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Teixeira P, Galland R, Chevrollier A. Super-resolution microscopies, technological breakthrough to decipher mitochondrial structure and dynamic. Semin Cell Dev Biol 2024; 159-160:38-51. [PMID: 38310707 DOI: 10.1016/j.semcdb.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/08/2024] [Accepted: 01/25/2024] [Indexed: 02/06/2024]
Abstract
Mitochondria are complex organelles with an outer membrane enveloping a second inner membrane that creates a vast matrix space partitioned by pockets or cristae that join the peripheral inner membrane with several thin junctions. Several micrometres long, mitochondria are generally close to 300 nm in diameter, with membrane layers separated by a few tens of nanometres. Ultrastructural data from electron microscopy revealed the structure of these mitochondria, while conventional optical microscopy revealed their extraordinary dynamics through fusion, fission, and migration processes but its limited resolution power restricted the possibility to go further. By overcoming the limits of light diffraction, Super-Resolution Microscopy (SRM) now offers the potential to establish the links between the ultrastructure and remodelling of mitochondrial membranes, leading to major advances in our understanding of mitochondria's structure-function. Here we review the contributions of SRM imaging to our understanding of the relationship between mitochondrial structure and function. What are the hopes for these new imaging approaches which are particularly important for mitochondrial pathologies?
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Affiliation(s)
- Pauline Teixeira
- Univ. Angers, INSERM, CNRS, MITOVASC, Equipe MITOLAB, SFR ICAT, F-49000 Angers, France
| | - Rémi Galland
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - Arnaud Chevrollier
- Univ. Angers, INSERM, CNRS, MITOVASC, Equipe MITOLAB, SFR ICAT, F-49000 Angers, France.
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2
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Xu X, Qiu K, Tian Z, Aryal C, Rowan F, Chen R, Sun Y, Diao J. Probing the dynamic crosstalk of lysosomes and mitochondria with structured illumination microscopy. Trends Analyt Chem 2023; 169:117370. [PMID: 37928815 PMCID: PMC10621629 DOI: 10.1016/j.trac.2023.117370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Structured illumination microscopy (SIM) is a super-resolution technology for imaging living cells and has been used for studying the dynamics of lysosomes and mitochondria. Recently, new probes and analyzing methods have been developed for SIM imaging, enabling the quantitative analysis of these subcellular structures and their interactions. This review provides an overview of the working principle and advances of SIM, as well as the organelle-targeting principles and types of fluorescence probes, including small molecules, metal complexes, nanoparticles, and fluorescent proteins. Additionally, quantitative methods based on organelle morphology and distribution are outlined. Finally, the review provides an outlook on the current challenges and future directions for improving the combination of SIM imaging and image analysis to further advance the study of organelles. We hope that this review will be useful for researchers working in the field of organelle research and help to facilitate the development of SIM imaging and analysis techniques.
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Affiliation(s)
- Xiuqiong Xu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kangqiang Qiu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Zhiqi Tian
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Chinta Aryal
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Fiona Rowan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Rui Chen
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Yujie Sun
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
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3
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Tokuyama T, Yanagi S. Role of Mitochondrial Dynamics in Heart Diseases. Genes (Basel) 2023; 14:1876. [PMID: 37895224 PMCID: PMC10606177 DOI: 10.3390/genes14101876] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
Mitochondrial dynamics, including fission and fusion processes, are essential for heart health. Mitochondria, the powerhouses of cells, maintain their integrity through continuous cycles of biogenesis, fission, fusion, and degradation. Mitochondria are relatively immobile in the adult heart, but their morphological changes due to mitochondrial morphology factors are critical for cellular functions such as energy production, organelle integrity, and stress response. Mitochondrial fusion proteins, particularly Mfn1/2 and Opa1, play multiple roles beyond their pro-fusion effects, such as endoplasmic reticulum tethering, mitophagy, cristae remodeling, and apoptosis regulation. On the other hand, the fission process, regulated by proteins such as Drp1, Fis1, Mff and MiD49/51, is essential to eliminate damaged mitochondria via mitophagy and to ensure proper cell division. In the cardiac system, dysregulation of mitochondrial dynamics has been shown to cause cardiac hypertrophy, heart failure, ischemia/reperfusion injury, and various cardiac diseases, including metabolic and inherited cardiomyopathies. In addition, mitochondrial dysfunction associated with oxidative stress has been implicated in atherosclerosis, hypertension and pulmonary hypertension. Therefore, understanding and regulating mitochondrial dynamics is a promising therapeutic tool in cardiac diseases. This review summarizes the role of mitochondrial morphology in heart diseases for each mitochondrial morphology regulatory gene, and their potential as therapeutic targets to heart diseases.
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Affiliation(s)
- Takeshi Tokuyama
- Division of Regenerative Medicine, Center for Molecular Medicine, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan
| | - Shigeru Yanagi
- Laboratory of Molecular Biochemistry, Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo 171-0031, Japan;
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4
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Samanta K, Ahmad A, Tinguely JC, Ahluwalia BS, Joseph J. Transmission structured illumination microscopy with tunable frequency illumination using tilt mirror assembly. Sci Rep 2023; 13:1453. [PMID: 36702876 PMCID: PMC9879979 DOI: 10.1038/s41598-023-27814-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 01/09/2023] [Indexed: 01/27/2023] Open
Abstract
We present experimental demonstration of tilt-mirror assisted transmission structured illumination microscopy (tSIM) that offers a large field of view super resolution imaging. An assembly of custom-designed tilt-mirrors are employed as the illumination module where the sample is excited with the interference of two beams reflected from the opposite pair of mirror facets. Tunable frequency structured patterns are generated by changing the mirror-tilt angle and the hexagonal-symmetric arrangement is considered for the isotropic resolution in three orientations. Utilizing high numerical aperture (NA) objective in standard SIM provides super-resolution compromising with the field-of-view (FOV). Employing low NA (20X/0.4) objective lens detection, we experimentally demonstrate [Formula: see text] (0.56 mm[Formula: see text]0.35 mm) size single FOV image with [Formula: see text]1.7- and [Formula: see text]2.4-fold resolution improvement (exploiting various illumination by tuning tilt-mirrors) over the diffraction limit. The results are verified both for the fluorescent beads as well as biological samples. The tSIM geometry decouples the illumination and the collection light paths consequently enabling free change of the imaging objective lens without influencing the spatial frequency of the illumination pattern that are defined by the tilt-mirrors. The large and scalable FOV supported by tSIM will find usage for applications where scanning large areas are necessary as in pathology and applications where images must be correlated both in space and time.
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Affiliation(s)
- Krishnendu Samanta
- grid.417967.a0000 0004 0558 8755Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016 India ,grid.10919.300000000122595234Department of Physics and Technology, UiT-The Arctic University of Norway, 9037 Tromsö, Norway
| | - Azeem Ahmad
- grid.10919.300000000122595234Department of Physics and Technology, UiT-The Arctic University of Norway, 9037 Tromsö, Norway
| | - Jean-Claude Tinguely
- grid.10919.300000000122595234Department of Physics and Technology, UiT-The Arctic University of Norway, 9037 Tromsö, Norway
| | - Balpreet Singh Ahluwalia
- grid.10919.300000000122595234Department of Physics and Technology, UiT-The Arctic University of Norway, 9037 Tromsö, Norway
| | - Joby Joseph
- grid.417967.a0000 0004 0558 8755Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016 India ,grid.417967.a0000 0004 0558 8755Optics and Photonics Centre, Indian Institute of Technology Delhi, New Delhi, 110016 India
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5
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Calì T, Brini M. Quantification of organelle contact sites by split-GFP-based contact site sensors (SPLICS) in living cells. Nat Protoc 2021; 16:5287-5308. [PMID: 34686857 DOI: 10.1038/s41596-021-00614-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 08/09/2021] [Indexed: 02/08/2023]
Abstract
Membrane contact sites between organelles are essential for maintaining cellular homeostasis, which requires the continuous exchange of signaling molecules, ions, nutrients and lipids. Alterations of different contact sites are associated with a wide spectrum of human diseases. However, visualizing and quantifying these contact sites remains a challenge. This protocol describes the use of split-GFP-based contact site sensors (SPLICS) in microscopy applications for mapping organelle contact sites both in fixed and living cells. SPLICS sensors are engineered to express equimolar amounts of the organelle-targeted nonfluorescent β11 and GFP1-10 portions of the split-GFP protein in a single vector, and are capable of reconstituting fluorescence when two opposing membranes come into proximity. Reconstitution will occur only over the cell volume at defined contact sites resulting in a bright signal that can be detected easily and quantified automatically with specific custom-made plugins. The use of minimal targeting sequences facilitates targeting specificity and membrane coverage, avoiding artifacts due to full-length fusion protein overexpression and, thus, possible perturbations of the cell's physiology. SPLICS sensors engineered to simultaneously detect multiple contact sites within the same cell have been generated by exploiting the ability of the β11 GFP fragment to reconstitute different color-shifted variants of the GFP1-10 fragment. Here, we describe a detailed protocol to set up SPLICS expression in living cells (2-3 d), detection and acquisition (1 d), and automated quantification with custom plugins (1-2 d). We also advise on construct design and characterization for novel organelle contacts.
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Affiliation(s)
- Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Padua Neuroscience Center (PNC), University of Padua, Padua, Italy.
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
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6
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Chen J, Fu Z, Chen B, Chen SC. Fast 3D super-resolution imaging using a digital micromirror device and binary holography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210193R. [PMID: 34775694 PMCID: PMC8590196 DOI: 10.1117/1.jbo.26.11.116502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE High-speed three-dimensional (3D) super-resolution microscopy is a unique tool to investigate various biological phenomena; yet the technology is not broadly adopted due to its high cost and complex system design. AIM We present a compact, low-cost, and high-speed 3D structured illumination microscopy (SIM) based on a digital micromirror device and binary holography to visualize fast biological events with super-resolution. APPROACH The 3D SIM uses a digital micromirror device to generate three laser foci with individually controllable positions, phases, and amplitudes via binary holography at the back aperture of objective lens to form optimal 3D structured patterns. Fifteen raw images are sequentially recorded and processed by the 3D SIM algorithm to reconstruct a super-resolved image. RESULTS Super-resolution 3D imaging at a speed of 26.7 frames per second is achieved with a lateral and axial resolution of 155 and 487 nm, which corresponds to a 1.65- and 1.63-times resolution enhancement, respectively, comparing with standard deconvolution microscopy. CONCLUSIONS The 3D SIM realizes fast super-resolution imaging with optimal 3D structured illumination, which may find important applications in biophotonics.
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Affiliation(s)
- Jialong Chen
- The Chinese University of Hong Kong, Department of Mechanical and Automation Engineering, Shatin, Hong Kong
| | - Zhiqiang Fu
- The Chinese University of Hong Kong, Department of Mechanical and Automation Engineering, Shatin, Hong Kong
| | - Bingxu Chen
- The Chinese University of Hong Kong, Department of Mechanical and Automation Engineering, Shatin, Hong Kong
| | - Shih-Chi Chen
- The Chinese University of Hong Kong, Department of Mechanical and Automation Engineering, Shatin, Hong Kong
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7
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Jing Y, Zhang C, Yu B, Lin D, Qu J. Super-Resolution Microscopy: Shedding New Light on In Vivo Imaging. Front Chem 2021; 9:746900. [PMID: 34595156 PMCID: PMC8476955 DOI: 10.3389/fchem.2021.746900] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 08/26/2021] [Indexed: 12/28/2022] Open
Abstract
Over the past two decades, super-resolution microscopy (SRM), which offered a significant improvement in resolution over conventional light microscopy, has become a powerful tool to visualize biological activities in both fixed and living cells. However, completely understanding biological processes requires studying cells in a physiological context at high spatiotemporal resolution. Recently, SRM has showcased its ability to observe the detailed structures and dynamics in living species. Here we summarized recent technical advancements in SRM that have been successfully applied to in vivo imaging. Then, improvements in the labeling strategies are discussed together with the spectroscopic and chemical demands of the fluorophores. Finally, we broadly reviewed the current applications for super-resolution techniques in living species and highlighted some inherent challenges faced in this emerging field. We hope that this review could serve as an ideal reference for researchers as well as beginners in the relevant field of in vivo super resolution imaging.
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Affiliation(s)
| | | | | | - Danying Lin
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
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8
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Khamsing D, Lebrun S, Fanget I, Larochette N, Tourain C, de Sars V, Brunstein M, Oheim M, Carrel D, Darchen F, Desnos C. A role for BDNF- and NMDAR-induced lysosomal recruitment of mTORC1 in the regulation of neuronal mTORC1 activity. Mol Brain 2021; 14:112. [PMID: 34247625 PMCID: PMC8273036 DOI: 10.1186/s13041-021-00820-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
Memory and long term potentiation require de novo protein synthesis. A key regulator of this process is mTORC1, a complex comprising the mTOR kinase. Growth factors activate mTORC1 via a pathway involving PI3-kinase, Akt, the TSC complex and the GTPase Rheb. In non-neuronal cells, translocation of mTORC1 to late endocytic compartments (LEs), where Rheb is enriched, is triggered by amino acids. However, the regulation of mTORC1 in neurons remains unclear. In mouse hippocampal neurons, we observed that BDNF and treatments activating NMDA receptors trigger a robust increase in mTORC1 activity. NMDA receptors activation induced a significant recruitment of mTOR onto lysosomes even in the absence of external amino acids, whereas mTORC1 was evenly distributed in neurons under resting conditions. NMDA receptor-induced mTOR translocation to LEs was partly dependent on the BDNF receptor TrkB, suggesting that BDNF contributes to the effect of NMDA receptors on mTORC1 translocation. In addition, the combination of Rheb overexpression and artificial mTORC1 targeting to LEs by means of a modified component of mTORC1 fused with a LE-targeting motif strongly activated mTOR. To gain spatial and temporal control over mTOR localization, we designed an optogenetic module based on light-sensitive dimerizers able to recruit mTOR on LEs. In cells expressing this optogenetic tool, mTOR was translocated to LEs upon photoactivation. In the absence of growth factor, this was not sufficient to activate mTORC1. In contrast, mTORC1 was potently activated by a combination of BDNF and photoactivation. The data demonstrate that two important triggers of synaptic plasticity, BDNF and NMDA receptors, synergistically power the two arms of the mTORC1 activation mechanism, i.e., mTORC1 translocation to LEs and Rheb activation. Moreover, they unmask a functional link between NMDA receptors and mTORC1 that could underlie the changes in the synaptic proteome associated with long-lasting changes in synaptic strength.
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Affiliation(s)
- Dany Khamsing
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France
| | - Solène Lebrun
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France
| | - Isabelle Fanget
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France
| | - Nathanaël Larochette
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France.,Université de Paris, Centre National de la Recherche Scientifique, INSERM, B3OA, Paris, France, Ecole Nationale Vétérinaire d'Alfort, B3OA, Maisons-Alfort, France
| | - Christophe Tourain
- Wavefront-Engineering Microscopy Group, Sorbonne Université, INSERM S968, CNRS UMR7210, Institut de la Vision, Paris, France
| | - Vincent de Sars
- Wavefront-Engineering Microscopy Group, Sorbonne Université, INSERM S968, CNRS UMR7210, Institut de la Vision, Paris, France
| | - Maia Brunstein
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France
| | - Martin Oheim
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France
| | - Damien Carrel
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France.
| | - François Darchen
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France.,Service de Psychiatrie Infanto-Juvénile, Centre Hospitalier de Gonesse, 2 Boulevard du 19 mars 1962, 95500, Gonesse, France
| | - Claire Desnos
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, Centre National de la Recherche Scientifique UMR 8003, 45 rue des Saints Pères, 75006, Paris, France.
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9
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Zhao T, Hao H, Wang Z, Liang Y, Feng K, He M, Yun X, Bianco PR, Sun Y, Yao B, Lei M. Multi-color structured illumination microscopy for live cell imaging based on the enhanced image recombination transform algorithm. BIOMEDICAL OPTICS EXPRESS 2021; 12:3474-3484. [PMID: 34221673 PMCID: PMC8221967 DOI: 10.1364/boe.423171] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/09/2021] [Accepted: 05/10/2021] [Indexed: 05/02/2023]
Abstract
Structured illumination microscopy (SIM) has attracted considerable interest in super-resolution, live-cell imaging because of its low light dose and high imaging speed. Obtaining a high-quality reconstruction image in SIM depends on the precise determination of the parameters of the fringe illumination pattern. The image recombination transform (IRT) algorithm is superior to other algorithms in obtaining the precise initial phase without any approximation, which is promising to provide a considerable solution to address the difficulty of initial phase estimation at low-modulation-depth conditions. However, the IRT algorithm only considers a phase shift of π∕2, which limits its applications in general scenarios. In this letter, we present a general form of IRT algorithm suitable for arbitrary phase shifts, providing a powerful tool for parameter estimation in low signal-to-noise cases. To demonstrate the effectiveness of the enhanced IRT algorithm, we constructed a multicolor, structured illumination microscope and studied at super-resolution, the cargo traffic in HRPE cells, and monitored the movement of mitochondrial structures and microtubules in COS-7 cells. The custom SIM system using the enhanced IRT algorithm allows multicolor capability and a low excitation intensity fluorescence imaging less than 1 W/cm2. High-quality super-resolution images are obtained, which demonstrates the utility of this approach in imaging in the life sciences.
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Affiliation(s)
- Tianyu Zhao
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 710119, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Authors contributed equally to this work
| | - Huiwen Hao
- State Key Laboratory of Membrane Biology & Biomedical Pioneer Innovation Center (BIOPIC) & School of Life Sciences, Peking University, Beijing 100871, China
- Authors contributed equally to this work
| | - Zhaojun Wang
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
| | - Yansheng Liang
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
| | - Kun Feng
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
| | - Minru He
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 710119, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xue Yun
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
| | - Piero R. Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Yujie Sun
- State Key Laboratory of Membrane Biology & Biomedical Pioneer Innovation Center (BIOPIC) & School of Life Sciences, Peking University, Beijing 100871, China
| | - Baoli Yao
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, Shaanxi 710119, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ming Lei
- MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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10
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Abstract
For probing small distances in living cells, methods of super-resolution microscopy and molecular sensing are reported. A main requirement is low light exposure to maintain cell viability and to avoid photobleaching of relevant fluorophores. From this point of view, Structured Illumination Microscopy (SIM), Axial Tomography, Total Internal Reflection Fluorescence Microscopy (TIRFM) and often a combination of these methods are used. To show the high potential of these techniques, measurements on cell-substrate topology as well as on intracellular translocation of the glucose transporter GLUT4 are described. In addition, molecular parameters can be deduced from spectral data, fluorescence lifetimes or non-radiative energy transfer (FRET) between a donor and an acceptor molecule. As an example, FRET between the epidermal growth factor receptor (EGFR) and the growth factor receptor-bound protein 2 (Grb2) is described. Since this interaction, as well as further processes of cellular signaling (e.g., translocation of GLUT4) are sensitive to stimulation by pharmaceutical agents, methods (e.g., TIRFM) are transferred from a fluorescence microscope to a multi-well reader system for simultaneous detection of large cell populations.
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11
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Pospíšil J, Wiebusch G, Fliegel K, Klíma M, Huser T. Highly compact and cost-effective 2-beam super-resolution structured illumination microscope based on all-fiber optic components. OPTICS EXPRESS 2021; 29:11833-11844. [PMID: 33984956 DOI: 10.1364/oe.420592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Current super-resolution structured illumination microscopes (SR-SIM) utilize relatively expensive electro-optic components and free-space optics, resulting in large setups. Moreover, high power laser sources are required to compensate for the losses associated with generating the illumination pattern by diffractive optics. Here, we present a highly compact and flexible 2D SR-SIM microscope based on all-fiber optic components (fiberSIM). Fiber-splitters deliver the laser light to the sample resulting in the interference illumination pattern. A microelectromechanical systems (MEMS) based fiber switch performs rapid pattern rotation. The pattern phase shift is achieved by the spatial displacement of one arm of the fiber interferometer using a piezoelectric crystal. Compared with existing methods, fiberSIM is highly compact and significantly reduces the SR-SIM component cost while achieving comparable results, thus providing a route to making SR-SIM technology accessible to even more laboratories in the life sciences.
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12
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Kumar V, Maity S. ER Stress-Sensor Proteins and ER-Mitochondrial Crosstalk-Signaling Beyond (ER) Stress Response. Biomolecules 2021; 11:173. [PMID: 33525374 PMCID: PMC7911976 DOI: 10.3390/biom11020173] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/14/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
Recent studies undoubtedly show the importance of inter organellar connections to maintain cellular homeostasis. In normal physiological conditions or in the presence of cellular and environmental stress, each organelle responds alone or in coordination to maintain cellular function. The Endoplasmic reticulum (ER) and mitochondria are two important organelles with very specialized structural and functional properties. These two organelles are physically connected through very specialized proteins in the region called the mitochondria-associated ER membrane (MAM). The molecular foundation of this relationship is complex and involves not only ion homeostasis through the shuttling of calcium but also many structural and apoptotic proteins. IRE1alpha and PERK are known for their canonical function as an ER stress sensor controlling unfolded protein response during ER stress. The presence of these transmembrane proteins at the MAM indicates its potential involvement in other biological functions beyond ER stress signaling. Many recent studies have now focused on the non-canonical function of these sensors. In this review, we will focus on ER mitochondrial interdependence with special emphasis on the non-canonical role of ER stress sensors beyond ER stress.
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13
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Vallese F, Catoni C, Cieri D, Barazzuol L, Ramirez O, Calore V, Bonora M, Giamogante F, Pinton P, Brini M, Calì T. An expanded palette of improved SPLICS reporters detects multiple organelle contacts in vitro and in vivo. Nat Commun 2020; 11:6069. [PMID: 33247103 PMCID: PMC7699637 DOI: 10.1038/s41467-020-19892-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 11/04/2020] [Indexed: 12/21/2022] Open
Abstract
Membrane contact sites between virtually any known organelle have been documented and, in the last decades, their study received momentum due to their importance for fundamental activities of the cell and for the subtle comprehension of many human diseases. The lack of tools to finely image inter-organelle proximity hindered our understanding on how these subcellular communication hubs mediate and regulate cell homeostasis. We develop an improved and expanded palette of split-GFP-based contact site sensors (SPLICS) for the detection of single and multiple organelle contact sites within a scalable distance range. We demonstrate their flexibility under physiological conditions and in living organisms.
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Affiliation(s)
- Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Omar Ramirez
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Valentina Calore
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Massimo Bonora
- Department of Morphology, Surgery and Experimental Medicine, Section of General Pathology, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Flavia Giamogante
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of General Pathology, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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14
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Richter V, Lanzerstorfer P, Weghuber J, Schneckenburger H. Super-Resolution Live Cell Microscopy of Membrane-Proximal Fluorophores. Int J Mol Sci 2020; 21:E7099. [PMID: 32993061 PMCID: PMC7582769 DOI: 10.3390/ijms21197099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/14/2020] [Accepted: 09/22/2020] [Indexed: 01/02/2023] Open
Abstract
Here, we present a simple and robust experimental setup for the super-resolution live cell microscopy of membrane-proximal fluorophores, which is comparably easy to perform and to implement. The method is based on Structured Illumination Microscopy (SIM) with a switchable spatial light modulator (SLM) and exchangeable objective lenses for epi-illumination and total internal reflection fluorescence (TIRF) microscopy. While, in the case of SIM (upon epi-illumination), cell layers of about 1-2 µm in close proximity to the plasma membrane can be selected by software, layers in the 100 nm range are assessed experimentally by TIRF-SIM. To show the applicability of this approach, both methods are used to measure the translocation of the glucose transporter 4 (GLUT4) from intracellular vesicles to the plasma membrane upon stimulation by insulin or insulin-mimetic compounds, with a lateral resolution of around 100 nm and an axial resolution of around 200 nm. While SIM is an appropriate method to visualize the intracellular localization of GLUT4 fused with a green fluorescent protein, TIRF-SIM permits the quantitative evaluation of its fluorescence in the plasma membrane. These imaging methods are discussed in the context of fluorescence lifetime kinetics, providing additional data for the molecular microenvironment.
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Affiliation(s)
- Verena Richter
- Institute of Applied Research, Aalen University, 373430 Aalen, Germany;
| | - Peter Lanzerstorfer
- Department of Food Technology and Nutrition, University of Applied Sciences Upper Austria, 4600 Wels, Austria; (P.L.); (J.W.)
- Austrian Competence Center for Feed and Food Quality, Safety and Innovation, 3430 Tulln, Austria
| | - Julian Weghuber
- Department of Food Technology and Nutrition, University of Applied Sciences Upper Austria, 4600 Wels, Austria; (P.L.); (J.W.)
- Austrian Competence Center for Feed and Food Quality, Safety and Innovation, 3430 Tulln, Austria
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15
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Stephens DC, Powell TW, Taraska JW, Harris DA. Imaging the rapid yet transient accumulation of regulatory lipids, lipid kinases, and protein kinases during membrane fusion, at sites of exocytosis of MMP-9 in MCF-7 cells. Lipids Health Dis 2020; 19:195. [PMID: 32829709 PMCID: PMC7444259 DOI: 10.1186/s12944-020-01374-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/17/2020] [Indexed: 11/10/2022] Open
Abstract
Background The regulation of exocytosis is physiologically vital in cells and requires a variety of distinct proteins and lipids that facilitate efficient, fast, and timely release of secretory vesicle cargo. Growing evidence suggests that regulatory lipids act as important lipid signals and regulate various biological processes including exocytosis. Though functional roles of many of these regulatory lipids has been linked to exocytosis, the dynamic behavior of these lipids during membrane fusion at sites of exocytosis in cell culture remains unknown. Methods Total internal reflection fluorescence microscopy (TIRF) was used to observe the spatial organization and temporal dynamics (i.e. spatial positioning and timing patterns) of several lipids, and accessory proteins, like lipid kinases and protein kinases, in the form of protein kinase C (PRKC) associated with sites of exocytosis of matrix metalloproteinase-9 (MMP-9) in living MCF-7 cancer cells. Results Following stimulation with phorbol myristate acetate (PMA) to promote exocytosis, a transient accumulation of several distinct regulatory lipids, lipid kinases, and protein kinases at exocytic sites was observed. This transient accumulation centered at the time of membrane fusion is followed by a rapid diffusion away from the fusion sites. Additionally, the synthesis of these regulatory lipids, degradation of these lipids, and the downstream effectors activated by these lipids, are also achieved by the recruitment and accumulation of key enzymes at exocytic sites (during the moment of cargo release). This includes key enzymes like lipid kinases, protein kinases, and phospholipases that facilitate membrane fusion and exocytosis of MMP-9. Conclusions This work suggests that these regulatory lipids and associated effector proteins are locally synthesized and/or recruited to sites of exocytosis, during membrane fusion and cargo release. More importantly, their enrichment at fusion sites serves as an important spatial and temporal organizing “element” defining individual exocytic sites.
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Affiliation(s)
- Dominique C Stephens
- Department of Chemistry, Howard University, 525 College Street NW, Washington, D.C, 20059, USA
| | - Tyrel W Powell
- Department of Chemistry, Howard University, 525 College Street NW, Washington, D.C, 20059, USA
| | - Justin W Taraska
- Laboratory of Molecular Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Dinari A Harris
- Department of Chemistry, Howard University, 525 College Street NW, Washington, D.C, 20059, USA.
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16
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Roth J, Mehl J, Rohrbach A. Fast TIRF-SIM imaging of dynamic, low-fluorescent biological samples. BIOMEDICAL OPTICS EXPRESS 2020; 11:4008-4026. [PMID: 33014582 PMCID: PMC7510889 DOI: 10.1364/boe.391561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 05/26/2023]
Abstract
Fluorescence microscopy is the standard imaging technique to investigate the structures and dynamics of living cells. However, increasing the spatial resolution comes at the cost of temporal resolution and vice versa. In addition, the number of images that can be taken in sufficiently high quality is limited by fluorescence bleaching. Hence, super-resolved imaging at several Hertz of low fluorescent biological samples is still a big challenge and, especially in structured illumination microscopy (SIM), is often visible as imaging artifacts. In this paper, we present a TIRF-SIM system based on scan-mirrors and a Michelson interferometer, which generates images at 110 nm spatial resolution and up to 8 Hz temporal resolution. High resolution becomes possible by optimizing the illumination interference contrast, even for low fluorescent, moving samples. We provide a framework and guidelines on how the modulation contrast, which depends on laser coherence, polarization, beam displacement or sample movements, can be mapped over the entire field of view. In addition, we characterize the influence of the signal-to-noise ratio and the Wiener filtering on the quality of reconstructed SIM images, both in real and frequency space. Our results are supported by theoretical descriptions containing the parameters leading to image artifacts. This study aims to help microscopists to better understand and adjust optical parameters for structured illumination, thereby leading to more trustworthy measurements and analyses of biological dynamics.
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Affiliation(s)
- Julian Roth
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Germany
| | - Johanna Mehl
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Germany
- Laboratory of Applied Mechanobiology, Department of Health Science and Technology, ETH Zürich, Switzerland
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering, University of Freiburg, Germany
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17
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Oheim M, Salomon A, Brunstein M. Supercritical Angle Fluorescence Microscopy and Spectroscopy. Biophys J 2020; 118:2339-2348. [PMID: 32348720 PMCID: PMC7231923 DOI: 10.1016/j.bpj.2020.03.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/13/2020] [Accepted: 03/23/2020] [Indexed: 01/06/2023] Open
Abstract
Fluorescence detection, either involving propagating or near-field emission, is widely being used in spectroscopy, sensing, and microscopy. Total internal reflection fluorescence (TIRF) confines fluorescence excitation by an evanescent (near) field, and it is a popular contrast generator for surface-selective fluorescence assays. Its emission equivalent, supercritical angle fluorescence (SAF), is comparably less established, although it achieves a similar optical sectioning as TIRF does. SAF emerges when a fluorescing molecule is located very close to an interface and its near-field emission couples to the higher refractive index medium (n2 >n1) and becomes propagative. Then, most fluorescence is detectable on the side of the higher-index substrate, and a large fraction of this fluorescence is emitted into angles forbidden by Snell's law. SAF, as well as the undercritical angle fluorescence (UAF; far-field emission) components, can be collected with microscope objectives having a high-enough detection aperture (numerical aperture >n2) and be separated in the back focal plane by Fourier filtering. The back focal plane image encodes information about the fluorophore radiation pattern, and it can be analyzed to yield precise information about the refractive index in which the emitters are embedded, their nanometric distance from the interface, and their orientation. A SAF microscope can retrieve this near-field information through wide-field optics in a spatially resolved manner, and this functionality can be added to an existing inverted microscope. Here, we describe the potential underpinning of SAF microscopy and spectroscopy, particularly in comparison with TIRF. We review the challenges and opportunities that SAF presents from a biophysical perspective, and we discuss areas in which we see potential.
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Affiliation(s)
- Martin Oheim
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, CNRS, Paris, France.
| | - Adi Salomon
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, CNRS, Paris, France; Department of Chemistry, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Maia Brunstein
- Saints-Pères Paris Institute for the Neurosciences, Université de Paris, CNRS, Paris, France; Chaire d'Excellence Junior, Université Sorbonne Paris Cité, Paris, France
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18
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Schaefer M, Kalwa H. Theoretical background of light-emitting diode total internal reflection fluorescence microscopy and photobleaching lifetime analysis of membrane-associated proteins-Part II. JOURNAL OF BIOPHOTONICS 2020; 13:e201960181. [PMID: 31965728 DOI: 10.1002/jbio.201960181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/16/2019] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
The selective microscopic imaging of the plasma membrane and adjacent structures by total internal reflection fluorescence (TIRF) microscopy is a versatile and frequently used technique in cell biology. A reduction of imaging artifacts in objective-type TIRF microscopy can be achieved by circular or multi-spot laser illumination or by using noncoherent light sources that are projected into the back focal plane as a light annulus. Light-emitting diode (LED)-based TIRF excitation is a recent advancement of the latter strategy. While some basic principles of LED-TIRF remain the same as in laser-based methods, the calculation of penetration depth, the flatness of illumination and the amount of available illumination power differ. This study provides the theoretical framework for the construction and adjustment of LED-TIRF. Using state-of-the art high power LED emitters, LED-TIRF achieves excitation efficiencies that are comparable to laser-based systems and homogenously illuminate the entire field of view, thus, allowing variation of the penetration depth or quantitative photobleaching-assisted imaging protocols. Using autofluorescent transmembrane, soluble and membrane-attached fusion proteins, we provide examples for a photobleaching-based assessment of the exchange kinetics of proteins within living human endothelial cells.
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Affiliation(s)
- Michael Schaefer
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Hermann Kalwa
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
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19
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ZENG HUI, YANG HUAIDONG, LIU GUOXUAN, ZHANG SICHUN, ZHANG XINRONG, ZHANG YINXIN. Simultaneous multicolour imaging using quantum dot structured illumination microscopy. J Microsc 2020; 277:32-41. [DOI: 10.1111/jmi.12862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 01/09/2020] [Indexed: 02/06/2023]
Affiliation(s)
- HUI ZENG
- State Key Laboratory of Precision Measurement Technology and InstrumentsTsinghua UniversityBeijing China
| | - HUAIDONG YANG
- State Key Laboratory of Precision Measurement Technology and InstrumentsTsinghua UniversityBeijing China
| | - GUOXUAN LIU
- State Key Laboratory of Precision Measurement Technology and InstrumentsTsinghua UniversityBeijing China
| | - SICHUN ZHANG
- Beijing Key Laboratory of Microanalytical Methods and Instruments, Department of ChemistryTsinghua UniversityBeijing China
| | - XINRONG ZHANG
- Beijing Key Laboratory of Microanalytical Methods and Instruments, Department of ChemistryTsinghua UniversityBeijing China
| | - YINXIN ZHANG
- Key Laboratory of Opto‐electronic Information Technology, Ministry of EducationTianJin UniversityTianjin China
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20
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Vallese F, Barazzuol L, Maso L, Brini M, Calì T. ER-Mitochondria Calcium Transfer, Organelle Contacts and Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:719-746. [PMID: 31646532 DOI: 10.1007/978-3-030-12457-1_29] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is generally accepted that interorganellar contacts are central to the control of cellular physiology. Virtually, any intracellular organelle can come into proximity with each other and, by establishing physical protein-mediated contacts within a selected fraction of the membrane surface, novel specific functions are acquired. Endoplasmic reticulum (ER) contacts with mitochondria are among the best studied and have a major role in Ca2+ and lipid transfer, signaling, and membrane dynamics.Their functional (and structural) diversity, their dynamic nature as well as the growing number of new players involved in the tethering concurred to make their monitoring difficult especially in living cells. This review focuses on the most established examples of tethers/modulators of the ER-mitochondria interface and on the roles of these contacts in health and disease by specifically dissecting how Ca2+ transfer occurs and how mishandling eventually leads to disease. Additional functions of the ER-mitochondria interface and an overview of the currently available methods to measure/quantify the ER-mitochondria interface will also be discussed.
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Affiliation(s)
- Francesca Vallese
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lorenzo Maso
- Department of Biology, University of Padua, Padua, Italy
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Padua Neuroscience Center (PNC), Padua, Italy.
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21
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Kogel A, Kalwa H, Urban N, Schaefer M. Artifact-free objective-type multicolor total internal reflection fluorescence microscopy with light-emitting diode light sources-Part I. JOURNAL OF BIOPHOTONICS 2019; 12:e201900033. [PMID: 31148410 DOI: 10.1002/jbio.201900033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/07/2019] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Total internal reflection fluorescence excitation (TIRF) microscopy allows the selective observation of fluorescent molecules in immediate proximity to an interface between different refractive indices. Objective-type or prism-less TIRF excitation is typically achieved with laser light sources. We here propose a simple, yet optically advantageous light-emitting diode (LED)-based implementation of objective-type TIRF (LED-TIRF). The proposed LED-TIRF condenser is affordable and easy to set up at any epifluorescence microscope to perform multicolor TIRF and/or combined TIRF-epifluorescence imaging with even illumination of the entire field of view. Electrical control of LED light sources replaces mechanical shutters or optical modulators. LED-TIRF microscopy eliminates safety burdens that are associated with laser sources, offers favorable instrument lifetime and stability without active cooling. The non-coherent light source and the type of projection eliminate interference fringing and local scattering artifacts that are associated with conventional laser-TIRF. Unlike azimuthal spinning laser-TIRF, LED-TIRF does not require synchronization between beam rotation and the camera and can be monitored with either global or rolling shutter cameras. Typical implementations, such as live cell multicolor imaging in TIRF and epifluorescence of imaging of short-lived, localized translocation events of a Ca2+ -sensitive protein kinase C α fusion protein are demonstrated.
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Affiliation(s)
- Alexander Kogel
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Hermann Kalwa
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Nicole Urban
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Michael Schaefer
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
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22
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Denizot A, Arizono M, Nägerl UV, Soula H, Berry H. Simulation of calcium signaling in fine astrocytic processes: Effect of spatial properties on spontaneous activity. PLoS Comput Biol 2019; 15:e1006795. [PMID: 31425510 PMCID: PMC6726244 DOI: 10.1371/journal.pcbi.1006795] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/04/2019] [Accepted: 07/08/2019] [Indexed: 12/20/2022] Open
Abstract
Astrocytes, a glial cell type of the central nervous system, have emerged as detectors and regulators of neuronal information processing. Astrocyte excitability resides in transient variations of free cytosolic calcium concentration over a range of temporal and spatial scales, from sub-microdomains to waves propagating throughout the cell. Despite extensive experimental approaches, it is not clear how these signals are transmitted to and integrated within an astrocyte. The localization of the main molecular actors and the geometry of the system, including the spatial organization of calcium channels IP3R, are deemed essential. However, as most calcium signals occur in astrocytic ramifications that are too fine to be resolved by conventional light microscopy, most of those spatial data are unknown and computational modeling remains the only methodology to study this issue. Here, we propose an IP3R-mediated calcium signaling model for dynamics in such small sub-cellular volumes. To account for the expected stochasticity and low copy numbers, our model is both spatially explicit and particle-based. Extensive simulations show that spontaneous calcium signals arise in the model via the interplay between excitability and stochasticity. The model reproduces the main forms of calcium signals and indicates that their frequency crucially depends on the spatial organization of the IP3R channels. Importantly, we show that two processes expressing exactly the same calcium channels can display different types of calcium signals depending on the spatial organization of the channels. Our model with realistic process volume and calcium concentrations successfully reproduces spontaneous calcium signals that we measured in calcium micro-domains with confocal microscopy and predicts that local variations of calcium indicators might contribute to the diversity of calcium signals observed in astrocytes. To our knowledge, this model is the first model suited to investigate calcium dynamics in fine astrocytic processes and to propose plausible mechanisms responsible for their variability.
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Affiliation(s)
- Audrey Denizot
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Hédi Soula
- INRIA, F-69603, Villeurbanne, France
- Univ P&M Curie, CRC, INSERM UMRS 1138, F-75006, Paris, France
| | - Hugues Berry
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
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23
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Brunstein M, Salomon A, Oheim M. Decoding the Information Contained in Fluorophore Radiation Patterns. ACS NANO 2018; 12:11725-11730. [PMID: 30995713 DOI: 10.1021/acsnano.8b08696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dipole radiation patterns change when a fluorescent molecule comes close to the boundary between media of different refractive indices. Near-interface molecules emit mostly into the higher-index medium, predominantly around the critical angle. The radiation pattern encodes information about the emitter distance, orientation, and the refractive index of the embedding medium. Analyses of the supercritical angle fluorescence on pupil plane images can retrieve this information and have been applied both for refractometry with subcellular resolution and for the detection of metabolically active cancerous cells. In this issue of ACS Nano, Ferdman et al. employ this strategy in a label-free assay for detecting single bacteria, based on measuring the refractive-index change produced by bacterial growth in a fluorophore-coated microfluidic channel.
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Affiliation(s)
- Maia Brunstein
- CNRS, UMR 8118, Brain Physiology Laboratory , 45 rue des Saints Pères , Paris F-75006 France
- Fédération de Recherche en Neurosciences FR3636, Faculté de Sciences Fondamentales et Biomédicales , Université Paris Descartes , PRES Sorbonne Paris Cité , Paris F-75006 , France
- Chaire d'excellence Université Sorbonne Paris Cité , Paris F-75006 France
| | - Adi Salomon
- Department of Chemistry , Institute of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University , Ramat-Gan 5290002 , Israel
| | - Martin Oheim
- CNRS, UMR 8118, Brain Physiology Laboratory , 45 rue des Saints Pères , Paris F-75006 France
- Fédération de Recherche en Neurosciences FR3636, Faculté de Sciences Fondamentales et Biomédicales , Université Paris Descartes , PRES Sorbonne Paris Cité , Paris F-75006 , France
- Chaire d'excellence Université Sorbonne Paris Cité , Paris F-75006 France
- Joseph Meyerhof Invited Professor, Department of Biomolecular Sciences , Weizmann Institute for Science , Rehovot 7610001 , Israel
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24
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Wu Y, Shroff H. Faster, sharper, and deeper: structured illumination microscopy for biological imaging. Nat Methods 2018; 15:1011-1019. [PMID: 30478322 DOI: 10.1038/s41592-018-0211-z] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 10/02/2018] [Indexed: 11/09/2022]
Abstract
Structured illumination microscopy (SIM) allows rapid, super-resolution (SR) imaging in live specimens. We review recent technical advances in SR-SIM, with emphasis on imaging speed, resolution, and depth. Since its introduction decades ago, the technique has grown to offer myriad implementations, each with its own strengths and weaknesses. We discuss these, aiming to provide a practical guide for biologists and to highlight which approach is best suited to a given application.
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Affiliation(s)
- Yicong Wu
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA.
| | - Hari Shroff
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
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25
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Chen Y, Cao R, Liu W, Zhu D, Zhang Z, Kuang C, Liu X. Widefield and total internal reflection fluorescent structured illumination microscopy with scanning galvo mirrors. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-9. [PMID: 29693956 DOI: 10.1117/1.jbo.23.4.046007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/03/2018] [Indexed: 05/15/2023]
Abstract
We present an alternative approach to realize structured illumination microscopy (SIM), which is capable for live cell imaging. The prototype utilizes two sets of scanning galvo mirrors, a polarization converter and a piezo-platform to generate a fast shifted, s-polarization interfered and periodic variable illumination patterns. By changing the angle of the scanning galvanometer, we can change the position of the spots at the pupil plane of the objective lens arbitrarily, making it easy to switch between widefield and total internal reflection fluorescent-SIM mode and adapting the penetration depth in the sample. Also, a twofold resolution improvement is achieved in our experiments. The prototype offers more flexibility of pattern period and illumination orientation changing than previous systems.
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Affiliation(s)
- Youhua Chen
- Zhejiang Univ., China
- North Univ. of China, China
| | | | | | | | | | | | - Xu Liu
- Zhejiang Univ., China
- Shanxi Univ., China
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26
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Csordás G, Weaver D, Hajnóczky G. Endoplasmic Reticulum-Mitochondrial Contactology: Structure and Signaling Functions. Trends Cell Biol 2018; 28:523-540. [PMID: 29588129 DOI: 10.1016/j.tcb.2018.02.009] [Citation(s) in RCA: 351] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 02/08/2023]
Abstract
Interorganellar contacts are increasingly recognized as central to the control of cellular behavior. These contacts, which typically involve a small fraction of the endomembrane surface, are local communication hubs that resemble synapses. We propose the term contactology to denote the analysis of interorganellar contacts. Endoplasmic reticulum (ER) contacts with mitochondria were recognized several decades ago; major roles in ion and lipid transfer, signaling, and membrane dynamics have been established, while others continue to emerge. The functional diversity of ER-mitochondrial (ER-mito) contacts is mirrored in their structural heterogeneity, with subspecialization likely supported by multiple, different linker-forming protein structures. The nanoscale size of the contacts has made studying their structure, function, and dynamics difficult. This review focuses on the structure of the ER-mito contacts, methods for studying them, and the roles of contacts in Ca2+ and reactive oxygen species (ROS) signaling.
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Affiliation(s)
- György Csordás
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - David Weaver
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - György Hajnóczky
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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27
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Tehrani KF, Pendleton EG, Southern WM, Call JA, Mortensen LJ. Two-photon deep-tissue spatially resolved mitochondrial imaging using membrane potential fluorescence fluctuations. BIOMEDICAL OPTICS EXPRESS 2018; 9:254-259. [PMID: 29359101 PMCID: PMC5772580 DOI: 10.1364/boe.9.000254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/04/2017] [Accepted: 12/13/2017] [Indexed: 05/04/2023]
Abstract
Cell metabolism and viability are directly reflected in their mitochondria. Imaging-based analysis of mitochondrial morphological structure, size and dynamic characteristics can therefore provide critical insight into cell function. However, mitochondria are often very abundant, and due to their close to diffraction-limit size, it is often non-trivial to distinguish a tubular or large mitochondrion from an ensemble of punctate mitochondria. In this paper, we use membrane potential dependent fluorescence fluctuations of individual mitochondria to resolve them using an approach similar to single molecule localization microscopy. We use 2-photon microscopy to image mitochondrial intensity fluctuations at 200 μm deep inside an intact in-vivo mouse soleus muscle. By analyzing the acquired images, we can reconstruct images with an extra layer of information about individual mitochondria, separated from their ensemble. Our analysis shows a factor of 14 improvement in detection of mitochondria.
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Affiliation(s)
- Kayvan Forouhesh Tehrani
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
| | - Emily G. Pendleton
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
| | | | - Jarrod A. Call
- Department of Kinesiology, University of Georgia, Athens, GA 30602, USA
| | - Luke J. Mortensen
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA 30602, USA
- School of Materials, Chemical, and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA
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28
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Heller JP, Rusakov DA. The Nanoworld of the Tripartite Synapse: Insights from Super-Resolution Microscopy. Front Cell Neurosci 2017; 11:374. [PMID: 29225567 PMCID: PMC5705901 DOI: 10.3389/fncel.2017.00374] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/10/2017] [Indexed: 12/17/2022] Open
Abstract
Synaptic connections between individual nerve cells are fundamental to the process of information transfer and storage in the brain. Over the past decades a third key partner of the synaptic machinery has been unveiled: ultrathin processes of electrically passive astroglia which often surround pre- and postsynaptic structures. The recent advent of super-resolution (SR) microscopy has begun to uncover the dynamic nanoworld of synapses and their astroglial environment. Here we overview and discuss the current progress in our understanding of the synaptic nanoenvironment, as gleaned from the imaging methods that go beyond the diffraction limit of conventional light microscopy. We argue that such methods are essential to achieve a new level of comprehension pertinent to the principles of signal integration in the brain.
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Affiliation(s)
- Janosch P Heller
- UCL Institute of Neurology, University College London, London, United Kingdom
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, United Kingdom.,Institute of Neuroscience, University of Nizhny Novgorod, Nizhny Novgorod, Russia
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29
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Erpapazoglou Z, Mouton-Liger F, Corti O. From dysfunctional endoplasmic reticulum-mitochondria coupling to neurodegeneration. Neurochem Int 2017; 109:171-183. [DOI: 10.1016/j.neuint.2017.03.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 03/27/2017] [Accepted: 03/30/2017] [Indexed: 12/22/2022]
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30
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Ong SB, Kalkhoran SB, Hernández-Reséndiz S, Samangouei P, Ong SG, Hausenloy DJ. Mitochondrial-Shaping Proteins in Cardiac Health and Disease - the Long and the Short of It! Cardiovasc Drugs Ther 2017; 31:87-107. [PMID: 28190190 PMCID: PMC5346600 DOI: 10.1007/s10557-016-6710-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mitochondrial health is critically dependent on the ability of mitochondria to undergo changes in mitochondrial morphology, a process which is regulated by mitochondrial shaping proteins. Mitochondria undergo fission to generate fragmented discrete organelles, a process which is mediated by the mitochondrial fission proteins (Drp1, hFIS1, Mff and MiD49/51), and is required for cell division, and to remove damaged mitochondria by mitophagy. Mitochondria undergo fusion to form elongated interconnected networks, a process which is orchestrated by the mitochondrial fusion proteins (Mfn1, Mfn2 and OPA1), and which enables the replenishment of damaged mitochondrial DNA. In the adult heart, mitochondria are relatively static, are constrained in their movement, and are characteristically arranged into 3 distinct subpopulations based on their locality and function (subsarcolemmal, myofibrillar, and perinuclear). Although the mitochondria are arranged differently, emerging data supports a role for the mitochondrial shaping proteins in cardiac health and disease. Interestingly, in the adult heart, it appears that the pleiotropic effects of the mitochondrial fusion proteins, Mfn2 (endoplasmic reticulum-tethering, mitophagy) and OPA1 (cristae remodeling, regulation of apoptosis, and energy production) may play more important roles than their pro-fusion effects. In this review article, we provide an overview of the mitochondrial fusion and fission proteins in the adult heart, and highlight their roles as novel therapeutic targets for treating cardiac disease.
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Affiliation(s)
- Sang-Bing Ong
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Siavash Beikoghli Kalkhoran
- The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK
| | - Sauri Hernández-Reséndiz
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Parisa Samangouei
- The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK
| | - Sang-Ging Ong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Derek John Hausenloy
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore. .,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore. .,The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK. .,The National Institute of Health Research, University College London Hospitals Biomedical Research Centre, London, UK.
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31
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Lovelace MD, Powter EE, Coleman PR, Zhao Y, Parker A, Chang GH, Lay AJ, Hunter J, McGrath AP, Jormakka M, Bertolino P, McCaughan G, Kavallaris M, Vadas MA, Gamble JR. The RhoGAP protein ARHGAP18/SENEX localizes to microtubules and regulates their stability in endothelial cells. Mol Biol Cell 2017; 28:1066-1078. [PMID: 28251925 PMCID: PMC5391183 DOI: 10.1091/mbc.e16-05-0285] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 02/10/2017] [Accepted: 02/17/2017] [Indexed: 11/17/2022] Open
Abstract
Localization of a regulator of RhoGTPases (ARHGAP18) is important for microtubule stability and endothelial cell function. The localization is demonstrated by advanced imaging and biochemical techniques. RhoGTPases are important regulators of the cell cytoskeleton, controlling cell shape, migration and proliferation. Previously we showed that ARHGAP18 in endothelial cells is important in cell junctions. Here we show, using structured illumination microscopy (SIM), ground-state depletion (GSD), and total internal reflection fluorescence microscopy (TIRF) that a proportion of ARHGAP18 localizes to microtubules in endothelial cells, as well as in nonendothelial cells, an association confirmed biochemically. In endothelial cells, some ARHGAP18 puncta also colocalized to Weibel–Palade bodies on the microtubules. Depletion of ARHGAP18 by small interfering RNA or analysis of endothelial cells isolated from ARHGAP18-knockout mice showed microtubule destabilization, as evidenced by altered morphology and decreased acetylated α-tubulin and glu-tubulin. The destabilization was rescued by inhibition of ROCK and histone deacetylase 6 but not by a GAP-mutant form of ARHGAP18. Depletion of ARHGAP18 resulted in a failure to secrete endothelin-1 and a reduction in neutrophil transmigration, both known to be microtubule dependent. Thrombin, a critical regulator of the Rho-mediated barrier function of endothelial cells through microtubule destabilization, enhanced the plasma membrane–bound fraction of ARHGAP18. Thus, in endothelial cells, ARHGAP18 may act as a significant regulator of vascular homeostasis.
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Affiliation(s)
- Michael D Lovelace
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Elizabeth E Powter
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Paul R Coleman
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Yang Zhao
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Amelia Parker
- Tumour Biology and Targeting Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Garry H Chang
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Angelina J Lay
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Julie Hunter
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Aaron P McGrath
- Structural Biology Laboratory, University of Sydney, Sydney, NSW 2050, Australia
| | - Mika Jormakka
- Structural Biology Laboratory, University of Sydney, Sydney, NSW 2050, Australia
| | - Patrick Bertolino
- Liver Immunology Laboratory, University of Sydney, Sydney, NSW 2050, Australia
| | - Geoffrey McCaughan
- Liver Biology and Cancer Laboratory, Centenary Institute, University of Sydney, Sydney, NSW 2050, Australia
| | - Maria Kavallaris
- Tumour Biology and Targeting Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2052, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and Australian Centre for NanoMedicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mathew A Vadas
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
| | - Jennifer R Gamble
- Centre for the Endothelium, Vascular Biology Program, University of Sydney, Sydney, NSW 2050, Australia
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32
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Fiolka R. Clearer view for TIRF and oblique illumination microscopy. OPTICS EXPRESS 2016; 24:29556-29567. [PMID: 28059342 DOI: 10.1364/oe.24.029556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In Total Internal Reflection Fluorescence (TIRF) microscopy, the sample is illuminated with an evanescent field that yields a thin optical section. However, its widefield detection has no rejection mechanism against out-of-focus blur from scattered light that can compromise TIRF images. Here I demonstrate that via structured illumination, out-of-focus blur can be effectively suppressed in TIRF microscopy, yielding strikingly clearer images. The same mechanism can also be applied to oblique illumination schemes that extend the reach of TIRF microscopy beyond the basal surface of the cell. The two imaging modes are used to image a biosensor, clathrin coated vesicles and the actin cytoskeleton in different cell types with improved contrast.
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33
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Brunstein M, Oheim M. Dependence of descriptors of co-localization on microscope spatiotemporal resolution and the choice of regions of interest. Microsc Res Tech 2016; 80:220-230. [DOI: 10.1002/jemt.22790] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Maia Brunstein
- CNRS UMR 8118; Brain Physiology Laboratory; Paris F-75006 France
- Fédération de Recherche en Neurosciences FR 3636, Faculté de Sciences Fondamentales et Biomédicales; Université Paris Descartes; PRES Sorbonne Paris Cité Paris F-75006 France
- Chaire d'excellence, IDEX; Université Sorbonne Paris Cité; Paris F-75006 France
| | - Martin Oheim
- CNRS UMR 8118; Brain Physiology Laboratory; Paris F-75006 France
- Fédération de Recherche en Neurosciences FR 3636, Faculté de Sciences Fondamentales et Biomédicales; Université Paris Descartes; PRES Sorbonne Paris Cité Paris F-75006 France
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34
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Young LJ, Ströhl F, Kaminski CF. A Guide to Structured Illumination TIRF Microscopy at High Speed with Multiple Colors. J Vis Exp 2016. [PMID: 27285848 PMCID: PMC4927749 DOI: 10.3791/53988] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Optical super-resolution imaging with structured illumination microscopy (SIM) is a key technology for the visualization of processes at the molecular level in the chemical and biomedical sciences. Although commercial SIM systems are available, systems that are custom designed in the laboratory can outperform commercial systems, the latter typically designed for ease of use and general purpose applications, both in terms of imaging fidelity and speed. This article presents an in-depth guide to building a SIM system that uses total internal reflection (TIR) illumination and is capable of imaging at up to 10 Hz in three colors at a resolution reaching 100 nm. Due to the combination of SIM and TIRF, the system provides better image contrast than rival technologies. To achieve these specifications, several optical elements are used to enable automated control over the polarization state and spatial structure of the illumination light for all available excitation wavelengths. Full details on hardware implementation and control are given to achieve synchronization between excitation light pattern generation, wavelength, polarization state, and camera control with an emphasis on achieving maximum acquisition frame rate. A step-by-step protocol for system alignment and calibration is presented and the achievable resolution improvement is validated on ideal test samples. The capability for video-rate super-resolution imaging is demonstrated with living cells.
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Affiliation(s)
- Laurence J Young
- Department of Chemical Engineering and Biotechnology, University of Cambridge;
| | - Florian Ströhl
- Department of Chemical Engineering and Biotechnology, University of Cambridge
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge
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35
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Abstract
Soft fluorescent nanomaterials have attracted recent attention as imaging agents for biological applications, because they provide the advantages of good biocompatibility, high brightness, and easy biofunctionalization. Here, we provide a survey of recent developments in fluorescent soft nano-sized biological imaging agents. Various soft fluorescent nanoparticles (NPs) (including dye-doped polymer NPs, semiconducting polymer NPs, small-molecule organic NPs, nanogels, micelles, vesicles, and biomaterial-based NPs) are summarized from the perspectives of preparation methods, structure, optical properties, and surface functionalization. Based on both optical and functional properties of the nano-sized imaging agents, their applications are then reviewed in terms of in vitro imaging, in vivo imaging, and cellular-process imaging, by means of specific or nonspecific targeting.
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Affiliation(s)
- Hong-Shang Peng
- Department of Chemistry, University of Washington, Seattle, WA, USA.
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36
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Curthoys NM, Parent M, Mlodzianoski M, Nelson AJ, Lilieholm J, Butler MB, Valles M, Hess ST. Dances with Membranes: Breakthroughs from Super-resolution Imaging. CURRENT TOPICS IN MEMBRANES 2015; 75:59-123. [PMID: 26015281 PMCID: PMC5584789 DOI: 10.1016/bs.ctm.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Biological membrane organization mediates numerous cellular functions and has also been connected with an immense number of human diseases. However, until recently, experimental methodologies have been unable to directly visualize the nanoscale details of biological membranes, particularly in intact living cells. Numerous models explaining membrane organization have been proposed, but testing those models has required indirect methods; the desire to directly image proteins and lipids in living cell membranes is a strong motivation for the advancement of technology. The development of super-resolution microscopy has provided powerful tools for quantification of membrane organization at the level of individual proteins and lipids, and many of these tools are compatible with living cells. Previously inaccessible questions are now being addressed, and the field of membrane biology is developing rapidly. This chapter discusses how the development of super-resolution microscopy has led to fundamental advances in the field of biological membrane organization. We summarize the history and some models explaining how proteins are organized in cell membranes, and give an overview of various super-resolution techniques and methods of quantifying super-resolution data. We discuss the application of super-resolution techniques to membrane biology in general, and also with specific reference to the fields of actin and actin-binding proteins, virus infection, mitochondria, immune cell biology, and phosphoinositide signaling. Finally, we present our hopes and expectations for the future of super-resolution microscopy in the field of membrane biology.
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Affiliation(s)
- Nikki M. Curthoys
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Parent
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | | | - Andrew J. Nelson
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Jennifer Lilieholm
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Michael B. Butler
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Valles
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Samuel T. Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
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37
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Lu-Walther HW, Kielhorn M, Förster R, Jost A, Wicker K, Heintzmann R. fastSIM: a practical implementation of fast structured illumination microscopy. Methods Appl Fluoresc 2015; 3:014001. [DOI: 10.1088/2050-6120/3/1/014001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Devauges V, Matthews DR, Aluko J, Nedbal J, Levitt JA, Poland SP, Coban O, Weitsman G, Monypenny J, Ng T, Ameer-Beg SM. Steady-state acceptor fluorescence anisotropy imaging under evanescent excitation for visualisation of FRET at the plasma membrane. PLoS One 2014; 9:e110695. [PMID: 25360776 PMCID: PMC4215982 DOI: 10.1371/journal.pone.0110695] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/15/2014] [Indexed: 11/22/2022] Open
Abstract
We present a novel imaging system combining total internal reflection fluorescence (TIRF) microscopy with measurement of steady-state acceptor fluorescence anisotropy in order to perform live cell Förster Resonance Energy Transfer (FRET) imaging at the plasma membrane. We compare directly the imaging performance of fluorescence anisotropy resolved TIRF with epifluorescence illumination. The use of high numerical aperture objective for TIRF required correction for induced depolarization factors. This arrangement enabled visualisation of conformational changes of a Raichu-Cdc42 FRET biosensor by measurement of intramolecular FRET between eGFP and mRFP1. Higher activity of the probe was found at the cell plasma membrane compared to intracellularly. Imaging fluorescence anisotropy in TIRF allowed clear differentiation of the Raichu-Cdc42 biosensor from negative control mutants. Finally, inhibition of Cdc42 was imaged dynamically in live cells, where we show temporal changes of the activity of the Raichu-Cdc42 biosensor.
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Affiliation(s)
- Viviane Devauges
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Daniel R. Matthews
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Justin Aluko
- Department of Physics, King's College London, London, United Kingdom
| | - Jakub Nedbal
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - James A. Levitt
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Simon P. Poland
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Oana Coban
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Gregory Weitsman
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - James Monypenny
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Tony Ng
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
- UCL Cancer Institute, University College London, London, United Kingdom
| | - Simon M. Ameer-Beg
- Richard Dimbleby Cancer Research Laboratory, Division of Cancer Studies and Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
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Brunstein M, Hérault K, Oheim M. Eliminating unwanted far-field excitation in objective-type TIRF. Part II. combined evanescent-wave excitation and supercritical-angle fluorescence detection improves optical sectioning. Biophys J 2014; 106:1044-56. [PMID: 24606929 PMCID: PMC4026779 DOI: 10.1016/j.bpj.2013.12.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 12/29/2022] Open
Abstract
Azimuthal beam scanning makes evanescent-wave (EW) excitation isotropic, thereby producing total internal reflection fluorescence (TIRF) images that are evenly lit. However, beam spinning does not fundamentally address the problem of propagating excitation light that is contaminating objective-type TIRF. Far-field excitation depends more on the specific objective than on cell scattering. As a consequence, the excitation impurities in objective-type TIRF are only weakly affected by changes of azimuthal or polar beam angle. These are the main results of the first part of this study (Eliminating unwanted far-field excitation in objective-type TIRF. Pt.1. Identifying sources of nonevanescent excitation light). This second part focuses on exactly where up beam in the illumination system stray light is generated that gives rise to nonevanescent components in TIRF. Using dark-field imaging of scattered excitation light we pinpoint the objective, intermediate lenses and, particularly, the beam scanner as the major sources of stray excitation. We study how adhesion-molecule coating and astrocytes or BON cells grown on the coverslip surface modify the dark-field signal. On flat and weakly scattering cells, most background comes from stray reflections produced far from the sample plane, in the beam scanner and the objective lens. On thick, optically dense cells roughly half of the scatter is generated by the sample itself. We finally show that combining objective-type EW excitation with supercritical-angle fluorescence (SAF) detection efficiently rejects the fluorescence originating from deeper sample regions. We demonstrate that SAF improves the surface selectivity of TIRF, even at shallow penetration depths. The coplanar microscopy scheme presented here merges the benefits of beam spinning EW excitation and SAF detection and provides the conditions for quantitative wide-field imaging of fluorophore dynamics at or near the plasma membrane.
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Affiliation(s)
- Maia Brunstein
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France
| | - Karine Hérault
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France
| | - Martin Oheim
- CNRS, UMR 8154, Paris, F-75006 France; INSERM, U603, Paris, F-75006 France; Laboratoire de Neurophysiologie et Nouvelles Microscopies, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris, F-75006 France.
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40
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Notelaers K, Rocha S, Paesen R, Swinnen N, Vangindertael J, Meier JC, Rigo JM, Ameloot M, Hofkens J. Membrane distribution of the glycine receptor α3 studied by optical super-resolution microscopy. Histochem Cell Biol 2014; 142:79-90. [PMID: 24553792 DOI: 10.1007/s00418-014-1197-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2014] [Indexed: 11/24/2022]
Abstract
In this study, the effect of glycine receptor (GlyR) α3 alternative RNA splicing on the distribution of receptors in the membrane of human embryonic kidney 293 cells is investigated using optical super-resolution microscopy. Direct stochastic optical reconstruction microscopy is used to image both α3K and α3L splice variants individually and together using single- and dual-color imaging. Pair correlation analysis is used to extract quantitative measures from the resulting images. Autocorrelation analysis of the individually expressed variants reveals clustering of both variants, yet with differing properties. The cluster size is increased for α3L compared to α3K (mean radius 92 ± 4 and 56 ± 3 nm, respectively), yet an even bigger difference is found in the cluster density (9,870 ± 1,433 and 1,747 ± 200 μm(-2), respectively). Furthermore, cross-correlation analysis revealed that upon co-expression, clusters colocalize on the same spatial scales as for individually expressed receptors (mean co-cluster radius 94 ± 6 nm). These results demonstrate that RNA splicing determines GlyR α3 membrane distribution, which has consequences for neuronal GlyR physiology and function.
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Affiliation(s)
- Kristof Notelaers
- Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
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