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Holler C, Taylor RW, Schambony A, Möckl L, Sandoghdar V. A paintbrush for delivery of nanoparticles and molecules to live cells with precise spatiotemporal control. Nat Methods 2024; 21:512-520. [PMID: 38347139 PMCID: PMC10927540 DOI: 10.1038/s41592-024-02177-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 01/08/2024] [Indexed: 03/13/2024]
Abstract
Delivery of very small amounts of reagents to the near-field of cells with micrometer spatial precision and millisecond time resolution is currently out of reach. Here we present μkiss as a micropipette-based scheme for brushing a layer of small molecules and nanoparticles onto the live cell membrane from a subfemtoliter confined volume of a perfusion flow. We characterize our system through both experiments and modeling, and find excellent agreement. We demonstrate several applications that benefit from a controlled brush delivery, such as a direct means to quantify local and long-range membrane mobility and organization as well as dynamical probing of intercellular force signaling.
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Affiliation(s)
- Cornelia Holler
- Max Planck Institute for the Science of Light, Erlangen, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
- Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Richard William Taylor
- Max Planck Institute for the Science of Light, Erlangen, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Alexandra Schambony
- Max Planck Institute for the Science of Light, Erlangen, Germany
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
- Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Leonhard Möckl
- Max Planck Institute for the Science of Light, Erlangen, Germany
| | - Vahid Sandoghdar
- Max Planck Institute for the Science of Light, Erlangen, Germany.
- Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany.
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
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2
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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3
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Hargreaves R, Duwé S, Rozario AM, Funston AM, Tabor RF, Dedecker P, Whelan DR, Bell TDM. Live-Cell SOFI Correlation with SMLM and AFM Imaging. ACS BIO & MED CHEM AU 2023; 3:261-269. [PMID: 37363082 PMCID: PMC10288496 DOI: 10.1021/acsbiomedchemau.2c00086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 06/28/2023]
Abstract
Standard optical imaging is diffraction-limited and lacks the resolving power to visualize many of the organelles and proteins found within the cell. The advent of super-resolution techniques overcame this barrier, enabling observation of subcellular structures down to tens of nanometers in size; however these techniques require or are typically applied to fixed samples. This raises the question of how well a fixed-cell image represents the system prior to fixation. Here we present the addition of live-cell Super-Resolution Optical Fluctuation Imaging (SOFI) to a previously reported correlative process using Single Molecule Localization Microscopy (SMLM) and Atomic Force Microscopy (AFM). SOFI was used with fluorescent proteins and low laser power to observe cellular ultrastructure in live COS-7 cells. SOFI-SMLM-AFM of microtubules showed minimal changes to the microtubule network in the 20 min between live-cell SOFI and fixation. Microtubule diameters were also analyzed through all microscopies; SOFI found diameters of 249 ± 68 nm and SMLM was 71 ± 33 nm. AFM height measurements found microtubules to protrude 26 ± 13 nm above the surrounding cellular material. The correlation of SMLM and AFM was extended to two-color SMLM to image both microtubules and actin. Two target SOFI was performed with various fluorescent protein combinations. rsGreen1-rsKAME, rsGreen1-Dronpa, and ffDronpaF-rsKAME fluorescent protein combinations were determined to be suitable for two target SOFI imaging. This correlative application of super-resolution live-cell and fixed-cell imaging revealed minimal artifacts created for the imaged target structures through the sample preparation procedure and emphasizes the power of correlative microscopy.
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Affiliation(s)
| | - Sam Duwé
- Advanced
Optical Microscopy Centre, Hasselt University, Diepenbeek 3590, Belgium
| | - Ashley M. Rozario
- Department
of Rural Clinical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo 3552, Victoria, Australia
| | - Alison M. Funston
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
- ARC
Centre of Excellence in Exciton Science, Monash University, Clayton, Victoria 3800, Australia
| | - Rico F. Tabor
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
| | - Peter Dedecker
- Department
of Chemistry, KU Leuven, Leuven 3001, Belgium
| | - Donna R. Whelan
- Department
of Rural Clinical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo 3552, Victoria, Australia
| | - Toby D. M. Bell
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
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4
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Guru A, Saravanan S, Sharma D, Narasimha M. The microtubule end-binding proteins EB1 and Patronin modulate the spatiotemporal dynamics of myosin and pattern pulsed apical constriction. Development 2022; 149:284823. [PMID: 36440630 DOI: 10.1242/dev.199759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/31/2022] [Indexed: 11/29/2022]
Abstract
Apical constriction powers amnioserosa contraction during Drosophila dorsal closure. The nucleation, movement and dispersal of apicomedial actomyosin complexes generates pulsed apical constrictions during early closure. Persistent apicomedial and circumapical actomyosin complexes drive unpulsed constrictions that follow. Here, we show that the microtubule end-binding proteins EB1 and Patronin pattern constriction dynamics and contraction kinetics by coordinating the balance of actomyosin forces in the apical plane. We find that microtubule growth from moving Patronin platforms governs the spatiotemporal dynamics of apicomedial myosin through the regulation of RhoGTPase signaling by transient EB1-RhoGEF2 interactions. We uncover the dynamic reorganization of a subset of short non-centrosomally nucleated apical microtubules that surround the coalescing apicomedial myosin complex, trail behind it as it moves and disperse as the complex dissolves. We demonstrate that apical microtubule reorganization is sensitive to Patronin levels. Microtubule depolymerization compromised apical myosin enrichment and altered constriction dynamics. Together, our findings uncover the importance of reorganization of an intact apical microtubule meshwork, by moving Patronin platforms and growing microtubule ends, in enabling the spatiotemporal modulation of actomyosin contractility and, through it, apical constriction.
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Affiliation(s)
- Anwesha Guru
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
| | - Surat Saravanan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
| | - Deepanshu Sharma
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
| | - Maithreyi Narasimha
- Department of Biological Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India
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Hargreaves RB, Rozario AM, McCoy TM, Meaney SP, Funston AM, Tabor RF, Whelan DR, Bell TD. Optimising correlative super resolution and atomic force microscopies for investigating the cellular cytoskeleton. Methods Appl Fluoresc 2022; 10. [DOI: 10.1088/2050-6120/ac8526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/28/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Correlative imaging methods can provide greater information for investigations of cellular ultra-structure, with separate analysis methods complementing each other’s strengths and covering for deficiencies. Here we present a method for correlative applications of super resolution and atomic force microscopies, optimising the sample preparation for correlative imaging of the cellular cytoskeleton in COS-7 cells. This optimisation determined the order of permeabilisation and fixation, the concentration of Triton X-100 surfactant used and time required for sufficient removal of the cellular membrane while maintaining the microtubule network. Correlative SMLM/AFM imaging revealed the different information that can be obtained through each microscopy. The widths of microtubules and microtubule clusters were determined from both AFM height measurements and Gaussian fitting of SMLM intensity cross sections, these were then compared to determine the orientation of microtubules within larger microtubule bundles. The ordering of microtubules at intersections was determined from the AFM height profiles as each microtubule crosses the other. The combination of both microtubule diameter measurements enabled greater information on their structure to be found than either measurement could individually.
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Rozario AM, Morey A, Elliott C, Russ B, Whelan DR, Turner SJ, Bell TDM. 3D Single Molecule Super-Resolution Microscopy of Whole Nuclear Lamina. Front Chem 2022; 10:863610. [PMID: 35572104 PMCID: PMC9096160 DOI: 10.3389/fchem.2022.863610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/28/2022] [Indexed: 12/02/2022] Open
Abstract
Single molecule (SM) super-resolution microscopies bypass the diffraction limit of conventional optical techniques and provide excellent spatial resolutions in the tens of nanometers without overly complex microscope hardware. SM imaging using optical astigmatism is an efficient strategy for visualizing subcellular features in 3D with a z-range of up to ∼1 µm per acquisition. This approach however, places high demands on fluorophore brightness and photoswitching resilience meaning that imaging entire cell volumes in 3D using SM super-resolution remains challenging. Here we employ SM astigmatism together with multiplane acquisition to visualize the whole nuclear lamina of COS-7 and T cells in 3D. Nuclear lamina provides structural support to the nuclear envelope and participates in vital nuclear functions including internuclear transport, chromatin organization and gene regulation. Its position at the periphery of the nucleus provides a visible reference of the nuclear boundary and can be used to quantify the spatial distribution of intranuclear components such as histone modifications and transcription factors. We found Alexa Fluor 647, a popular photoswitchable fluorophore, remained viable for over an hour of continuous high laser power exposure, and provided sufficient brightness detectable up to 8 µm deep into a cell, allowing us to capture the entire nuclear lamina in 3D. Our approach provides sufficient super-resolution detail of nuclear lamina morphology to enable quantification of overall nuclear dimensions and local membrane features.
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Affiliation(s)
- Ashley M. Rozario
- School of Chemistry, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
| | - Alison Morey
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
| | - Cade Elliott
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Brendan Russ
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
| | - Donna R. Whelan
- La Trobe Institute for Molecular Science, Bendigo, VIC, Australia
| | - Stephen J. Turner
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
- *Correspondence: Stephen J. Turner, ; Toby D. M. Bell,
| | - Toby D. M. Bell
- School of Chemistry, Monash University, Clayton, VIC, Australia
- *Correspondence: Stephen J. Turner, ; Toby D. M. Bell,
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