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Barbotin A, Billaudeau C, Sezgin E, Carballido-López R. Quantification of membrane fluidity in bacteria using TIR-FCS. Biophys J 2024:S0006-3495(24)00407-7. [PMID: 38877702 DOI: 10.1016/j.bpj.2024.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 05/28/2024] [Accepted: 06/10/2024] [Indexed: 06/16/2024] Open
Abstract
Plasma membrane fluidity is an important phenotypic feature that regulates the diffusion, function, and folding of transmembrane and membrane-associated proteins. In bacterial cells, variations in membrane fluidity are known to affect respiration, transport, and antibiotic resistance. Membrane fluidity must therefore be tightly regulated to adapt to environmental variations and stresses such as temperature fluctuations or osmotic shocks. Quantitative investigation of bacterial membrane fluidity has been, however, limited due to the lack of available tools, primarily due to the small size and membrane curvature of bacteria that preclude most conventional analysis methods used in eukaryotes. Here, we develop an assay based on total internal reflection-fluorescence correlation spectroscopy (TIR-FCS) to directly measure membrane fluidity in live bacteria via the diffusivity of fluorescent membrane markers. With simulations validated by experiments, we could determine how the small size, high curvature, and geometry of bacteria affect diffusion measurements and correct subsequent measurements for unbiased diffusion coefficient estimation. We used this assay to quantify the fluidity of the cytoplasmic membranes of the Gram-positive bacteria Bacillus subtilis (rod-shaped) and Staphylococcus aureus (coccus) at high (37°C) and low (20°C) temperatures in a steady state and in response to a cold shock, caused by a shift from high to low temperature. The steady-state fluidity was lower at 20°C than at 37°C, yet differed between B. subtilis and S. aureus at 37°C. Upon cold shock, the membrane fluidity decreased further below the steady-state fluidity at 20°C and recovered within 30 min in both bacterial species. Our minimally invasive assay opens up exciting perspectives for the study of a wide range of phenomena affecting the bacterial membrane, from disruption by chemicals or antibiotics to viral infection or change in nutrient availability.
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Affiliation(s)
- Aurélien Barbotin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
| | - Cyrille Billaudeau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Rut Carballido-López
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
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2
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Alonso-Roman R, Mosig AS, Figge MT, Papenfort K, Eggeling C, Schacher FH, Hube B, Gresnigt MS. Organ-on-chip models for infectious disease research. Nat Microbiol 2024; 9:891-904. [PMID: 38528150 DOI: 10.1038/s41564-024-01645-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 02/20/2024] [Indexed: 03/27/2024]
Abstract
Research on microbial pathogens has traditionally relied on animal and cell culture models to mimic infection processes in the host. Over recent years, developments in microfluidics and bioengineering have led to organ-on-chip (OoC) technologies. These microfluidic systems create conditions that are more physiologically relevant and can be considered humanized in vitro models. Here we review various OoC models and how they have been applied for infectious disease research. We outline the properties that make them valuable tools in microbiology, such as dynamic microenvironments, vascularization, near-physiological tissue constitutions and partial integration of functional immune cells, as well as their limitations. Finally, we discuss the prospects for OoCs and their potential role in future infectious disease research.
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Affiliation(s)
- Raquel Alonso-Roman
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (Leibniz-HKI), Jena, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Alexander S Mosig
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Jena, Germany
- Center for Sepsis Control and Care, Jena University Hospital, Friedrich-Schiller University, Jena, Germany
| | - Marc Thilo Figge
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Applied Systems Biology Group, Leibniz-HKI, Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Kai Papenfort
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany
| | - Christian Eggeling
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Leibniz Institute of Photonic Technology, Leibniz Center for Photonics in Infection Research e.V., Jena, Germany
- Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena Center for Soft Matter, Jena, Germany
| | - Felix H Schacher
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Jena Center for Soft Matter, Jena, Germany
- Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (Leibniz-HKI), Jena, Germany.
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany.
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University, Jena, Germany.
| | - Mark S Gresnigt
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz-HKI, Jena, Germany
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3
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Kockelkoren G, Lauritsen L, Shuttle CG, Kazepidou E, Vonkova I, Zhang Y, Breuer A, Kennard C, Brunetti RM, D'Este E, Weiner OD, Uline M, Stamou D. Molecular mechanism of GPCR spatial organization at the plasma membrane. Nat Chem Biol 2024; 20:142-150. [PMID: 37460675 PMCID: PMC10792125 DOI: 10.1038/s41589-023-01385-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 06/14/2023] [Indexed: 10/12/2023]
Abstract
G-protein-coupled receptors (GPCRs) mediate many critical physiological processes. Their spatial organization in plasma membrane (PM) domains is believed to encode signaling specificity and efficiency. However, the existence of domains and, crucially, the mechanism of formation of such putative domains remain elusive. Here, live-cell imaging (corrected for topography-induced imaging artifacts) conclusively established the existence of PM domains for GPCRs. Paradoxically, energetic coupling to extremely shallow PM curvature (<1 µm-1) emerged as the dominant, necessary and sufficient molecular mechanism of GPCR spatiotemporal organization. Experiments with different GPCRs, H-Ras, Piezo1 and epidermal growth factor receptor, suggest that the mechanism is general, yet protein specific, and can be regulated by ligands. These findings delineate a new spatiomechanical molecular mechanism that can transduce to domain-based signaling any mechanical or chemical stimulus that affects the morphology of the PM and suggest innovative therapeutic strategies targeting cellular shape.
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Affiliation(s)
- Gabriele Kockelkoren
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Line Lauritsen
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Christopher G Shuttle
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Eleftheria Kazepidou
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Vonkova
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Yunxiao Zhang
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Artù Breuer
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Celeste Kennard
- Department of Chemical Engineering, Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA
| | - Rachel M Brunetti
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
- Center for Geometrically Engineered Cellular Membranes, University of California, San Francisco, CA, USA
| | - Elisa D'Este
- Max-Planck-Institute for Medical Research, Optical Microscopy Facility, Heidelberg, Germany
| | - Orion D Weiner
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
- Center for Geometrically Engineered Cellular Membranes, University of California, San Francisco, CA, USA
| | - Mark Uline
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
- Department of Chemical Engineering, Biomedical Engineering Program, University of South Carolina, Columbia, SC, USA.
| | - Dimitrios Stamou
- Center for Geometrically Engineered Cellular Membranes, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
- Atomos Biotech, Copenhagen, Denmark.
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4
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Ebrahimi V, Stephan T, Kim J, Carravilla P, Eggeling C, Jakobs S, Han KY. Deep learning enables fast, gentle STED microscopy. Commun Biol 2023; 6:674. [PMID: 37369761 PMCID: PMC10300082 DOI: 10.1038/s42003-023-05054-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
STED microscopy is widely used to image subcellular structures with super-resolution. Here, we report that restoring STED images with deep learning can mitigate photobleaching and photodamage by reducing the pixel dwell time by one or two orders of magnitude. Our method allows for efficient and robust restoration of noisy 2D and 3D STED images with multiple targets and facilitates long-term imaging of mitochondrial dynamics.
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Affiliation(s)
- Vahid Ebrahimi
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL, USA
| | - Till Stephan
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Jiah Kim
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Pablo Carravilla
- Leibniz Institute of Photonic Technology e.V., Jena, Germany, member of the Leibniz Centre for Photonics in Infection Research (LPI), Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Christian Eggeling
- Leibniz Institute of Photonic Technology e.V., Jena, Germany, member of the Leibniz Centre for Photonics in Infection Research (LPI), Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
- Translational Neuroinflammation and Automated Microscopy, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Göttingen, Germany
| | - Kyu Young Han
- CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL, USA.
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5
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Regulation of membrane protein structure and function by their lipid nano-environment. Nat Rev Mol Cell Biol 2023; 24:107-122. [PMID: 36056103 PMCID: PMC9892264 DOI: 10.1038/s41580-022-00524-4] [Citation(s) in RCA: 121] [Impact Index Per Article: 121.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 02/04/2023]
Abstract
Transmembrane proteins comprise ~30% of the mammalian proteome, mediating metabolism, signalling, transport and many other functions required for cellular life. The microenvironment of integral membrane proteins (IMPs) is intrinsically different from that of cytoplasmic proteins, with IMPs solvated by a compositionally and biophysically complex lipid matrix. These solvating lipids affect protein structure and function in a variety of ways, from stereospecific, high-affinity protein-lipid interactions to modulation by bulk membrane properties. Specific examples of functional modulation of IMPs by their solvating membranes have been reported for various transporters, channels and signal receptors; however, generalizable mechanistic principles governing IMP regulation by lipid environments are neither widely appreciated nor completely understood. Here, we review recent insights into the inter-relationships between complex lipidomes of mammalian membranes, the membrane physicochemical properties resulting from such lipid collectives, and the regulation of IMPs by either or both. The recent proliferation of high-resolution methods to study such lipid-protein interactions has led to generalizable insights, which we synthesize into a general framework termed the 'functional paralipidome' to understand the mutual regulation between membrane proteins and their surrounding lipid microenvironments.
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6
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Ebrahimi V, Stephan T, Kim J, Carravilla P, Eggeling C, Jakobs S, Han KY. Deep learning enables fast, gentle STED microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023. [PMID: 36747618 PMCID: PMC9900922 DOI: 10.1101/2023.01.26.525571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
STED microscopy is widely used to image subcellular structures with super-resolution. Here, we report that denoising STED images with deep learning can mitigate photobleaching and photodamage by reducing the pixel dwell time by one or two orders of magnitude. Our method allows for efficient and robust restoration of noisy 2D and 3D STED images with multiple targets and facilitates long-term imaging of mitochondrial dynamics.
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7
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Andersen C, Zulueta Díaz YDLM, Kure JL, Hessellund Eriksen M, Lovatt AL, Lagerholm C, Morales S, Sehayek S, Sheard TMD, Wiseman PW, Arnspang EC. Angiotensin II Treatment Induces Reorganization and Changes in the Lateral Dynamics of Angiotensin II Type 1 Receptor in the Plasma Membrane Elucidated by Photoactivated Localization Microscopy Combined with Image Spatial Correlation Analysis. Anal Chem 2023; 95:730-738. [PMID: 36574961 DOI: 10.1021/acs.analchem.2c02720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mechanisms by which angiotensin II type 1 receptor is distributed and the diffusional pattern in the plasma membrane (PM) remain unclear, despite their crucial role in cardiovascular homeostasis. In this work, we obtained quantitative information of angiotensin II type 1 receptor (AT1R) lateral dynamics as well as changes in the diffusion properties after stimulation with ligands in living cells using photoactivated localization microscopy (PALM) combined with image spatial-temporal correlation analysis. To study the organization of the receptor at the nanoscale, expansion microscopy (ExM) combined with PALM was performed. This study revealed that AT1R lateral diffusion increased after binding to angiotensin II (Ang II) and the receptor diffusion was transiently confined in the PM. In addition, ExM revealed that AT1R formed nanoclusters at the PM and the cluster size significantly decreased after Ang II treatment. Taking these results together suggest that Ang II binding and activation cause reorganization and changes in the dynamics of AT1R at the PM.
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Affiliation(s)
- Camilla Andersen
- SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Odense M5230, Denmark
| | | | - Jakob L Kure
- SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Odense M5230, Denmark
| | - Mathias Hessellund Eriksen
- SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Odense M5230, Denmark
| | - Adam Leslie Lovatt
- SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Odense M5230, Denmark
| | | | - Sebastian Morales
- Department of Physics and Department of Chemistry, McGill University, MontrealH3A 0B8, Canada
| | - Simon Sehayek
- Department of Physics and Department of Chemistry, McGill University, MontrealH3A 0B8, Canada
| | - Thomas M D Sheard
- School of Biosciences, University of Sheffield, SheffieldS10 2TN, U.K
| | - Paul W Wiseman
- Department of Physics and Department of Chemistry, McGill University, MontrealH3A 0B8, Canada
| | - Eva C Arnspang
- SDU Biotechnology, Department of Green Technology, University of Southern Denmark, Odense M5230, Denmark
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8
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A biophysical perspective of the regulatory mechanisms of ezrin/radixin/moesin proteins. Biophys Rev 2022; 14:199-208. [PMID: 35340609 PMCID: PMC8921360 DOI: 10.1007/s12551-021-00928-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/14/2021] [Indexed: 02/08/2023] Open
Abstract
Many signal transductions resulting from ligand-receptor interactions occur at the cell surface. These signaling pathways play essential roles in cell polarization, membrane morphogenesis, and the modulation of membrane tension at the cell surface. However, due to the large number of membrane-binding proteins, including actin-membrane linkers, and transmembrane proteins present at the cell surface, the molecular mechanisms underlying the regulation at the cell surface are yet unclear. Here, we describe the molecular functions of one of the key players at the cell surface, ezrin/radixin/moesin (ERM) proteins from a biophysical point of view. We focus our discussion on biophysical properties of ERM proteins revealed by using biophysical tools in live cells and in vitro reconstitution systems. We first describe the structural properties of ERM proteins and then discuss the interactions of ERM proteins with PI(4,5)P2 and the actin cytoskeleton. These properties of ERM proteins revealed by using biophysical approaches have led to a better understanding of their physiological functions in cells and tissues. Supplementary Information The online version contains supplementary material available at 10.1007/s12551-021-00928-0.
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9
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Zhao Z, Roy D, Steinkühler J, Robinson T, Lipowsky R, Dimova R. Super-Resolution Imaging of Highly Curved Membrane Structures in Giant Vesicles Encapsulating Molecular Condensates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106633. [PMID: 34710248 DOI: 10.1002/adma.202106633] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Molecular crowding is an inherent feature of cell interiors. Synthetic cells as provided by giant unilamellar vesicles (GUVs) encapsulating macromolecules (poly(ethylene glycol) and dextran) represent an excellent mimetic system to study membrane transformations associated with molecular crowding and protein condensation. Similarly to cells, such GUVs exhibit highly curved structures like nanotubes. Upon liquid-liquid phase separation their membrane deforms into apparent kinks at the contact line of the interface between the two aqueous phases. These structures, nanotubes, and kinks, have dimensions below optical resolution. Here, these are studied with super-resolution stimulated emission depletion (STED) microscopy facilitated by immobilization in a microfluidic device. The cylindrical nature of the nanotubes based on the superior resolution of STED and automated data analysis is demonstrated. The deduced membrane spontaneous curvature is in excellent agreement with theoretical predictions. Furthermore, the membrane kink-like structure is resolved as a smoothly curved membrane demonstrating the existence of the intrinsic contact angle, which describes the wettability contrast of the encapsulated phases to the membrane. Resolving these highly curved membrane structures with STED imaging provides important insights in the membrane properties and interactions underlying cellular activities.
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Affiliation(s)
- Ziliang Zhao
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743, Jena, Germany
| | - Debjit Roy
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Jan Steinkühler
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Tom Robinson
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Reinhard Lipowsky
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
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10
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Carravilla P, Dasgupta A, Zhurgenbayeva G, Danylchuk DI, Klymchenko AS, Sezgin E, Eggeling C. Long-term STED imaging of membrane packing and dynamics by exchangeable polarity-sensitive dyes. BIOPHYSICAL REPORTS 2021; 1:None. [PMID: 34939048 PMCID: PMC8651516 DOI: 10.1016/j.bpr.2021.100023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/08/2021] [Indexed: 12/28/2022]
Abstract
Understanding the plasma membrane nanoscale organization and dynamics in living cells requires microscopy techniques with high spatial and temporal resolution that permit for long acquisition times and allow for the quantification of membrane biophysical properties, such as lipid ordering. Among the most popular super-resolution techniques, stimulated emission depletion (STED) microscopy offers one of the highest temporal resolutions, ultimately defined by the scanning speed. However, monitoring live processes using STED microscopy is significantly limited by photobleaching, which recently has been circumvented by exchangeable membrane dyes that only temporarily reside in the membrane. Here, we show that NR4A, a polarity-sensitive exchangeable plasma membrane probe based on Nile red, permits the super-resolved quantification of membrane biophysical parameters in real time with high temporal and spatial resolution as well as long acquisition times. The potential of this polarity-sensitive exchangeable dye is showcased by live-cell real-time three-dimensional STED recordings of bleb formation and lipid exchange during membrane fusion as well as by STED-fluorescence correlation spectroscopy experiments for the simultaneous quantification of membrane dynamics and lipid packing that correlate in model and live-cell membranes.
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Affiliation(s)
- Pablo Carravilla
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Anindita Dasgupta
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
| | - Gaukhar Zhurgenbayeva
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
| | - Dmytro I. Danylchuk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Andrey S. Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Illkirch, France
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden
| | - Christian Eggeling
- Leibniz Institute of Photonic Technology e.V., Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, Jena, Germany
- Jena School for Microbial Communication, Friedrich Schiller University Jena, Jena, Germany
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Jena Center for Soft Matter, Jena, Germany
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11
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Lipid Self-Assemblies under the Atomic Force Microscope. Int J Mol Sci 2021; 22:ijms221810085. [PMID: 34576248 PMCID: PMC8467407 DOI: 10.3390/ijms221810085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 12/13/2022] Open
Abstract
Lipid model membranes are important tools in the study of biophysical processes such as lipid self-assembly and lipid–lipid interactions in cell membranes. The use of model systems to adequate and modulate complexity helps in the understanding of many events that occur in cellular membranes, that exhibit a wide variety of components, including lipids of different subfamilies (e.g., phospholipids, sphingolipids, sterols…), in addition to proteins and sugars. The capacity of lipids to segregate by themselves into different phases at the nanoscale (nanodomains) is an intriguing feature that is yet to be fully characterized in vivo due to the proposed transient nature of these domains in living systems. Model lipid membranes, instead, have the advantage of (usually) greater phase stability, together with the possibility of fully controlling the system lipid composition. Atomic force microscopy (AFM) is a powerful tool to detect the presence of meso- and nanodomains in a lipid membrane. It also allows the direct quantification of nanomechanical resistance in each phase present. In this review, we explore the main kinds of lipid assemblies used as model membranes and describe AFM experiments on model membranes. In addition, we discuss how these assemblies have extended our knowledge of membrane biophysics over the last two decades, particularly in issues related to the variability of different model membranes and the impact of supports/cytoskeleton on lipid behavior, such as segregated domain size or bilayer leaflet uncoupling.
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12
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Siegmund R, Werner F, Jakobs S, Geisler C, Egner A. isoSTED microscopy with water-immersion lenses and background reduction. Biophys J 2021; 120:3303-3314. [PMID: 34246627 PMCID: PMC8392127 DOI: 10.1016/j.bpj.2021.05.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 01/17/2023] Open
Abstract
Fluorescence microscopy is an excellent tool to gain knowledge on cellular structures and biochemical processes. Stimulated emission depletion (STED) microscopy provides a resolution in the range of a few 10 nm at relatively fast data acquisition. As cellular structures can be oriented in any direction, it is of great benefit if the microscope exhibits an isotropic resolution. Here, we present an isoSTED microscope that utilizes water-immersion objective lenses and enables imaging of cellular structures with an isotropic resolution of better than 60 nm in living samples at room temperature and without CO2 supply or another pH control. This corresponds to a reduction of the focal volume by far more than two orders of magnitude as compared to confocal microscopy. The imaging speed is in the range of 0.8 s/μm3. Because fluorescence signal can only be detected from a diffraction-limited volume, a background signal is inevitably observed at resolutions well beyond the diffraction limit. Therefore, we additionally present a method that allows us to identify this unspecific background signal and to remove it from the image.
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Affiliation(s)
- René Siegmund
- Department of Optical Nanoscopy, Institute for Nanophotonics Göttingen, Göttingen, Germany
| | - Frank Werner
- Institute of Mathematics, University of Würzburg, Würzburg, Germany
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Claudia Geisler
- Department of Optical Nanoscopy, Institute for Nanophotonics Göttingen, Göttingen, Germany
| | - Alexander Egner
- Department of Optical Nanoscopy, Institute for Nanophotonics Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
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Wu Z, Xu X, Xi P. Stimulated emission depletion microscopy for biological imaging in four dimensions: A review. Microsc Res Tech 2021; 84:1947-1958. [PMID: 33713513 DOI: 10.1002/jemt.23750] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 02/27/2021] [Indexed: 12/26/2022]
Abstract
Stimulated emission depletion (STED) microscopy allows high lateral and axial resolution, long term imaging in living cells. Here we review recent technical advances in STED microscopy, with emphasis on resolution and measurement range of XYZt four dimensions. Different STED technical advances and novel STED probes are discussed with their respective application in biological subcellular imaging. This review may serve as a practical guide for choosing a suitable approach to the advanced STED super-resolution imaging.
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Affiliation(s)
- Zhaoyang Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Xinzhu Xu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Peng Xi
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China.,UTS-SUSTech Joint Research Centre for Biomedical Materials and Devices, Department of Biomedical Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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14
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Lamerton RE, Lightfoot A, Nieves DJ, Owen DM. The Role of Protein and Lipid Clustering in Lymphocyte Activation. Front Immunol 2021; 12:600961. [PMID: 33767692 PMCID: PMC7986720 DOI: 10.3389/fimmu.2021.600961] [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: 08/31/2020] [Accepted: 02/12/2021] [Indexed: 12/30/2022] Open
Abstract
Lymphocytes must strike a delicate balance between activating in response to signals from potentially pathogenic organisms and avoiding activation from stimuli emanating from the body's own cells. For cells, such as T or B cells, maximizing the efficiency and fidelity, whilst minimizing the crosstalk, of complex signaling pathways is crucial. One way of achieving this control is by carefully orchestrating the spatiotemporal organization of signaling molecules, thereby regulating the rates of protein-protein interactions. This is particularly true at the plasma membrane where proximal signaling events take place and the phenomenon of protein microclustering has been extensively observed and characterized. This review will focus on what is known about the heterogeneous distribution of proteins and lipids at the cell surface, illustrating how such distributions can influence signaling in health and disease. We particularly focus on nanoscale molecular organization, which has recently become accessible for study through advances in microscope technology and analysis methodology.
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Affiliation(s)
- Rachel E Lamerton
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Abbey Lightfoot
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Daniel J Nieves
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
| | - Dylan M Owen
- Institute of Immunology and Immunotherapy, School of Mathematics and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, United Kingdom
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15
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Bernabé-Rubio M, Bosch-Fortea M, García E, Bernardino de la Serna J, Alonso MA. Adaptive Lipid Immiscibility and Membrane Remodeling Are Active Functional Determinants of Primary Ciliogenesis. SMALL METHODS 2021; 5:e2000711. [PMID: 34927881 DOI: 10.1002/smtd.202000711] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/11/2020] [Indexed: 06/14/2023]
Abstract
Lipid liquid-liquid immiscibility and its consequent lateral heterogeneity have been observed under thermodynamic equilibrium in model and native membranes. However, cholesterol-rich membrane domains, sometimes referred to as lipid rafts, are difficult to observe spatiotemporally in live cells. Despite their importance in many biological processes, robust evidence for their existence remains elusive. This is mainly due to the difficulty in simultaneously determining their chemical composition and physicochemical nature, whilst spatiotemporally resolving their nanodomain lifetime and molecular dynamics. In this study, a bespoke method based on super-resolution stimulated emission depletion (STED) microscopy and raster imaging correlation spectroscopy (RICS) is used to overcome this issue. This methodology, laser interleaved confocal RICS and STED-RICS (LICSR), enables simultaneous tracking of lipid lateral packing and dynamics at the nanoscale. Previous work indicated that, in polarized epithelial cells, the midbody remnant licenses primary cilium formation through an unidentified mechanism. LICSR shows that lipid immiscibility and its adaptive collective nanoscale self-assembly are crucial for the midbody remnant to supply condensed membranes to the centrosome for the biogenesis of the ciliary membrane. Hence, this work poses a breakthrough in the field of lipid biology by providing compelling evidence of a functional role for liquid ordered-like membranes in primary ciliogenesis.
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Affiliation(s)
- Miguel Bernabé-Rubio
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, 28049, Spain
- King's College London Centre for Stem Cells and Regenerative Medicine, 28th Floor, Tower Wing, Guy's Campus, Great Maze Pond, London, SE1 9RT, UK
| | - Minerva Bosch-Fortea
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, 28049, Spain
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK
| | - Esther García
- Central Laser Facility, Rutherford Appleton Laboratory, MRC-Research Complex at Harwell, Science and Technology Facilities Council, Harwell, OX11 0QX, UK
- CR-UK Beatson Institute, Switchback Road, Glasgow, G61 1BD, UK
| | - Jorge Bernardino de la Serna
- Central Laser Facility, Rutherford Appleton Laboratory, MRC-Research Complex at Harwell, Science and Technology Facilities Council, Harwell, OX11 0QX, UK
- National Heart and Lung Institute, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, UK
- NIHR Imperial Biomedical Research Centre, London, SW7 2AZ, UK
| | - Miguel A Alonso
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, 28049, Spain
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16
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Xin W, Zhang Q, Gu M. Inverse design of optical needles with central zero-intensity points by artificial neural networks. OPTICS EXPRESS 2020; 28:38718-38732. [PMID: 33379435 DOI: 10.1364/oe.410073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Optical needles with central zero-intensity points have attracted much attention in the field of 3D super-resolution microscopy, optical lithography, optical storage and Raman spectroscopy. Nevertheless, most of the studies create few types of optical needles with central zero-intensity points based on the theory and intuition with time-consuming parameter sweeping and complex pre-select of parameters. Here, we report on the inverse design of optical needles with central zero-intensity points by dipole-based artificial neural networks (DANNs), permitting the creation of needles which are close to specific length and amplitude. The resolution of these optical needles with central zero-intensity points is close to axial diffraction limit (∼1λ). Additionally, the DANNs can realize the inverse design of several types on-axis distributions, such as optical needles and multifocal distributions.
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