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Bodenschatz JFE, Ajmail K, Skamrahl M, Vache M, Gottwald J, Nehls S, Janshoff A. Epithelial cells sacrifice excess area to preserve fluidity in response to external mechanical stress. Commun Biol 2022; 5:855. [PMID: 35995827 PMCID: PMC9395404 DOI: 10.1038/s42003-022-03809-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/04/2022] [Indexed: 11/24/2022] Open
Abstract
Viscoelastic properties of epithelial cells subject to shape changes were monitored by indentation-retraction/relaxation experiments. MDCK II cells cultured on extensible polydimethylsiloxane substrates were laterally stretched and, in response, displayed increased cortex contractility and loss of excess surface area. Thereby, the cells preserve their fluidity but inevitably become stiffer. We found similar behavior in demixed cell monolayers of ZO-1/2 double knock down (dKD) cells, cells exposed to different temperatures and after removal of cholesterol from the plasma membrane. Conversely, the mechanical response of single cells adhered onto differently sized patches displays no visible rheological change. Sacrificing excess surface area allows the cells to respond to mechanical challenges without losing their ability to flow. They gain a new degree of freedom that permits resolving the interdependence of fluidity β on stiffness [Formula: see text]. We also propose a model that permits to tell apart contributions from excess membrane area and excess cell surface area.
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Affiliation(s)
- Jonathan F E Bodenschatz
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Karim Ajmail
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Mark Skamrahl
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Marian Vache
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Jannis Gottwald
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Stefan Nehls
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany
| | - Andreas Janshoff
- Georg-August Universität Göttingen, Institute of Physical Chemistry, Tammannstr. 6, 37077, Göttingen, Germany.
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2
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Wu D, Chapela PJ, Barrows CML, Harrington DA, Carson DD, Witt RL, Mohyuddin NG, Pradhan-Bhatt S, Farach-Carson MC. MUC1 and Polarity Markers INADL and SCRIB Identify Salivary Ductal Cells. J Dent Res 2022; 101:983-991. [PMID: 35259994 DOI: 10.1177/00220345221076122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Current treatments for xerostomia/dry mouth are palliative and largely ineffective. A permanent clinical resolution is being developed to correct hyposalivation using implanted hydrogel-encapsulated salivary human stem/progenitor cells (hS/PCs) to restore functional salivary components and increase salivary flow. Pluripotent epithelial cell populations derived from hS/PCs, representing a basal stem cell population in tissue, can differentiate along either secretory acinar or fluid-transporting ductal lineages. To develop tissue-engineered salivary gland replacement tissues, it is critical to reliably identify cells in tissue and as they enter these alternative lineages. The secreted protein α-amylase, the transcription factor MIST1, and aquaporin-5 are typical markers for acinar cells, and K19 is the classical ductal marker in salivary tissue. We found that early ductal progenitors derived from hS/PCs do not express K19, and thus earlier markers were needed to distinguish these cells from acinar progenitors. Salivary ductal cells express distinct polarity complex proteins that we hypothesized could serve as lineage biomarkers to distinguish ductal cells from acinar cells in differentiating hS/PC populations. Based on our studies of primary salivary tissue, both parotid and submandibular glands, and differentiating hS/PCs, we conclude that the apical marker MUC1 along with the polarity markers INADL/PATJ and SCRIB reliably can identify ductal cells in salivary glands and in ductal progenitor populations of hS/PCs being used for salivary tissue engineering. Other markers of epithelial maturation, including E-cadherin, ZO-1, and partition complex component PAR3, are present in both ductal and acinar cells, where they can serve as general markers of differentiation but not lineage markers.
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Affiliation(s)
- D Wu
- Department of Diagnostic and Biomedical Sciences, Center for Craniofacial Research, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA
| | - P J Chapela
- Department of BioSciences, Rice University, Houston, TX, USA
| | - C M L Barrows
- Department of Diagnostic and Biomedical Sciences, Center for Craniofacial Research, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA
| | - D A Harrington
- Department of Diagnostic and Biomedical Sciences, Center for Craniofacial Research, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA.,Department of BioSciences, Rice University, Houston, TX, USA
| | - D D Carson
- Department of BioSciences, Rice University, Houston, TX, USA
| | - R L Witt
- Department of Biological Sciences, Center for Translational Cancer Biology, University of Delaware, Newark, DE, USA.,Helen F. Graham Cancer Center, Christiana Care Health Systems, Newark, DE, USA
| | - N G Mohyuddin
- Department of Clinical Otolaryngology, Houston Methodist Hospital, Houston, TX, USA
| | - S Pradhan-Bhatt
- Department of Biological Sciences, Center for Translational Cancer Biology, University of Delaware, Newark, DE, USA.,Helen F. Graham Cancer Center, Christiana Care Health Systems, Newark, DE, USA
| | - M C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, Center for Craniofacial Research, University of Texas Health Science Center at Houston School of Dentistry, Houston, TX, USA.,Department of Bioengineering, Rice University, Houston, TX, USA.,Department of BioSciences, Rice University, Houston, TX, USA
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3
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Dynamic polyhedral actomyosin lattices remodel micron-scale curved membranes during exocytosis in live mice. Nat Cell Biol 2019; 21:933-939. [PMID: 31358965 DOI: 10.1038/s41556-019-0365-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/25/2019] [Indexed: 01/10/2023]
Abstract
Actomyosin networks, the cell's major force production machineries, remodel cellular membranes during myriad dynamic processes1,2 by assembling into various architectures with distinct force generation properties3,4. While linear and branched actomyosin architectures are well characterized in cell-culture and cell-free systems3, it is not known how actin and myosin networks form and function to remodel membranes in complex three-dimensional mammalian tissues. Here, we use four-dimensional spinning-disc confocal microscopy with image deconvolution to acquire macromolecular-scale detail of dynamic actomyosin networks in exocrine glands of live mice. We address how actin and myosin organize around large membrane-bound secretory vesicles and generate the forces required to complete exocytosis5-7. We find that actin and non-muscle myosin II (NMII) assemble into previously undescribed polyhedral-like lattices around the vesicle membrane. The NMII lattice comprises bipolar minifilaments8-10 as well as non-canonical three-legged configurations. Using photobleaching and pharmacological perturbations in vivo, we show that actomyosin contractility and actin polymerization together push on the underlying vesicle membrane to overcome the energy barrier and complete exocytosis7. Our imaging approach thus unveils a force-generating actomyosin lattice that regulates secretion in the exocrine organs of live animals.
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4
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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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5
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Ebrahim S, Liu J, Weigert R. The Actomyosin Cytoskeleton Drives Micron-Scale Membrane Remodeling In Vivo Via the Generation of Mechanical Forces to Balance Membrane Tension Gradients. Bioessays 2018; 40:e1800032. [PMID: 30080263 DOI: 10.1002/bies.201800032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/29/2018] [Indexed: 12/31/2022]
Abstract
The remodeling of biological membranes is crucial for a vast number of cellular activities and is an inherently multiscale process in both time and space. Seminal work has provided important insights into nanometer-scale membrane deformations, and highlighted the remarkable variation and complexity in the underlying molecular machineries and mechanisms. However, how membranes are remodeled at the micron-scale, particularly in vivo, remains poorly understood. Here, we discuss how using regulated exocytosis of large (1.5-2.0 μm) membrane-bound secretory granules in the salivary gland of live mice as a model system, has provided evidence for the importance of the actomyosin cytoskeleton in micron-scale membrane remodeling in physiological conditions. We highlight some of these advances, and present mechanistic hypotheses for how the various biochemical and biophysical properties of distinct actomyosin networks may drive this process.
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Affiliation(s)
- Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.,National Institutes of Health, Bethesda, MD 20892, USA
| | - Jian Liu
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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6
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Milberg O, Shitara A, Ebrahim S, Masedunskas A, Tora M, Tran DT, Chen Y, Conti MA, Adelstein RS, Ten Hagen KG, Weigert R. Concerted actions of distinct nonmuscle myosin II isoforms drive intracellular membrane remodeling in live animals. J Cell Biol 2017; 216:1925-1936. [PMID: 28600434 PMCID: PMC5496622 DOI: 10.1083/jcb.201612126] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/02/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022] Open
Abstract
Membrane remodeling plays a fundamental role during a variety of biological events. However, the dynamics and the molecular mechanisms regulating this process within cells in mammalian tissues in situ remain largely unknown. In this study, we use intravital subcellular microscopy in live mice to study the role of the actomyosin cytoskeleton in driving the remodeling of membranes of large secretory granules, which are integrated into the plasma membrane during regulated exocytosis. We show that two isoforms of nonmuscle myosin II, NMIIA and NMIIB, control distinct steps of the integration process. Furthermore, we find that F-actin is not essential for the recruitment of NMII to the secretory granules but plays a key role in the assembly and activation of NMII into contractile filaments. Our data support a dual role for the actomyosin cytoskeleton in providing the mechanical forces required to remodel the lipid bilayer and serving as a scaffold to recruit key regulatory molecules.
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Affiliation(s)
- Oleg Milberg
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Akiko Shitara
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD.,Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Seham Ebrahim
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Andrius Masedunskas
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD.,School of Medical Sciences, University of New South Wales, Sidney, Australia
| | - Muhibullah Tora
- Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
| | - Duy T Tran
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Yun Chen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Mary Anne Conti
- Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Robert S Adelstein
- Laboratory of Molecular Cardiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Kelly G Ten Hagen
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD .,Intracellular Membrane Trafficking Section, National Institutes of Health, Bethesda, MD
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7
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Gluck C, Min S, Oyelakin A, Smalley K, Sinha S, Romano RA. RNA-seq based transcriptomic map reveals new insights into mouse salivary gland development and maturation. BMC Genomics 2016; 17:923. [PMID: 27852218 PMCID: PMC5112738 DOI: 10.1186/s12864-016-3228-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 10/29/2016] [Indexed: 11/16/2022] Open
Abstract
Background Mouse models have served a valuable role in deciphering various facets of Salivary Gland (SG) biology, from normal developmental programs to diseased states. To facilitate such studies, gene expression profiling maps have been generated for various stages of SG organogenesis. However these prior studies fall short of capturing the transcriptional complexity due to the limited scope of gene-centric microarray-based technology. Compared to microarray, RNA-sequencing (RNA-seq) offers unbiased detection of novel transcripts, broader dynamic range and high specificity and sensitivity for detection of genes, transcripts, and differential gene expression. Although RNA-seq data, particularly under the auspices of the ENCODE project, have covered a large number of biological specimens, studies on the SG have been lacking. Results To better appreciate the wide spectrum of gene expression profiles, we isolated RNA from mouse submandibular salivary glands at different embryonic and adult stages. In parallel, we processed RNA-seq data for 24 organs and tissues obtained from the mouse ENCODE consortium and calculated the average gene expression values. To identify molecular players and pathways likely to be relevant for SG biology, we performed functional gene enrichment analysis, network construction and hierarchal clustering of the RNA-seq datasets obtained from different stages of SG development and maturation, and other mouse organs and tissues. Our bioinformatics-based data analysis not only reaffirmed known modulators of SG morphogenesis but revealed novel transcription factors and signaling pathways unique to mouse SG biology and function. Finally we demonstrated that the unique SG gene signature obtained from our mouse studies is also well conserved and can demarcate features of the human SG transcriptome that is different from other tissues. Conclusions Our RNA-seq based Atlas has revealed a high-resolution cartographic view of the dynamic transcriptomic landscape of the mouse SG at various stages. These RNA-seq datasets will complement pre-existing microarray based datasets, including the Salivary Gland Molecular Anatomy Project by offering a broader systems-biology based perspective rather than the classical gene-centric view. Ultimately such resources will be valuable in providing a useful toolkit to better understand how the diverse cell population of the SG are organized and controlled during development and differentiation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3228-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christian Gluck
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, 14203, USA
| | - Sangwon Min
- Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, 14214, USA
| | - Akinsola Oyelakin
- Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, 14214, USA
| | - Kirsten Smalley
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, 14203, USA
| | - Satrajit Sinha
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, 14203, USA.
| | - Rose-Anne Romano
- Department of Oral Biology, School of Dental Medicine, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, 14214, USA.
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8
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Shitara A, Weigert R. Imaging membrane remodeling during regulated exocytosis in live mice. Exp Cell Res 2015; 337:219-25. [PMID: 26160452 DOI: 10.1016/j.yexcr.2015.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/28/2015] [Indexed: 10/23/2022]
Abstract
In this mini-review we focus on the use of time-lapse light microscopy to study membrane remodeling during protein secretion in live animals. In particular, we highlight how subcellular intravital microscopy has enabled imaging the dynamics of both individual secretory vesicles and the plasma membrane, during different steps in the exocytic process. This powerful approach has provided us with the unique opportunity to unravel the role of the actin cytoskeleton in regulating this process under physiological conditions, and to overcome the shortcomings of more reductionist model systems.
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Affiliation(s)
- Akiko Shitara
- Intracellular Membrane Trafficking Section, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr. 303A, Bethesda, MD 20892-4340, United States
| | - Roberto Weigert
- Intracellular Membrane Trafficking Section, Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr. 303A, Bethesda, MD 20892-4340, United States.
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9
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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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10
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Masedunskas A, Appaduray M, Hardeman EC, Gunning PW. What makes a model system great? INTRAVITAL 2014. [DOI: 10.4161/intv.26287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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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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12
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Gunning P. BioArchitecture: the organization and regulation of biological space. BIOARCHITECTURE 2012; 2:200-3. [PMID: 23267413 PMCID: PMC3527313 DOI: 10.4161/bioa.22726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BioArchitecture is a term used to describe the organization and regulation of biological space. It applies to the principles which govern the structure of molecules, polymers and mutiprotein complexes, organelles, membranes and their organization in the cytoplasm and the nucleus. It also covers the integration of cells into their three dimensional environment at the level of cell-matrix, cell-cell interactions, integration into tissue/organ structure and function and finally into the structure of the organism. This review will highlight studies at all these levels which are providing a new way to think about the relationship between the organization of biological space and the function of biological systems.
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Affiliation(s)
- Peter Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia.
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13
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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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14
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Multiple roles for the actin cytoskeleton during regulated exocytosis. Cell Mol Life Sci 2012; 70:2099-121. [PMID: 22986507 DOI: 10.1007/s00018-012-1156-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/28/2012] [Accepted: 08/30/2012] [Indexed: 01/01/2023]
Abstract
Regulated exocytosis is the main mechanism utilized by specialized secretory cells to deliver molecules to the cell surface by virtue of membranous containers (i.e., secretory vesicles). The process involves a series of highly coordinated and sequential steps, which include the biogenesis of the vesicles, their delivery to the cell periphery, their fusion with the plasma membrane, and the release of their content into the extracellular space. Each of these steps is regulated by the actin cytoskeleton. In this review, we summarize the current knowledge regarding the involvement of actin and its associated molecules during each of the exocytic steps in vertebrates, and suggest that the overall role of the actin cytoskeleton during regulated exocytosis is linked to the architecture and the physiology of the secretory cells under examination. Specifically, in neurons, neuroendocrine, endocrine, and hematopoietic cells, which contain small secretory vesicles that undergo rapid exocytosis (on the order of milliseconds), the actin cytoskeleton plays a role in pre-fusion events, where it acts primarily as a functional barrier and facilitates docking. In exocrine and other secretory cells, which contain large secretory vesicles that undergo slow exocytosis (seconds to minutes), the actin cytoskeleton plays a role in post-fusion events, where it regulates the dynamics of the fusion pore, facilitates the integration of the vesicles into the plasma membrane, provides structural support, and promotes the expulsion of large cargo molecules.
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15
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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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Masedunskas A, Porat-Shliom N, Weigert R. Regulated exocytosis: novel insights from intravital microscopy. Traffic 2012; 13:627-34. [PMID: 22243493 DOI: 10.1111/j.1600-0854.2012.01328.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/11/2012] [Accepted: 01/13/2012] [Indexed: 12/20/2022]
Abstract
Regulated exocytosis is a fundamental process that every secretory cell uses to deliver molecules to the cell surface and the extracellular space by virtue of membranous carriers. This process has been extensively studied using various approaches such as biochemistry, electrophysiology and electron microscopy. However, recent developments in time-lapse light microscopy have made possible imaging individual exocytic events, hence, advancing our understanding of this process at a molecular level. In this review, we focus on intravital microscopy (IVM), a light microscopy-based approach that enables imaging subcellular structures in live animals, and discuss its recent application to study regulated exocytosis. IVM has revealed differences in regulation and modality of regulated exocytosis between in vitro and in vivo model systems, unraveled novel aspects of this process that can be appreciated only in in vivo settings and provided valuable and novel information on its molecular machinery. In conclusion, we make the case for IVM being a mature technique that can be used to investigate the molecular machinery of several intracellular events under physiological conditions.
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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, 30 Convent Dr. 303A, Bethesda, MD 20892-4340, USA
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