of glial cells will likely shed new light on our understanding of glial cell physiology and pathology.
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30
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Bannai H. Molecular membrane dynamics: Insights into synaptic function and neuropathological disease. Neurosci Res 2017; 129:47-56. [PMID: 28826905 DOI: 10.1016/j.neures.2017.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/14/2017] [Accepted: 07/26/2017] [Indexed: 11/19/2022]
Abstract
The fluid mosaic model states that molecules in the plasma membrane can freely undergo lateral diffusion; however, in neurons and glia, specific membrane molecules are concentrated in cellular microdomains to overcome the randomizing effects of free diffusion. This specialized distribution of membrane molecules is crucial for various cell functions; one example is the accumulation of neurotransmitter receptors at the postsynaptic neuronal membrane, which enables efficient synaptic transmission. Quantum dot-single particle tracking (QD-SPT) is a super-resolution imaging technique that uses semiconductor nanocrystal quantum dots as fluorescent probes, and is a powerful tool for analyzing protein and lipid behavior in the plasma membrane. In this article, we review studies implementing QD-SPT in neuroscience research and important data gleaned using this technology. Recent QD-SPT experiments have provided critical insights into the mechanism and physiological relevance of membrane self-organization in neurons and astrocytes in the brain. The mobility of some membrane molecules may become abnormal in cellular models of epilepsy and Alzheimer's disease. Based on these findings, we propose that the behavior of membrane molecules reflects the condition of neurons in pathological disease states.
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Affiliation(s)
- Hiroko Bannai
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
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31
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Osakada Y, Zhang K. Single-Particle Tracking Reveals a Dynamic Role of Actin Filaments in Assisting Long-Range Axonal Transport in Neurons. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2017. [DOI: 10.1246/bcsj.20170090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yasuko Osakada
- Department of Chemistry, Stanford University, Stanford, CA 94305 (USA)
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047
| | - Kai Zhang
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, 314 B Roger Adams Laboratory, Urbana, Illinois, 61801 (USA)
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Manshian BB, Martens TF, Kantner K, Braeckmans K, De Smedt SC, Demeester J, Jenkins GJS, Parak WJ, Pelaz B, Doak SH, Himmelreich U, Soenen SJ. The role of intracellular trafficking of CdSe/ZnS QDs on their consequent toxicity profile. J Nanobiotechnology 2017; 15:45. [PMID: 28619032 PMCID: PMC5472855 DOI: 10.1186/s12951-017-0279-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/06/2017] [Indexed: 11/21/2022] Open
Abstract
Background Nanoparticle interactions with cellular membranes and the kinetics of their transport and localization are important determinants of their functionality and their biological consequences. Understanding these phenomena is fundamental for the translation of such NPs from in vitro to in vivo systems for bioimaging and medical applications. Two CdSe/ZnS quantum dots (QD) with differing surface functionality (NH2 or COOH moieties) were used here for investigating the intracellular uptake and transport kinetics of these QDs. Results In water, the COOH- and NH2-QDs were negatively and positively charged, respectively, while in serum-containing medium the NH2-QDs were agglomerated, whereas the COOH-QDs remained dispersed. Though intracellular levels of NH2- and COOH-QDs were very similar after 24 h exposure, COOH-QDs appeared to be continuously internalised and transported by endosomes and lysosomes, while NH2-QDs mainly remained in the lysosomes. The results of (intra)cellular QD trafficking were correlated to their toxicity profiles investigating levels of reactive oxygen species (ROS), mitochondrial ROS, autophagy, changes to cellular morphology and alterations in genes involved in cellular stress, toxicity and cytoskeletal integrity. The continuous flux of COOH-QDs perhaps explains their higher toxicity compared to the NH2-QDs, mainly resulting in mitochondrial ROS and cytoskeletal remodelling which are phenomena that occur early during cellular exposure. Conclusions Together, these data reveal that although cellular QD levels were similar after 24 h, differences in the nature and extent of their cellular trafficking resulted in differences in consequent gene alterations and toxicological effects. Electronic supplementary material The online version of this article (doi:10.1186/s12951-017-0279-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bella B Manshian
- Biomedical NMR Unit/MoSAIC, KU Leuven Campus Gasthuisberg, Herestraat 49, 3000, Louvain, Belgium. .,Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, SA2 8PP, UK.
| | - Thomas F Martens
- Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium.,Center of Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium
| | - Karsten Kantner
- Philipps University of Marburg, Renthof 7, 35032, Marburg, Germany
| | - Kevin Braeckmans
- Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium.,Center of Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium
| | - Stefaan C De Smedt
- Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium
| | - Jo Demeester
- Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, 9000, Ghent, Belgium
| | - Gareth J S Jenkins
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, SA2 8PP, UK
| | - Wolfgang J Parak
- Philipps University of Marburg, Renthof 7, 35032, Marburg, Germany.,CICBiomagune, San Sebastian, Spain
| | - Beatriz Pelaz
- Philipps University of Marburg, Renthof 7, 35032, Marburg, Germany
| | - Shareen H Doak
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, SA2 8PP, UK
| | - Uwe Himmelreich
- Biomedical NMR Unit/MoSAIC, KU Leuven Campus Gasthuisberg, Herestraat 49, 3000, Louvain, Belgium
| | - Stefaan J Soenen
- Biomedical NMR Unit/MoSAIC, KU Leuven Campus Gasthuisberg, Herestraat 49, 3000, Louvain, Belgium
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33
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Astrocyte-to-neuron communication through integrin-engaged Thy-1/CBP/Csk/Src complex triggers neurite retraction via the RhoA/ROCK pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:243-254. [DOI: 10.1016/j.bbamcr.2016.11.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/27/2016] [Accepted: 11/07/2016] [Indexed: 12/22/2022]
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34
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Kairdolf BA, Qian X, Nie S. Bioconjugated Nanoparticles for Biosensing, in Vivo Imaging, and Medical Diagnostics. Anal Chem 2017; 89:1015-1031. [DOI: 10.1021/acs.analchem.6b04873] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Brad A. Kairdolf
- Department of Biomedical
Engineering, Emory University and Georgia Institute of Technology, 1760 Haygood Drive, Atlanta, Georgia 30322, United States
| | - Ximei Qian
- Department of Biomedical
Engineering, Emory University and Georgia Institute of Technology, 1760 Haygood Drive, Atlanta, Georgia 30322, United States
| | - Shuming Nie
- Department of Biomedical
Engineering, Emory University and Georgia Institute of Technology, 1760 Haygood Drive, Atlanta, Georgia 30322, United States
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35
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Hu J, Wang ZY, Li CC, Zhang CY. Advances in single quantum dot-based nanosensors. Chem Commun (Camb) 2017; 53:13284-13295. [DOI: 10.1039/c7cc07752a] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We review the advances in single quantum dot-based nanosensors and their biomedical applications. We highlight their challenges and future direction.
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Affiliation(s)
- Juan Hu
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Zi-yue Wang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Chen-chen Li
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
| | - Chun-yang Zhang
- College of Chemistry
- Chemical Engineering and Materials Science
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong
- Key Laboratory of Molecular and Nano Probes
- Ministry of Education
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36
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Varela JA, Ferreira JS, Dupuis JP, Durand P, Bouchet D, Groc L. Single nanoparticle tracking of [Formula: see text]-methyl-d-aspartate receptors in cultured and intact brain tissue. NEUROPHOTONICS 2016; 3:041808. [PMID: 27429996 PMCID: PMC4940612 DOI: 10.1117/1.nph.3.4.041808] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/22/2016] [Indexed: 06/01/2023]
Abstract
Recent developments in single-molecule imaging have revealed many biological mechanisms, providing high spatial and temporal resolution maps of molecular events. In neurobiology, these techniques unveiled that plasma membrane neurotransmitter receptors and transporters laterally diffuse at the surface of cultured brain cells. The photostability of bright nanoprobes, such as quantum dots (QDs), has given access to neurotransmitter receptor tracking over long periods of time with a high spatial resolution. However, our knowledge has been restricted to cultured systems, i.e., neurons and organotypic slices, therefore lacking several aspects of the intact brain rheology and connectivity. Here, we used QDs to track single glutamatergic [Formula: see text]-methyl-d-aspartate receptors (NMDAR) in acute brain slices. By delivering functionalized nanoparticles in vivo through intraventricular injections to rats expressing genetically engineered-tagged NMDAR, we successfully tracked the receptors in native brain tissue. Comparing NMDAR tracking to different classical brain preparations (acute brain slices, cultured organotypic brain slices, and cultured neurons) revealed that the surface diffusion properties shared several features and are also influenced by the nature of the extracellular environment. Together, we describe the experimental procedures to track plasma membrane NMDAR in dissociated and native brain tissue, paving the way for investigations aiming at characterizing receptor diffusion biophysics in intact tissue and exploring the physiopathological roles of receptor surface dynamics.
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Affiliation(s)
- Juan A. Varela
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Joana S. Ferreira
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Julien P. Dupuis
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Pauline Durand
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Delphine Bouchet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Laurent Groc
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 146 rue Leo Saignat, 33077 Bordeaux, France
- Centre National de la Recherche Scientifique, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
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Protein Crowding within the Postsynaptic Density Can Impede the Escape of Membrane Proteins. J Neurosci 2016; 36:4276-95. [PMID: 27076425 DOI: 10.1523/jneurosci.3154-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 02/19/2016] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED Mechanisms regulating lateral diffusion and positioning of glutamate receptors within the postsynaptic density (PSD) determine excitatory synaptic strength. Scaffold proteins in the PSD are abundant receptor binding partners, yet electron microscopy suggests that the PSD is highly crowded, potentially restricting the diffusion of receptors regardless of binding. However, the contribution of macromolecular crowding to receptor retention remains poorly understood. We combined experimental and computational approaches to test the effect of synaptic crowding on receptor movement and positioning in Sprague Dawley rat hippocampal neurons. We modeled AMPA receptor diffusion in synapses where the distribution of scaffold proteins was determined from photoactivated localization microscopy experiments, and receptor-scaffold association and dissociation rates were adjusted to fit single-molecule tracking and fluorescence recovery measurements. Simulations predicted that variation of receptor size strongly influences the fractional synaptic area the receptor may traverse, and the proportion that may exchange in and out of the synapse. To test the model experimentally, we designed a set of novel transmembrane (TM) probes. A single-pass TM protein with one PDZ binding motif concentrated in the synapse as do AMPARs yet was more mobile there than the much larger AMPAR. Furthermore, either the single binding motif or an increase in cytoplasmic bulk through addition of a single GFP slowed synaptic movement of a small TM protein. These results suggest that both crowding and binding limit escape of AMPARs from the synapse. Moreover, tight protein packing within the PSD may modulate the synaptic dwell time of many TM proteins important for synaptic function. SIGNIFICANCE STATEMENT Small alterations to the distribution within synapses of key transmembrane proteins, such as receptors, can dramatically change synaptic strength. Indeed, many diseases are thought to unbalance neural circuit function in this manner. Processes that regulate this in healthy synapses are unclear, however. By combining computer simulations with imaging methods that examined protein dynamics at multiple scales in space and time, we showed that both steric effects and protein-protein binding each regulate the mobility of receptors in the synapse. Our findings extend our knowledge of the synapse as a crowded environment that counteracts molecular diffusion, and support the idea that both molecular collisions and biochemical binding can be involved in the regulation of neural circuit performance.
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38
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Sokoll S, Prokazov Y, Hanses M, Biermann B, Tönnies K, Heine M. Fast Three-Dimensional Single-Particle Tracking in Natural Brain Tissue. Biophys J 2016; 109:1463-71. [PMID: 26445447 DOI: 10.1016/j.bpj.2015.07.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/15/2015] [Accepted: 07/31/2015] [Indexed: 11/18/2022] Open
Abstract
Observation of molecular dynamics is often biased by the optical very heterogeneous environment of cells and complex tissue. Here, we have designed an algorithm that facilitates molecular dynamic analyses within brain slices. We adjust fast astigmatism-based three-dimensional single-particle tracking techniques to depth-dependent optical aberrations induced by the refractive index mismatch so that they are applicable to complex samples. In contrast to existing techniques, our online calibration method determines the aberration directly from the acquired two-dimensional image stream by exploiting the inherent particle movement and the redundancy introduced by the astigmatism. The method improves the positioning by reducing the systematic errors introduced by the aberrations, and allows correct derivation of the cellular morphology and molecular diffusion parameters in three dimensions independently of the imaging depth. No additional experimental effort for the user is required. Our method will be useful for many imaging configurations, which allow imaging in deep cellular structures.
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Affiliation(s)
- Stefan Sokoll
- Research Group for Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Research Group for Image Processing and Pattern Recognition, Otto-von-Guericke University, Magdeburg, Germany
| | - Yury Prokazov
- Special Lab for Electron and Laserscanning Microscopy, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Magnus Hanses
- Research Group for Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Barbara Biermann
- Research Group for Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Institute of Neural and Sensory Physiology, Medical Faculty, University of Düsseldorf, Germany
| | - Klaus Tönnies
- Research Group for Image Processing and Pattern Recognition, Otto-von-Guericke University, Magdeburg, Germany
| | - Martin Heine
- Research Group for Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany.
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Coumans JVF, Palanisamy SKA, McFarlane J, Moens PDJ. Proteomic and Microscopic Strategies towards the Analysis of the Cytoskeletal Networks in Major Neuropsychiatric Disorders. Int J Mol Sci 2016; 17:E581. [PMID: 27104521 PMCID: PMC4849037 DOI: 10.3390/ijms17040581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 11/17/2022] Open
Abstract
Mental health disorders have become worldwide health priorities. It is estimated that in the next 20 years they will account for a 16 trillion United State dollars (US$) loss. Up to now, the underlying pathophysiology of psychiatric disorders remains elusive. Altered cytoskeleton proteins expression that may influence the assembly, organization and maintenance of cytoskeletal integrity has been reported in major depressive disorders, schizophrenia and to some extent bipolar disorders. The use of quantitative proteomics, dynamic microscopy and super-resolution microscopy to investigate disease-specific protein signatures holds great promise to improve our understanding of these disorders. In this review, we present the currently available quantitative proteomic approaches use in neurology, gel-based, stable isotope-labelling and label-free methodologies and evaluate their strengths and limitations. We also reported on enrichment/subfractionation methods that target the cytoskeleton associated proteins and discuss the need of alternative methods for further characterization of the neurocytoskeletal proteome. Finally, we present live cell imaging approaches and emerging dynamic microscopy technology that will provide the tools necessary to investigate protein interactions and their dynamics in the whole cells. While these areas of research are still in their infancy, they offer huge potential towards the understanding of the neuronal network stability and its modification across neuropsychiatric disorders.
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Affiliation(s)
- Joëlle V F Coumans
- School of Rural Medicine, University of New England, Armidale, NSW 2351, Australia.
| | - Suresh K A Palanisamy
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
| | - Jim McFarlane
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
| | - Pierre D J Moens
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
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40
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Mapping the dynamics and nanoscale organization of synaptic adhesion proteins using monomeric streptavidin. Nat Commun 2016; 7:10773. [PMID: 26979420 PMCID: PMC4799371 DOI: 10.1038/ncomms10773] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 01/17/2016] [Indexed: 12/12/2022] Open
Abstract
The advent of super-resolution imaging (SRI) has created a need for optimized labelling strategies. We present a new method relying on fluorophore-conjugated monomeric streptavidin (mSA) to label membrane proteins carrying a short, enzymatically biotinylated tag, compatible with SRI techniques including uPAINT, STED and dSTORM. We demonstrate efficient and specific labelling of target proteins in confined intercellular and organotypic tissues, with reduced steric hindrance and no crosslinking compared with multivalent probes. We use mSA to decipher the dynamics and nanoscale organization of the synaptic adhesion molecules neurexin-1β, neuroligin-1 (Nlg1) and leucine-rich-repeat transmembrane protein 2 (LRRTM2) in a dual-colour configuration with GFP nanobody, and show that these proteins are diffusionally trapped at synapses where they form apposed trans-synaptic adhesive structures. Furthermore, Nlg1 is dynamic, disperse and sensitive to synaptic stimulation, whereas LRRTM2 is organized in compact and stable nanodomains. Thus, mSA is a versatile tool to image membrane proteins at high resolution in complex live environments, providing novel information about the nano-organization of biological structures. The advent of fluorescence-based super-resolution microscopy has created a need for labeling strategies relying on small probes that minimally perturb protein function. Here the authors describe a labeling method that reduces protein tag and label sizes, allowing for accurate protein targeting and measurements of protein dynamics in tight cellular spaces.
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41
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Varela JA, Dupuis JP, Etchepare L, Espana A, Cognet L, Groc L. Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices. Nat Commun 2016; 7:10947. [PMID: 26971573 PMCID: PMC4793083 DOI: 10.1038/ncomms10947] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/03/2016] [Indexed: 02/01/2023] Open
Abstract
Single-molecule imaging has changed the way we understand many biological mechanisms, particularly in neurobiology, by shedding light on intricate molecular events down to the nanoscale. However, current single-molecule studies in neuroscience have been limited to cultured neurons or organotypic slices, leaving as an open question the existence of fast receptor diffusion in intact brain tissue. Here, for the first time, we targeted dopamine receptors in vivo with functionalized quantum dots and were able to perform single-molecule tracking in acute rat brain slices. We propose a novel delocalized and non-inflammatory way of delivering nanoparticles (NPs) in vivo to the brain, which allowed us to label and track genetically engineered surface dopamine receptors in neocortical neurons, revealing inherent behaviour and receptor activity regulations. We thus propose a NP-based platform for single-molecule studies in the living brain, opening new avenues of research in physiological and pathological animal models.
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Affiliation(s)
- Juan A Varela
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux F-33000, France.,CNRS, IINS UMR 5297, Bordeaux F-33000, France
| | - Julien P Dupuis
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux F-33000, France.,CNRS, IINS UMR 5297, Bordeaux F-33000, France
| | - Laetitia Etchepare
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux F-33000, France.,CNRS, IINS UMR 5297, Bordeaux F-33000, France
| | - Agnès Espana
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux F-33000, France.,CNRS, IINS UMR 5297, Bordeaux F-33000, France
| | - Laurent Cognet
- University of Bordeaux, LP2 NUMR 5298, Talence F-33405, France.,Institut d'Optique &CNRS, LP2NUMR 5298, Talence F-33405, France
| | - Laurent Groc
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux F-33000, France.,CNRS, IINS UMR 5297, Bordeaux F-33000, France
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Abstract
UNLABELLED Synapses depend on trafficking of key membrane proteins by lateral diffusion from surface populations and by exocytosis from intracellular pools. The cell adhesion molecule neurexin (Nrxn) plays essential roles in synapses, but the dynamics and regulation of its trafficking are unknown. Here, we performed single-particle tracking and live imaging of transfected, epitope-tagged Nrxn variants in cultured rat and mouse wild-type or knock-out neurons. We observed that structurally larger αNrxn molecules are more mobile in the plasma membrane than smaller βNrxns because αNrxns displayed higher diffusion coefficients in extrasynaptic regions and excitatory or inhibitory terminals. We found that well characterized interactions with extracellular binding partners regulate the surface mobility of Nrxns. Binding to neurexophilin-1 (Nxph1) reduced the surface diffusion of αNrxns when both molecules were coexpressed. Conversely, impeding other interactions by insertion of splice sequence #4 or removal of extracellular Ca(2+) augmented the mobility of αNrxns and βNrxns. We also determined that fast axonal transport delivers Nrxns to the neuronal surface because Nrxns comigrate as cargo on synaptic vesicle protein transport vesicles (STVs). Unlike surface mobility, intracellular transport of βNrxn(+) STVs was faster than that of αNrxns, but both depended on the microtubule motor protein KIF1A and neuronal activity regulated the velocity. Large spontaneous fusion of Nrxn(+) STVs occurred simultaneously with synaptophysin on axonal membranes mostly outside of active presynaptic terminals. Surface Nrxns enriched at synaptic terminals where αNrxns and Nxph1/αNrxns recruited GABAAR subunits. Therefore, our results identify regulated dynamic trafficking as an important property of Nrxns that corroborates their function at synapses. SIGNIFICANCE STATEMENT Synapses mediate most functions in our brains and depend on the precise and timely delivery of key molecules throughout life. Neurexins (Nrxns) are essential synaptic cell adhesion molecules that are involved in synaptic transmission and differentiation of synaptic contacts. In addition, Nrxns have been linked to neuropsychiatric diseases such as autism. Because little is known about the dynamic aspects of trafficking of neurexins to synapses, we investigated this important question using single-molecule tracking and time-lapse imaging. We identify distinct differences between major Nrxn variants both in surface mobility and during intracellular transport. Because their dynamic behavior is highly regulated, for example, by different binding activities, these processes have immediate consequences for the function of Nrxns at synapses.
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Mal J, Nancharaiah YV, van Hullebusch ED, Lens PNL. Metal chalcogenide quantum dots: biotechnological synthesis and applications. RSC Adv 2016. [DOI: 10.1039/c6ra08447h] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metal chalcogenide (metal sulfide, selenide and telluride) quantum dots (QDs) have attracted considerable attention due to their quantum confinement and size-dependent photoemission characteristics.
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Affiliation(s)
- J. Mal
- UNESCO-IHE
- Delft
- The Netherlands
- Biofouling and Biofilm Process Section
- Water and Steam Chemistry Division
| | - Y. V. Nancharaiah
- UNESCO-IHE
- Delft
- The Netherlands
- Université Paris-Est
- Laboratoire Géomatériaux et Environnement (LGE)
| | - E. D. van Hullebusch
- Biofouling and Biofilm Process Section
- Water and Steam Chemistry Division
- Bhabha Atomic Research Centre
- Kalpakkam-603102
- India
| | - P. N. L. Lens
- UNESCO-IHE
- Delft
- The Netherlands
- Department of Chemistry and Bioengineering
- Tampere University of Technology
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44
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Heller JP, Rusakov DA. Morphological plasticity of astroglia: Understanding synaptic microenvironment. Glia 2015; 63:2133-51. [PMID: 25782611 PMCID: PMC4737250 DOI: 10.1002/glia.22821] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 03/02/2015] [Indexed: 12/27/2022]
Abstract
Memory formation in the brain is thought to rely on the remodeling of synaptic connections which eventually results in neural network rewiring. This remodeling is likely to involve ultrathin astroglial protrusions which often occur in the immediate vicinity of excitatory synapses. The phenomenology, cellular mechanisms, and causal relationships of such astroglial restructuring remain, however, poorly understood. This is in large part because monitoring and probing of the underpinning molecular machinery on the scale of nanoscopic astroglial compartments remains a challenge. Here we briefly summarize the current knowledge regarding the cellular organisation of astroglia in the synaptic microenvironment and discuss molecular mechanisms potentially involved in use-dependent astroglial morphogenesis. We also discuss recent observations concerning morphological astroglial plasticity, the respective monitoring methods, and some of the newly emerging techniques that might help with conceptual advances in the area.
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Affiliation(s)
- Janosch P Heller
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Dmitri A Rusakov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
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45
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Manzo C, Garcia-Parajo MF. A review of progress in single particle tracking: from methods to biophysical insights. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:124601. [PMID: 26511974 DOI: 10.1088/0034-4885/78/12/124601] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Optical microscopy has for centuries been a key tool to study living cells with minimum invasiveness. The advent of single molecule techniques over the past two decades has revolutionized the field of cell biology by providing a more quantitative picture of the complex and highly dynamic organization of living systems. Amongst these techniques, single particle tracking (SPT) has emerged as a powerful approach to study a variety of dynamic processes in life sciences. SPT provides access to single molecule behavior in the natural context of living cells, thereby allowing a complete statistical characterization of the system under study. In this review we describe the foundations of SPT together with novel optical implementations that nowadays allow the investigation of single molecule dynamic events with increasingly high spatiotemporal resolution using molecular densities closer to physiological expression levels. We outline some of the algorithms for the faithful reconstruction of SPT trajectories as well as data analysis, and highlight biological examples where the technique has provided novel insights into the role of diffusion regulating cellular function. The last part of the review concentrates on different theoretical models that describe anomalous transport behavior and ergodicity breaking observed from SPT studies in living cells.
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Affiliation(s)
- Carlo Manzo
- ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
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46
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Massey M, Wu M, Conroy EM, Algar WR. Mind your P's and Q's: the coming of age of semiconducting polymer dots and semiconductor quantum dots in biological applications. Curr Opin Biotechnol 2015; 34:30-40. [DOI: 10.1016/j.copbio.2014.11.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/06/2014] [Indexed: 01/15/2023]
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47
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Tsou CJ, Hsia CH, Chu JY, Hung Y, Chen YP, Chien FC, Chou KC, Chen P, Mou CY. Local pH tracking in living cells. NANOSCALE 2015; 7:4217-4225. [PMID: 25672786 DOI: 10.1039/c4nr06545j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ∼10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which provides much needed information for designing an efficient drug delivery nanosystem.
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Affiliation(s)
- Chieh-Jui Tsou
- Department of Chemistry, National Taiwan University, Taipei, Taiwan 106.
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48
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Wegner KD, Hildebrandt N. Quantum dots: bright and versatile in vitro and in vivo fluorescence imaging biosensors. Chem Soc Rev 2015; 44:4792-4834. [DOI: 10.1039/c4cs00532e] [Citation(s) in RCA: 556] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Colourful cells and tissues: semiconductor quantum dots and their versatile applications in multiplexed bioimaging research.
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Affiliation(s)
- K. David Wegner
- NanoBioPhotonics
- Institut d'Electronique Fondamentale
- Université Paris-Sud
- 91405 Orsay Cedex
- France
| | - Niko Hildebrandt
- NanoBioPhotonics
- Institut d'Electronique Fondamentale
- Université Paris-Sud
- 91405 Orsay Cedex
- France
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49
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Lauer FM, Kaemmerer E, Meckel T. Single molecule microscopy in 3D cell cultures and tissues. Adv Drug Deliv Rev 2014; 79-80:79-94. [PMID: 25453259 DOI: 10.1016/j.addr.2014.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/20/2014] [Accepted: 10/03/2014] [Indexed: 12/19/2022]
Abstract
From the onset of the first microscopic visualization of single fluorescent molecules in living cells at the beginning of this century, to the present, almost routine application of single molecule microscopy, the method has well-proven its ability to contribute unmatched detailed insight into the heterogeneous and dynamic molecular world life is composed of. Except for investigations on bacteria and yeast, almost the entire story of success is based on studies on adherent mammalian 2D cell cultures. However, despite this continuous progress, the technique was not able to keep pace with the move of the cell biology community to adapt 3D cell culture models for basic research, regenerative medicine, or drug development and screening. In this review, we will summarize the progress, which only recently allowed for the application of single molecule microscopy to 3D cell systems and give an overview of the technical advances that led to it. While initially posing a challenge, we finally conclude that relevant 3D cell models will become an integral part of the on-going success of single molecule microscopy.
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Affiliation(s)
- Florian M Lauer
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany
| | - Elke Kaemmerer
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany; Institute of Health and Biomedical Innovation, Science and Engineering Faculty, Queensland University of Technology, 60 Musk Ave, Kelvin Grove, 4059 QLD, Brisbane, Australia
| | - Tobias Meckel
- Membrane Dynamics, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany.
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50
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He X, Ma N. An overview of recent advances in quantum dots for biomedical applications. Colloids Surf B Biointerfaces 2014; 124:118-31. [DOI: 10.1016/j.colsurfb.2014.06.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/23/2014] [Accepted: 06/01/2014] [Indexed: 12/23/2022]
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