1
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Heydecker M, Shitara A, Chen D, Tran DT, Masedunskas A, Tora MS, Ebrahim S, Appaduray MA, Galeano Niño JL, Bhardwaj A, Narayan K, Hardeman EC, Gunning PW, Weigert R. Coordination of force-generating actin-based modules stabilizes and remodels membranes in vivo. J Cell Biol 2024; 223:e202401091. [PMID: 39172125 PMCID: PMC11344176 DOI: 10.1083/jcb.202401091] [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: 01/18/2024] [Revised: 06/18/2024] [Accepted: 08/07/2024] [Indexed: 08/23/2024] Open
Abstract
Membrane remodeling drives a broad spectrum of cellular functions, and it is regulated through mechanical forces exerted on the membrane by cytoplasmic complexes. Here, we investigate how actin filaments dynamically tune their structure to control the active transfer of membranes between cellular compartments with distinct compositions and biophysical properties. Using intravital subcellular microscopy in live rodents we show that a lattice composed of linear filaments stabilizes the granule membrane after fusion with the plasma membrane and a network of branched filaments linked to the membranes by Ezrin, a regulator of membrane tension, initiates and drives to completion the integration step. Our results highlight how the actin cytoskeleton tunes its structure to adapt to dynamic changes in the biophysical properties of membranes.
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Affiliation(s)
- Marco Heydecker
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- School of Biomedical Sciences, University of New South Wales Sydney, Sydney, Australia
| | - Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Department of Pharmacology, Asahi University School of Dentistry, Gifu, Japan
| | - Desu Chen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Duy T Tran
- NIDCR Imaging Core, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Andrius Masedunskas
- School of Biomedical Sciences, University of New South Wales Sydney, Sydney, Australia
| | - Muhibullah S Tora
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Mark A Appaduray
- School of Biomedical Sciences, University of New South Wales Sydney, Sydney, Australia
| | - Jorge Luis Galeano Niño
- EMBL Australia, Single Molecule Science node, University of New South Wales Sydney, Sydney, Australia
| | - Abhishek Bhardwaj
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Edna C Hardeman
- School of Biomedical Sciences, University of New South Wales Sydney, Sydney, Australia
| | - Peter W Gunning
- School of Biomedical Sciences, University of New South Wales Sydney, Sydney, Australia
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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2
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Vaghela R, Arkudas A, Horch RE, Hessenauer M. Actually Seeing What Is Going on - Intravital Microscopy in Tissue Engineering. Front Bioeng Biotechnol 2021; 9:627462. [PMID: 33681162 PMCID: PMC7925911 DOI: 10.3389/fbioe.2021.627462] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/26/2021] [Indexed: 12/21/2022] Open
Abstract
Intravital microscopy (IVM) study approach offers several advantages over in vitro, ex vivo, and 3D models. IVM provides real-time imaging of cellular events, which provides us a comprehensive picture of dynamic processes. Rapid improvement in microscopy techniques has permitted deep tissue imaging at a higher resolution. Advances in fluorescence tagging methods enable tracking of specific cell types. Moreover, IVM can serve as an important tool to study different stages of tissue regeneration processes. Furthermore, the compatibility of different tissue engineered constructs can be analyzed. IVM is also a promising approach to investigate host reactions on implanted biomaterials. IVM can provide instant feedback for improvising tissue engineering strategies. In this review, we aim to provide an overview of the requirements and applications of different IVM approaches. First, we will discuss the history of IVM development, and then we will provide an overview of available optical modalities including the pros and cons. Later, we will summarize different fluorescence labeling methods. In the final section, we will discuss well-established chronic and acute IVM models for different organs.
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Affiliation(s)
- Ravikumar Vaghela
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Maximilian Hessenauer
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
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3
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Zamora A, Moris M, Silva R, Deschaume O, Bartic C, Parac-Vogt TN, Verbiest T. Visualization and characterization of metallo-aggregates using multi-photon microscopy. RSC Adv 2021; 11:657-661. [PMID: 35423665 PMCID: PMC8693374 DOI: 10.1039/d0ra07263j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/17/2020] [Indexed: 11/26/2022] Open
Abstract
A simple and cost-effective method based on multi-photon microscopy is presented for the preliminary screening of the general morphology, size range and heterogeneity of Ir(iii) nano-aggregate formulations. Multi-photon microscopy can be an excellent complementary technique for the characterization of nano-aggregates containing metallic photosensitizers with multi-photon emission properties.![]()
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Affiliation(s)
- Ana Zamora
- Molecular Imaging and Photonics
- KU Leuven
- Belgium
| | | | - Rui Silva
- Molecular Imaging and Photonics
- KU Leuven
- Belgium
- Engineering Faculty of Oporto University
- Portugal (FEUP)
| | | | - Carmen Bartic
- Laboratory of Soft Matter and Biophysics
- KU Leuven
- Belgium
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4
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Akkaya B, Kamenyeva O, Kabat J, Kissinger R. Visualizing the Dynamics of T Cell-Dendritic Cell Interactions in Intact Lymph Nodes by Multiphoton Confocal Microscopy. Methods Mol Biol 2021; 2304:243-263. [PMID: 34028721 PMCID: PMC9998166 DOI: 10.1007/978-1-0716-1402-0_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Multiphoton microscopy has provided us the ability to visualize cell behavior and biology in intact organs due to its superiority in reaching deep into tissues. Because skin draining lymph nodes are readily accessible via minimal surgery, it is possible to characterize the intricate interactions taking place in peripheral lymph nodes intravitally. Here we describe our protocol to visualize antigen-specific T cell-dendritic cell interactions in the popliteal lymph node of immunocompetent mice. With this method, behaviors of up to four cell types, such as T cells with different antigen specificities, T cells differentiated into different effector and regulatory lineages and dendritic cells originating from mice that bear mutations in functional genes can be imaged simultaneously.
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Affiliation(s)
- Billur Akkaya
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Olena Kamenyeva
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Juraj Kabat
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ryan Kissinger
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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5
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Shitara A, Bleck CKE, Weigert R. Cdc42 controls secretory granules morphology in rodent salivary glands in vivo. Commun Integr Biol 2020; 13:22-26. [PMID: 32128025 PMCID: PMC7039664 DOI: 10.1080/19420889.2020.1724605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 10/27/2022] Open
Abstract
We previously reported that the small GTPase Cdc42 negatively regulates endocytosis in the salivary gland of live mice. By using intravital subcellular microscopy, we showed that depletion of Cdc42 causes the mis-sorting of plasma membrane components into intracellular vesicles, ultimately leading to the impairment of the homeostasis of the apical plasma membrane. In this study, we report that, besides, Cdc42 depletion alters the ultrastructure of large secretory granules analyzed by transmission electron microscopy. We found that lack of Cdc42 increases the number of granules per cell and alters their structure. Specifically, granules are smaller, less circular and exhibit heterogeneous electron densities in their lumen. Our findings suggest a novel role for Cdc42 in controlling granule biogenesis and/or maturation.
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Affiliation(s)
- Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Intracellular Membrane Trafficking Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Department of Pharmacology, Asahi University School of Dentistry, Mizuho, Japan
| | - Christopher K E Bleck
- Electron Microscopy Core Facility, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.,Intracellular Membrane Trafficking Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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6
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Shitara A, Malec L, Ebrahim S, Chen D, Bleck C, Hoffman MP, Weigert R. Cdc42 negatively regulates endocytosis during apical membrane maintenance in live animals. Mol Biol Cell 2018; 30:324-332. [PMID: 30540520 PMCID: PMC6589572 DOI: 10.1091/mbc.e18-10-0615] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Lumen establishment and maintenance are fundamental for tubular organs physiological functions. Most of the studies investigating the mechanisms regulating this process have been carried out in cell cultures or in smaller organisms, whereas little has been done in mammalian model systems in vivo. Here we used the salivary glands of live mice to examine the role of the small GTPase Cdc42 in the regulation of the homeostasis of the intercellular canaliculi, a specialized apical domain of the acinar cells, where protein and fluid secretion occur. Depletion of Cdc42 in adult mice induced a significant expansion of the apical canaliculi, whereas depletion at late embryonic stages resulted in a complete inhibition of their postnatal formation. In addition, intravital subcellular microscopy revealed that reduced levels of Cdc42 affected membrane trafficking from and toward the plasma membrane, highlighting a novel role for Cdc42 in membrane remodeling through the negative regulation of selected endocytic pathways.
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Affiliation(s)
- Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lenka Malec
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Desu Chen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.,College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, MD 20742
| | - Christopher Bleck
- Electron Microscopy Core Facility, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Matthew P Hoffman
- Matrix and Morphogenesis Section, National Institutes of Health, Bethesda, MD 20892
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.,Intracellular Membrane Trafficking Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
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7
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Duan X, Li H, Li X, Oldham KR, Wang TD. Axial beam scanning in multiphoton microscopy with MEMS-based actuator. OPTICS EXPRESS 2017; 25:2195-2205. [PMID: 29519067 PMCID: PMC5772401 DOI: 10.1364/oe.25.002195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We demonstrate a remotely located microelectromechanical systems (MEMS) actuator that can translate >400 μm to perform axial beam scanning in a multiphoton microscope. We use a 2-dimensional MEMS mirror for lateral scanning, and collected multiphoton excited fluorescence images in either the horizontal or vertical plane with a field-of-view of either 270 × 270 or 270 × 200 μm2, respectively, at 5 frames per second. Axial resolution varied from 4.5 to 7 μm over the scan range. The compact size of the actuator and scanner allows for use in an endomicroscope to collect images in the vertical plane with >200 μm depth.
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Affiliation(s)
- Xiyu Duan
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Haijun Li
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Xue Li
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Kenn R. Oldham
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Thomas D. Wang
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
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8
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Appaduray MA, Masedunskas A, Bryce NS, Lucas CA, Warren SC, Timpson P, Stear JH, Gunning PW, Hardeman EC. Recruitment Kinetics of Tropomyosin Tpm3.1 to Actin Filament Bundles in the Cytoskeleton Is Independent of Actin Filament Kinetics. PLoS One 2016; 11:e0168203. [PMID: 27977753 PMCID: PMC5158027 DOI: 10.1371/journal.pone.0168203] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 11/28/2016] [Indexed: 12/23/2022] Open
Abstract
The actin cytoskeleton is a dynamic network of filaments that is involved in virtually every cellular process. Most actin filaments in metazoa exist as a co-polymer of actin and tropomyosin (Tpm) and the function of an actin filament is primarily defined by the specific Tpm isoform associated with it. However, there is little information on the interdependence of these co-polymers during filament assembly and disassembly. We addressed this by investigating the recovery kinetics of fluorescently tagged isoform Tpm3.1 into actin filament bundles using FRAP analysis in cell culture and in vivo in rats using intracellular intravital microscopy, in the presence or absence of the actin-targeting drug jasplakinolide. The mobile fraction of Tpm3.1 is between 50% and 70% depending on whether the tag is at the C- or N-terminus and whether the analysis is in vivo or in cultured cells. We find that the continuous dynamic exchange of Tpm3.1 is not significantly impacted by jasplakinolide, unlike tagged actin. We conclude that tagged Tpm3.1 may be able to undergo exchange in actin filament bundles largely independent of the assembly and turnover of actin.
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Affiliation(s)
- Mark A. Appaduray
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Andrius Masedunskas
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Nicole S. Bryce
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Christine A. Lucas
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Sean C. Warren
- The Kinghorn Cancer Center, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Paul Timpson
- The Kinghorn Cancer Center, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Jeffrey H. Stear
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Peter W. Gunning
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
| | - Edna C. Hardeman
- Cellular and Genetic Medicine Unit, School of Medical Sciences, UNSW Australia, Sydney, New South Wales, Australia
- * E-mail:
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9
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Duan X, Li H, Qiu Z, Joshi BP, Pant A, Smith A, Kurabayashi K, Oldham KR, Wang TD. MEMS-based multiphoton endomicroscope for repetitive imaging of mouse colon. BIOMEDICAL OPTICS EXPRESS 2015; 6:3074-83. [PMID: 26309768 PMCID: PMC4541532 DOI: 10.1364/boe.6.003074] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 07/03/2015] [Accepted: 07/21/2015] [Indexed: 05/08/2023]
Abstract
We demonstrate a handheld multiphoton endomicroscope with 3.4 mm distal diameter that can repetitively image mouse colon in vivo. A 2D resonant MEMS mirror was developed to perform beam scanning in a Lissajous pattern. The instrument has an effective numerical aperture of 0.63, lateral and axial resolution of 2.03 and 9.02 μm, respectively, working distance of 60 μm, and image field-of-view of 300 × 300 μm(2). Hoechst was injected intravenously in mice to stain cell nuclei. We were able to collect histology-like images in vivo at 5 frames/sec, and distinguish between normal and pre-malignant colonic epithelium.
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Affiliation(s)
- Xiyu Duan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Haijun Li
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Bishnu P. Joshi
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Asha Pant
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Arlene Smith
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Katsuo Kurabayashi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kenn R. Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Thomas D. Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
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10
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Sramkova M, Parente L, Wigand T, Aye MP, Shitara A, Weigert R. Polyethylenimine-mediated expression of transgenes in the acinar cells of rats salivary glands in vivo. Front Cell Dev Biol 2015; 2:74. [PMID: 25621283 PMCID: PMC4288386 DOI: 10.3389/fcell.2014.00074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 12/17/2014] [Indexed: 01/04/2023] Open
Abstract
Non viral-mediated transfection of plasmid DNA provides a fast and reliable way to express various transgenes in selected cell populations in live animals. Here, we show an improvement of a previously published method that is based on injecting plasmid DNA into the ductal system of the salivary glands in live rats. Specifically, using complexes between plasmid DNA and polyethyleneimine (PEI) we show that the expression of the transgenes is directed selectively to the salivary acinar cells. PEI does not affect the ability of cells to undergo regulated exocytosis, which was one of the main drawbacks of the previous methods. Moreover PEI does not affect the proper localization and targeting of transfected proteins, as shown for the apical plasma membrane water channel aquaporin 5 (AQP5). Overall, this approach, coupled with the use of intravital microscopy, permits to conduct localization and functional studies under physiological conditions, in a rapid, reliable, and affordable fashion.
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Affiliation(s)
- Monika Sramkova
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
| | - Laura Parente
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
| | - Timothy Wigand
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
| | - Myo-Pale' Aye
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
| | - Akiko Shitara
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
| | - Roberto Weigert
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health Bethesda, MD, USA
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11
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In vivo tissue-wide synchronization of mitochondrial metabolic oscillations. Cell Rep 2014; 9:514-21. [PMID: 25373899 DOI: 10.1016/j.celrep.2014.09.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/09/2014] [Accepted: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
Little is known about the spatiotemporal coordination of mitochondrial metabolism in multicellular organisms in situ. Using intravital microscopy in live animals, we report that mitochondrial metabolism undergoes rapid and periodic oscillations under basal conditions. Notably, mitochondria in vivo behave as a network of functionally coupled oscillators, which maintain a high level of coordination throughout the tissue via the activity of gap junctions. These findings reveal a unique aspect of the relationship between tissue architecture and self-organization of mitochondrial metabolism in vivo.
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12
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Weigert R. Imaging the dynamics of endocytosis in live mammalian tissues. Cold Spring Harb Perspect Biol 2014; 6:a017012. [PMID: 24691962 DOI: 10.1101/cshperspect.a017012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In mammalian cells, endocytosis plays a pivotal role in regulating several basic cellular functions. Up to now, the dynamics and the organization of the endocytic pathways have been primarily investigated in reductionist model systems such as cell and organ cultures. Although these experimental models have been fully successful in unraveling the endocytic machinery at a molecular level, our understanding of the regulation and the role of endocytosis in vivo has been limited. Recently, advancements in intravital microscopy have made it possible to extend imaging in live animals to subcellular structures, thus revealing new aspects of the molecular machineries regulating membrane trafficking that were not previously appreciated in vitro. Here, we focus on the use of intravital microscopy to study endocytosis in vivo, and discuss how this approach will allow addressing two fundamental questions: (1) how endocytic processes are organized in mammalian tissues, and (2) how they contribute to organ physiopathology.
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Affiliation(s)
- Roberto Weigert
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4340
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13
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Dunn KW, Lorenz KS, Salama P, Delp EJ. IMART software for correction of motion artifacts in images collected in intravital microscopy. INTRAVITAL 2014; 3:e28210. [PMID: 26090271 PMCID: PMC4469201 DOI: 10.4161/intv.28210] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Intravital microscopy is a uniquely powerful tool, providing the ability to characterize cell and organ physiology in the natural context of the intact, living animal. With the recent development of high-resolution microscopy techniques such as confocal and multiphoton microscopy, intravital microscopy can now characterize structures at subcellular resolution and capture events at sub-second temporal resolution. However, realizing the potential for high resolution requires remarkable stability in the tissue. Whereas the rigid structure of the skull facilitates high-resolution imaging of the brain, organs of the viscera are free to move with respiration and heartbeat, requiring additional apparatus for immobilization. In our experience, these methods are variably effective, so that many studies are compromised by residual motion artifacts. Here we demonstrate the use of IMART, a software tool for removing motion artifacts from intravital microscopy images collected in time series or in three dimensions.
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Affiliation(s)
- Kenneth W Dunn
- Division of Nephrology; School of Medicine; Indiana University; Indianapolis, IN USA
| | - Kevin S Lorenz
- Video and Image Processing Laboratory; School of Electrical and Computer Engineering; Purdue University; West Lafayette, IN USA
| | - Paul Salama
- Department of Electrical and Computer Engineering; Indiana University; Indianapolis, IN USA
| | - Edward J Delp
- Video and Image Processing Laboratory; School of Electrical and Computer Engineering; Purdue University; West Lafayette, IN USA
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14
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Probing the role of the actin cytoskeleton during regulated exocytosis by intravital microscopy. Methods Mol Biol 2014; 1174:407-21. [PMID: 24947398 DOI: 10.1007/978-1-4939-0944-5_28] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The actin cytoskeleton plays a fundamental role in controlling several steps during regulated exocytosis. Here, we describe a combination of procedures that are aimed at studying the dynamics and the mechanism of the actin cytoskeleton in the salivary glands of live rodents, a model for exocrine secretion. Our approach relies on intravital microscopy, an imaging technique that enables imaging biological events in live animals at a subcellular resolution, and it is complemented by the use of pharmacological agents and indirect immunofluorescence in the salivary tissue.
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15
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Weigert R, Porat-Shliom N, Amornphimoltham P. Imaging cell biology in live animals: ready for prime time. ACTA ACUST UNITED AC 2013; 201:969-79. [PMID: 23798727 PMCID: PMC3691462 DOI: 10.1083/jcb.201212130] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Time-lapse fluorescence microscopy is one of the main tools used to image subcellular structures in living cells. Yet for decades it has been applied primarily to in vitro model systems. Thanks to the most recent advancements in intravital microscopy, this approach has finally been extended to live rodents. This represents a major breakthrough that will provide unprecedented new opportunities to study mammalian cell biology in vivo and has already provided new insight in the fields of neurobiology, immunology, and cancer biology.
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Affiliation(s)
- Roberto Weigert
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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Masedunskas A, Porat-Shliom N, Tora M, Milberg O, Weigert R. Intravital microscopy for imaging subcellular structures in live mice expressing fluorescent proteins. J Vis Exp 2013. [PMID: 24022089 DOI: 10.3791/50558] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Here we describe a procedure to image subcellular structures in live rodents that is based on the use of confocal intravital microscopy. As a model organ, we use the salivary glands of live mice since they provide several advantages. First, they can be easily exposed to enable access to the optics, and stabilized to facilitate the reduction of the motion artifacts due to heartbeat and respiration. This significantly facilitates imaging and tracking small subcellular structures. Second, most of the cell populations of the salivary glands are accessible from the surface of the organ. This permits the use of confocal microscopy that has a higher spatial resolution than other techniques that have been used for in vivo imaging, such as two-photon microscopy. Finally, salivary glands can be easily manipulated pharmacologically and genetically, thus providing a robust system to investigate biological processes at a molecular level. In this study we focus on a protocol designed to follow the kinetics of the exocytosis of secretory granules in acinar cells and the dynamics of the apical plasma membrane where the secretory granules fuse upon stimulation of the beta-adrenergic receptors. Specifically, we used a transgenic mouse that co-expresses cytosolic GFP and a membrane-targeted peptide fused with the fluorescent protein tandem-Tomato. However, the procedures that we used to stabilize and image the salivary glands can be extended to other mouse models and coupled to other approaches to label in vivo cellular components, enabling the visualization of various subcellular structures, such as endosomes, lysosomes, mitochondria, and the actin cytoskeleton.
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Affiliation(s)
- Andrius Masedunskas
- Intracellular Membrane Trafficking Unit, Oral and Pharyngeal Cancer Branch National Institute of Dental and Craniofacial Research, National Institutes of Health
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Intravital Microscopy Reveals Differences in the Kinetics of Endocytic Pathways between Cell Cultures and Live Animals. Cells 2012; 1:1121-32. [PMID: 24710546 PMCID: PMC3901136 DOI: 10.3390/cells1041121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 01/01/2023] Open
Abstract
Intravital microscopy has enabled imaging of the dynamics of subcellular structures in live animals, thus opening the door to investigating membrane trafficking under physiological conditions. Here, we sought to determine whether the architecture and the environment of a fully developed tissue influences the dynamics of endocytic processes. To this aim, we imaged endocytosis in the stromal cells of rat salivary glands both in situ and after they were isolated and cultured on a solid surface. We found that the internalization of transferrin and dextran, two molecules that traffic via distinct mechanisms, is substantially altered in cultured cells, supporting the idea that the three dimensional organization of the tissue and the cues generated by the surrounding environment strongly affect membrane trafficking events.
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Masedunskas A, Milberg O, Porat-Shliom N, Sramkova M, Wigand T, Amornphimoltham P, Weigert R. Intravital microscopy: a practical guide on imaging intracellular structures in live animals. BIOARCHITECTURE 2012; 2:143-57. [PMID: 22992750 PMCID: PMC3696059 DOI: 10.4161/bioa.21758] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 08/05/2012] [Accepted: 08/07/2012] [Indexed: 01/05/2023]
Abstract
Intravital microscopy is an extremely powerful tool that enables imaging several biological processes in live animals. Recently, the ability to image subcellular structures in several organs combined with the development of sophisticated genetic tools has made possible extending this approach to investigate several aspects of cell biology. Here we provide a general overview of intravital microscopy with the goal of highlighting its potential and challenges. Specifically, this review is geared toward researchers that are new to intravital microscopy and focuses on practical aspects of carrying out imaging in live animals. Here we share the know-how that comes from first-hand experience, including topics such as choosing the right imaging platform and modality, surgery and stabilization techniques, anesthesia and temperature control. Moreover, we highlight some of the approaches that facilitate subcellular imaging in live animals by providing numerous examples of imaging selected organelles and the actin cytoskeleton in multiple organs.
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Affiliation(s)
- Andrius Masedunskas
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
- Department of Biology; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
| | - Oleg Milberg
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
- Department of Chemical and Biochemical Engineering; Rutgers University; Piscataway, NJ USA
- Department of Biomedical Engineering; Rutgers University; Piscataway, NJ USA
| | - Natalie Porat-Shliom
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Monika Sramkova
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Tim Wigand
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Panomwat Amornphimoltham
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
| | - Roberto Weigert
- Intracellular Membrane Trafficking Unit; Oral and Pharyngeal Cancer Branch; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda, MD USA
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