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Abstract
Real-time imaging of regulated exocytosis in secreting organs can provide unprecedented temporal and spatial detail. Here, we highlight recent advances in 3D time-lapse imaging in Drosophila salivary glands at single-granule resolution. Using fluorescently labeled proteins expressed in the fly, it is now possible to image the dynamics of vesicle biogenesis and the cytoskeletal factors involved in secretion. 3D imaging over time allows one to visualize and define the temporal sequence of events, including clearance of cortical actin, fusion pore formation, mixing of the vesicular and plasma membranes and recruitment of components of the cytoskeleton. We will also discuss the genetic tools available in the fly that allow one to interrogate the essential factors involved in secretory vesicle formation, cargo secretion and the ultimate integration of the vesicular and plasma membranes. We argue that the combination of high-resolution real-time imaging and powerful genetics provides a platform to investigate the role of any factor in regulated secretion.
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Affiliation(s)
- Duy T Tran
- Section on Biological Chemistry, NIDCR, National Institutes of Health, 30 Convent Drive, Bethesda, MD 20892, USA
| | - Kelly G Ten Hagen
- Developmental Glycobiology Section, NIDCR, National Institutes of Health, 30 Convent Drive, Bethesda, MD 20892, USA
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52
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Cong X, Zhang Y, He QH, Wei T, Zhang XM, Zhang JZ, Xiang RL, Yu GY, Wu LL. Endothelial Tight Junctions Are Opened in Cholinergic-Evoked Salivation In Vivo. J Dent Res 2017; 96:562-570. [PMID: 28118553 DOI: 10.1177/0022034516685048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Blood vessels provide the original supplies for the formation of primary saliva, which is regulated by the tight junctions (TJs) between endothelial cells. Previous studies have shown that blood flow increases with vasodilatation during cholinergic-evoked salivation. However, changes in vascular paracellular permeability and the role of endothelial TJs in salivation are unknown. Here, we established an in vivo paracellular permeability detection system and observed that the endothelial TJs were permeable to 4-kDa fluorescein isothiocyanate (FITC)-dextran while impermeable to 40- and 70-kDa FITC-dextran under an unstimulated condition in mouse submandibular glands (SMGs). Pilocarpine increased the flux of 4- and 40-kDa FITC-dextran out of blood vessels but did not affect 70-kDa FITC-dextran. Claudin 5, a TJ protein specifically localized in salivary endothelial cells, was redistributed from the apicolateral membranes to the lateral and basolateral membranes and cytoplasm in cholinergic-stimulated mouse SMGs and freshly cultured human SMG tissues. In the transplanted SMGs from epiphora patients, we found that claudin 5 was present in the basolateral membranes and cytoplasm, instead of the apical region in control SMGs. Moreover, the level of phospho-myosin light chain 2 increased within the blood vessels of the pilocarpine-stimulated mouse SMGs and transplanted human SMGs, while the downstream molecule F-actin was reorganized in the endothelial cells of the transplanted human SMGs. Taken together, our findings provide direct visual evidence that the opening of endothelial TJs and the redistribution of claudin 5 are essential events contributing to cholinergic-evoked salivation, thus enriching our understanding of the secretory mechanisms that link blood flow to primary saliva formation by regulating the endothelial paracellular permeability.
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Affiliation(s)
- X Cong
- 1 Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, P.R. China
| | - Y Zhang
- 1 Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, P.R. China
| | - Q H He
- 2 Center of Medical and Health Analysis, Peking University Health Science Center, Beijing, P.R. China
| | - T Wei
- 3 Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, P.R. China
| | - X M Zhang
- 3 Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, P.R. China
| | - J Z Zhang
- 1 Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, P.R. China
| | - R L Xiang
- 1 Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, P.R. China
| | - G Y Yu
- 3 Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, P.R. China
| | - L L Wu
- 1 Center for Salivary Gland Diseases of Peking University School and Hospital of Stomatology, Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, P.R. China
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53
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Abstract
Over the past decade, major advances in imaging techniques have enhanced our understanding of Plasmodium spp. parasites and their interplay with mammalian hosts and mosquito vectors. Cryoelectron tomography, cryo-X-ray tomography and super-resolution microscopy have shifted paradigms of sporozoite and gametocyte structure, the process of erythrocyte invasion by merozoites, and the architecture of Maurer's clefts. Intravital time-lapse imaging has been revolutionary for our understanding of pre-erythrocytic stages of rodent Plasmodium parasites. Furthermore, high-speed imaging has revealed the link between sporozoite structure and motility, and improvements in time-lapse microscopy have enabled imaging of the entire Plasmodium falciparum erythrocytic cycle and the complete Plasmodium berghei pre-erythrocytic stages for the first time. In this Review, we discuss the contribution of key imaging tools to these and other discoveries in the malaria field over the past 10 years.
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54
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Wang Z. Imaging Nanotherapeutics in Inflamed Vasculature by Intravital Microscopy. Am J Cancer Res 2016; 6:2431-2438. [PMID: 27877245 PMCID: PMC5118605 DOI: 10.7150/thno.16307] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/04/2016] [Indexed: 12/21/2022] Open
Abstract
Intravital microscopy (IVM) is the application of light microscopy to real time study biology of live animal tissues in intact and physiological conditions with the high spatial and temporal resolution. Advances in imaging systems, genetic animal models and imaging probes, IVM has offered quantitative and dynamic insight into cell biology, immunology, neurobiology and cancer. In this review, we will focus on the targeting of nanotherapeutics to inflamed vasculature. We will introduce the basic concept and principle of IVM and demonstrate that IVM is a powerful tool used to quantitatively determine the molecular mechanisms of interactions between nanotherapeutics and neutrophils or endothelium in living mice. In the future, it is needed to develop new imaging systems and novel imaging contrast agents to better understand molecular mechanisms of tissue processing of nanotherapeutics in vivo.
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55
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Perazzo J, Lopes-Ferreira M, Sá Santos S, Serrano I, Pinto A, Lima C, Bardaji E, Tavares I, Heras M, Conceição K, Castanho MARB. Endothelium-Mediated Action of Analogues of the Endogenous Neuropeptide Kyotorphin (Tyrosil-Arginine): Mechanistic Insights from Permeation and Effects on Microcirculation. ACS Chem Neurosci 2016; 7:1130-40. [PMID: 27244291 DOI: 10.1021/acschemneuro.6b00099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Kyotorphin (KTP) is an endogenous peptide with analgesic properties when administered into the central nervous system (CNS). Its amidated form (l-Tyr-l-Arg-NH2; KTP-NH2) has improved analgesic efficacy after systemic administration, suggesting blood-brain barrier (BBB) crossing. KTP-NH2 also has anti-inflammatory action impacting on microcirculation. In this work, selected derivatives of KTP-NH2 were synthesized to improve lipophilicity and resistance to enzymatic degradation while introducing only minor changes in the chemical structure: N-terminal methylation and/or use of d amino acid residues. Intravital microscopy data show that KTP-NH2 having a d-Tyr residue, KTP-NH2-DL, efficiently decreases the number of leukocyte rolling in a murine model of inflammation induced by bacterial lipopolysaccharide (LPS): down to 46% after 30 min with 96 μM KTP-NH2-DL. The same molecule has lower ability to permeate membranes (relative permeability of 0.38) and no significant activity in a behavioral test which evaluates thermal nociception (hot-plate test). On the contrary, methylated isomers at 96 μM increase leukocyte rolling up to nearly 5-fold after 30 min, suggesting a proinflammatory activity. They have maximal ability to permeate membranes (relative permeability of 0.8) and induce long-lasting antinociception.
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Affiliation(s)
- Juliana Perazzo
- Instituto de Medicina
Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Mônica Lopes-Ferreira
- Unidade
de Imunorregulação, Laboratório Especial de Toxinologia
Aplicada, Instituto Butantan, Av. Vital Brasil, 1500 São Paulo, Brazil
| | - Sónia Sá Santos
- Instituto de Medicina
Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Isa Serrano
- Instituto de Medicina
Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Antónia Pinto
- Instituto de Medicina
Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Carla Lima
- Unidade
de Imunorregulação, Laboratório Especial de Toxinologia
Aplicada, Instituto Butantan, Av. Vital Brasil, 1500 São Paulo, Brazil
| | - Eduard Bardaji
- Laboratori
d’Innovació en processos i Productes de Síntesi
Orgànica (LIPPSO), Department de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain
| | - Isaura Tavares
- Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 4150-180 Porto, Portugal
- i3S
- Instituto de Inovação e Investigação
em Saúde, and Departamento de Biologia Experimental, Faculdade
de Medicina, Universidade do Porto, 4099-002 Porto, Portugal
| | - Montserrat Heras
- Laboratori
d’Innovació en processos i Productes de Síntesi
Orgànica (LIPPSO), Department de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain
| | - Katia Conceição
- Departamento
de Ciência e Tecnologia, Universidade Federal de São Paulo, UNIFESP, Rua Talim, 330, 04021-001 São José dos Campos, Brazil
| | - Miguel A. R. B. Castanho
- Instituto de Medicina
Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal
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56
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Schießl IM, Castrop H. Deep insights: intravital imaging with two-photon microscopy. Pflugers Arch 2016; 468:1505-16. [PMID: 27352273 DOI: 10.1007/s00424-016-1832-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 01/03/2023]
Abstract
Intravital multiphoton microscopy is widely used to assess the structure and function of organs in live animals. Although different tissues vary in their accessibility for intravital multiphoton imaging, considerable progress has been made in the imaging quality of all tissues due to substantial technical improvements in the relevant imaging components, such as optics, excitation laser, detectors, and signal analysis software. In this review, we provide an overview of the technical background of intravital multiphoton microscopy. Then, we note a few seminal findings that were made through the use of multiphoton microscopy. Finally, we address the technical limitations of the method and provide an outlook for how these limitations may be overcome through future technical developments.
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Affiliation(s)
- Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany.
| | - Hayo Castrop
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany
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57
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Trichobilharzia regenti (Schistosomatidae): 3D imaging techniques in characterization of larval migration through the CNS of vertebrates. Micron 2016; 83:62-71. [DOI: 10.1016/j.micron.2016.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 01/29/2016] [Accepted: 01/29/2016] [Indexed: 01/12/2023]
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58
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Greathouse KM, Palladino SP, Dong C, Helton ES, Ubogu EE. Modeling leukocyte trafficking at the human blood-nerve barrier in vitro and in vivo geared towards targeted molecular therapies for peripheral neuroinflammation. J Neuroinflammation 2016; 13:3. [PMID: 26732309 PMCID: PMC4702318 DOI: 10.1186/s12974-015-0469-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 12/24/2015] [Indexed: 12/19/2022] Open
Abstract
Peripheral neuroinflammation is characterized by hematogenous mononuclear leukocyte infiltration into peripheral nerves. Despite significant clinical knowledge, advancements in molecular biology and progress in developing specific drugs for inflammatory disorders such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis, there are currently no specific therapies that modulate pathogenic peripheral nerve inflammation. Modeling leukocyte trafficking at the blood-nerve barrier using a reliable human in vitro model and potential intravital microscopy techniques in representative animal models guided by human observational data should facilitate the targeted modulation of the complex inflammatory cascade needed to develop safe and efficacious therapeutics for immune-mediated neuropathies and chronic neuropathic pain.
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Affiliation(s)
- Kelsey M Greathouse
- Department of Neurology, Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, The University of Alabama at Birmingham, 1825 University Boulevard, Room 1131, Birmingham, AL, 35294-0017, USA.
| | - Steven P Palladino
- Department of Neurology, Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, The University of Alabama at Birmingham, 1825 University Boulevard, Room 1131, Birmingham, AL, 35294-0017, USA.
| | - Chaoling Dong
- Department of Neurology, Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, The University of Alabama at Birmingham, 1825 University Boulevard, Room 1131, Birmingham, AL, 35294-0017, USA.
| | - Eric S Helton
- Department of Neurology, Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, The University of Alabama at Birmingham, 1825 University Boulevard, Room 1131, Birmingham, AL, 35294-0017, USA.
| | - Eroboghene E Ubogu
- Department of Neurology, Neuromuscular Immunopathology Research Laboratory, Division of Neuromuscular Disease, The University of Alabama at Birmingham, 1825 University Boulevard, Room 1131, Birmingham, AL, 35294-0017, USA.
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59
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Babes L, Kubes P. Visualizing the Tumor Microenvironment of Liver Metastasis by Spinning Disk Confocal Microscopy. Methods Mol Biol 2016; 1458:203-15. [PMID: 27581024 DOI: 10.1007/978-1-4939-3801-8_15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Intravital microscopy has evolved into an invaluable technique to study the complexity of tumors by visualizing individual cells in live organisms. Here, we describe a method for employing intravital spinning disk confocal microscopy to picture high-resolution tumor-stroma interactions in real time. We depict in detail the surgical procedures to image various tumor microenvironments and different cellular components in the liver.
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Affiliation(s)
- Liane Babes
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Paul Kubes
- Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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60
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Follain G, Mercier L, Osmani N, Harlepp S, Goetz JG. Seeing is believing: multi-scale spatio-temporal imaging towards in vivo cell biology. J Cell Sci 2016; 130:23-38. [DOI: 10.1242/jcs.189001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
Life is driven by a set of biological events that are naturally dynamic and tightly orchestrated from the single molecule to entire organisms. Although biochemistry and molecular biology have been essential in deciphering signaling at a cellular and organismal level, biological imaging has been instrumental for unraveling life processes across multiple scales. Imaging methods have considerably improved over the past decades and now allow to grasp the inner workings of proteins, organelles, cells, organs and whole organisms. Not only do they allow us to visualize these events in their most-relevant context but also to accurately quantify underlying biomechanical features and, so, provide essential information for their understanding. In this Commentary, we review a palette of imaging (and biophysical) methods that are available to the scientific community for elucidating a wide array of biological events. We cover the most-recent developments in intravital imaging, light-sheet microscopy, super-resolution imaging, and correlative light and electron microscopy. In addition, we illustrate how these technologies have led to important insights in cell biology, from the molecular to the whole-organism resolution. Altogether, this review offers a snapshot of the current and state-of-the-art imaging methods that will contribute to the understanding of life and disease.
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Affiliation(s)
- Gautier Follain
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Luc Mercier
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Naël Osmani
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Sébastien Harlepp
- Université de Strasbourg, Strasbourg F-67000, France
- DON: Optique ultrarapide et nanophotonique, IPCMS UMR7504, Strasbourg 67000, France
- LabEx NIE, Université de Strasbourg, Strasbourg F-67000, France
| | - Jacky G. Goetz
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
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61
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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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62
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Nezu A, Morita T, Tanimura A. In vitro and in vivo imaging of intracellular Ca2+ responses in salivary gland cells. J Oral Biosci 2015. [DOI: 10.1016/j.job.2015.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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63
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Chen X, Kezic JM, Forrester JV, Goldberg GL, Wicks IP, Bernard CC, McMenamin PG. In vivo multi-modal imaging of experimental autoimmune uveoretinitis in transgenic reporter mice reveals the dynamic nature of inflammatory changes during disease progression. J Neuroinflammation 2015; 12:17. [PMID: 25623142 PMCID: PMC4336748 DOI: 10.1186/s12974-015-0235-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/05/2015] [Indexed: 12/22/2022] Open
Abstract
Background Experimental autoimmune uveoretinitis (EAU) is a widely used experimental animal model of human endogenous posterior uveoretinitis. In the present study, we performed in vivo imaging of the retina in transgenic reporter mice to investigate dynamic changes in exogenous inflammatory cells and endogenous immune cells during the disease process. Methods Transgenic mice (C57Bl/6 J Cx3cr1GFP/+, C57Bl/6 N CD11c-eYFP, and C57Bl/6 J LysM-eGFP) were used to visualize the dynamic changes of myeloid-derived cells, putative dendritic cells and neutrophils during EAU. Transgenic mice were monitored with multi-modal fundus imaging camera over five time points following disease induction with the retinal auto-antigen, interphotoreceptor retinoid binding protein (IRBP1–20). Disease severity was quantified with both clinical and histopathological grading. Results In the normal C57Bl/6 J Cx3cr1GFP/+ mouse Cx3cr1-expressing microglia were evenly distributed in the retina. In C57Bl/6 N CD11c-eYFP mice clusters of CD11c-expressing cells were noted in the retina and in C57Bl/6 J LysM-eGFP mice very low numbers of LysM-expressing neutrophils were observed in the fundus. Following immunization with IRBP1–20, fundus examination revealed accumulations of Cx3cr1-GFP+ myeloid cells, CD11c-eYFP+ cells and LysM-eGFP+ myelomonocytic cells around the optic nerve head and along retinal vessels as early as day 14 post-immunization. CD11c-eYFP+ cells appear to resolve marginally earlier (day 21 post-immunization) than Cx3cr1-GFP+ and LysM-eGFP+ cells. The clinical grading of EAU in transgenic mice correlated closely with histopathological grading. Conclusions These results illustrate that in vivo fundus imaging of transgenic reporter mice allows direct visualization of various exogenously and endogenously derived leukocyte types during EAU progression. This approach acts as a valuable adjunct to other methods of studying the clinical course of EAU. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0235-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiangting Chen
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
| | - Jelena M Kezic
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
| | - John V Forrester
- Section of Immunology and Infection, Division of Applied Medicine, School of Medicine and Dentistry, Institute of Medical Science, Foresterhill, University of Aberdeen, Scotland, UK. .,Ocular Immunology Program, Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia. .,Centre for Experimental Immunology, Lions Eye Institute, Nedlands, Crawley, Western Australia, Australia.
| | - Gabrielle L Goldberg
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
| | - Ian P Wicks
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
| | - Claude C Bernard
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia.
| | - Paul G McMenamin
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
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64
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Abstract
To demonstrate effects of aging visually requires a robust technique that can reproducibly detect small differences in efficiency or kinetics between groups. Investigators of aging will greatly appreciate the benefits of Amnis ImageStream technology ( www.amnis.com/), which combines quantitative flow cytometry with simultaneous high-resolution digital imaging. Imagestream is quantitative, reproducible, feasible with limited samples, and it facilitates in-depth examination of cellular mechanisms between cohorts of samples.
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Affiliation(s)
- Feng Qian
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, 300 Cedar Street/TAC S413, New Haven, CT, 06520, USA
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Ruth R Montgomery
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, 300 Cedar Street/TAC S413, New Haven, CT, 06520, USA.
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65
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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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66
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Sandoval RM, Wang E, Molitoris BA. Finding the bottom and using it: Offsets and sensitivity in the detection of low intensity values in vivo with 2-photon microscopy. INTRAVITAL 2014; 2. [PMID: 25313346 DOI: 10.4161/intv.23674] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Maximizing 2-photon parameters used in acquiring images for quantitative intravital microscopy, especially when high sensitivity is required, remains an open area of investigation. Here we present data on correctly setting the black level of the photomultiplier tube amplifier by adjusting the offset to allow for accurate quantitation of low intensity processes. When the black level is set too high some low intensity pixel values become zero and a nonlinear degradation in sensitivity occurs rendering otherwise quantifiable low intensity values virtually undetectable. Initial studies using a series of increasing offsets for a sequence of concentrations of fluorescent albumin in vitro revealed a loss of sensitivity for higher offsets at lower albumin concentrations. A similar decrease in sensitivity, and therefore the ability to correctly determine the glomerular permeability coefficient of albumin, occurred in vivo at higher offset. Finding the offset that yields accurate and linear data are essential for quantitative analysis when high sensitivity is required.
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Affiliation(s)
- Ruben M Sandoval
- Indiana University School of Medicine; Indianapolis, IN USA ; The Roudebush VA; Indianapolis, IN USA
| | - Exing Wang
- Department of Cellular and Structural Biology; University of Texas Health Science Center; San Antonio, TX USA
| | - Bruce A Molitoris
- Indiana University School of Medicine; Indianapolis, IN USA ; The Roudebush VA; Indianapolis, IN USA
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67
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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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Orden S, De Pablo C, Rios-Navarro C, Martinez-Cuesta MA, Peris JE, Barrachina MD, Esplugues JV, Alvarez A. Efavirenz induces interactions between leucocytes and endothelium through the activation of Mac-1 and gp150,95. J Antimicrob Chemother 2013; 69:995-1004. [PMID: 24275118 DOI: 10.1093/jac/dkt468] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES The potential cardiovascular (CV) toxicity associated with combined antiretroviral therapy (cART) has been attributed mainly to the nucleoside reverse transcriptase inhibitors abacavir and didanosine. However, the other two components of cART--non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs)--may also be implicated, either directly or by influencing the action of the other drugs. This study evaluates the acute direct effects of the NNRTIs efavirenz and nevirapine and one of the most widely employed PIs, lopinavir, on leucocyte-endothelium interactions, a hallmark of CV disease. METHODS Drugs were analysed in vitro in human cells (interactions of peripheral blood polymorphonuclear or mononuclear cells with human umbilical vein endothelial cells) using a flow chamber system, and in vivo in rat mesenteric vessels by means of intravital microscopy. The expression of adhesion molecules in leucocytes and endothelial cells was studied by flow cytometry, and the role of these molecules in white cell recruitment was evaluated by pre-treating human cells or rats with blocking antibodies. RESULTS Efavirenz and nevirapine, but not lopinavir, increased the rolling flux and adhesion of leucocytes in vitro and in vivo while inducing emigration in rat venules. Efavirenz, but not nevirapine, augmented the levels of CD11b, CD11c and CD18 in neutrophils and monocytes. The actions of efavirenz, but not of nevirapine, were reversed by antibodies against Mac-1 (CD11b/CD18), gp150,95 (CD11c/CD18) or ICAM-1 (CD54). CONCLUSIONS NNRTIs, but not PIs, interfere with leucocyte-endothelial interactions. However, differences between efavirenz and nevirapine suggest a specific CV profile for each compound.
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Affiliation(s)
- Samuel Orden
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
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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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Antony PMA, Trefois C, Stojanovic A, Baumuratov AS, Kozak K. Light microscopy applications in systems biology: opportunities and challenges. Cell Commun Signal 2013; 11:24. [PMID: 23578051 PMCID: PMC3627909 DOI: 10.1186/1478-811x-11-24] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/28/2013] [Indexed: 01/05/2023] Open
Abstract
Biological systems present multiple scales of complexity, ranging from molecules to entire populations. Light microscopy is one of the least invasive techniques used to access information from various biological scales in living cells. The combination of molecular biology and imaging provides a bottom-up tool for direct insight into how molecular processes work on a cellular scale. However, imaging can also be used as a top-down approach to study the behavior of a system without detailed prior knowledge about its underlying molecular mechanisms. In this review, we highlight the recent developments on microscopy-based systems analyses and discuss the complementary opportunities and different challenges with high-content screening and high-throughput imaging. Furthermore, we provide a comprehensive overview of the available platforms that can be used for image analysis, which enable community-driven efforts in the development of image-based systems biology.
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Affiliation(s)
- Paul Michel Aloyse Antony
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Christophe Trefois
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Aleksandar Stojanovic
- Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg, Luxembourg City, Luxembourg
| | | | - Karol Kozak
- Light Microscopy Centre (LMSC), Institute for Biochemistry, ETH Zurich, Zurich, Switzerland
- Medical Faculty, Technical University Dresden, Dresden, Germany
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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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