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Brooks HL, de Castro Brás LE, Brunt KR, Sylvester MA, Parvatiyar MS, Sirish P, Bansal SS, Sule R, Eadie AL, Knepper MA, Fenton RA, Lindsey ML, DeLeon-Pennell KY, Gomes AV. Guidelines on antibody use in physiology research. Am J Physiol Renal Physiol 2024; 326:F511-F533. [PMID: 38234298 DOI: 10.1152/ajprenal.00347.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 01/19/2024] Open
Abstract
Antibodies are one of the most used reagents in scientific laboratories and are critical components for a multitude of experiments in physiology research. Over the past decade, concerns about many biological methods, including those that use antibodies, have arisen as several laboratories were unable to reproduce the scientific data obtained in other laboratories. The lack of reproducibility could be largely attributed to inadequate reporting of detailed methods, no or limited verification by authors, and the production and use of unvalidated antibodies. The goal of this guideline article is to review best practices concerning commonly used techniques involving antibodies, including immunoblotting, immunohistochemistry, and flow cytometry. Awareness and integration of best practices will increase the rigor and reproducibility of these techniques and elevate the quality of physiology research.
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Affiliation(s)
- Heddwen L Brooks
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana, United States
| | | | - Keith R Brunt
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Saint John, New Brunswick, Canada
| | - Megan A Sylvester
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona, United States
| | - Michelle S Parvatiyar
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
| | - Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California, United States
| | - Shyam S Bansal
- Department of Cellular and Molecular Physiology, Heart and Vascular Institute, Pennsylvania State University Hershey Medical Center, Hershey, Pennsylvania, United States
| | - Rasheed Sule
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States
| | - Ashley L Eadie
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Saint John, New Brunswick, Canada
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Merry L Lindsey
- School of Graduate Studies, Meharry Medical College, Nashville, Tennessee, United States
- Research Service, Nashville Veterans Affairs Medical Center, Nashville, Tennessee, United States
| | - Kristine Y DeLeon-Pennell
- Division of Cardiology, Department of Medicine, School of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
- Research Service, Ralph H Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California, United States
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2
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Faklaris O, Bancel-Vallée L, Dauphin A, Monterroso B, Frère P, Geny D, Manoliu T, de Rossi S, Cordelières FP, Schapman D, Nitschke R, Cau J, Guilbert T. Quality assessment in light microscopy for routine use through simple tools and robust metrics. J Biophys Biochem Cytol 2022; 221:213512. [PMID: 36173380 PMCID: PMC9526251 DOI: 10.1083/jcb.202107093] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 04/04/2022] [Accepted: 08/31/2022] [Indexed: 11/22/2022] Open
Abstract
Although there is a need to demonstrate reproducibility in light microscopy acquisitions, the lack of standardized guidelines monitoring microscope health status over time has so far impaired the widespread use of quality control (QC) measurements. As scientists from 10 imaging core facilities who encounter various types of projects, we provide affordable hardware and open source software tools, rigorous protocols, and define reference values to assess QC metrics for the most common fluorescence light microscopy modalities. Seven protocols specify metrics on the microscope resolution, field illumination flatness, chromatic aberrations, illumination power stability, stage drift, positioning repeatability, and spatial-temporal noise of camera sensors. We designed the MetroloJ_QC ImageJ/Fiji Java plugin to incorporate the metrics and automate analysis. Measurements allow us to propose an extensive characterization of the QC procedures that can be used by any seasoned microscope user, from research biologists with a specialized interest in fluorescence light microscopy through to core facility staff, to ensure reproducible and quantifiable microscopy results.
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Affiliation(s)
- Orestis Faklaris
- Montpellier Ressources Imagerie, Biocampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Leslie Bancel-Vallée
- Montpellier Ressources Imagerie, Biocampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Aurélien Dauphin
- Unite Genetique et Biologie du Développement U934, PICT-IBiSA, Institut Curie, INSERM, CNRS, PSL Research University, Paris, France
| | - Baptiste Monterroso
- Prism, Institut de Biologie Valrose, CNRS UMR 7277, INSERM 1091, University of Nice Sophia Antipolis - Parc Valrose, Nice, France
| | - Perrine Frère
- Plate-forme d'Imagerie de Tenon, UMR_S 1155, Hôpital Tenon, Paris, France
| | - David Geny
- Institut de Psychiatrie Et Neurosciences de Paris, INSERM U1266, Paris, France
| | - Tudor Manoliu
- Gustave Roussy, Université Paris-Saclay, Plate-forme Imagerie et Cytométrie, UMS AMMICa. Villejuif, France
| | - Sylvain de Rossi
- Montpellier Ressources Imagerie, Biocampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Fabrice P Cordelières
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, UMS 3420, US 4, Bordeaux, France
| | - Damien Schapman
- Université of Rouen Normandie, INSERM, Plate-Forme de Recherche en Imagerie Cellulaire de Normandie, Rouen, France
| | - Roland Nitschke
- Life Imaging Center and Signalling Research Centres CIBSS and BIOSS, University Freiburg, Freiburg, Germany
| | - Julien Cau
- Montpellier Ressources Imagerie, Biocampus, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Thomas Guilbert
- Institut Cochin, INSERM (U1016), CNRS (UMR 8104), Universite de Paris (UMR-S1016), Paris, France
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Homsirikamol C, Suvanasuthi S, Viravaidya-Pasuwat K. Inclusion of IR-820 into Soybean-Phosphatides-Based Nanoparticles for Near-Infrared-Triggered Release and Endolysosomal Escape in HaCaT Keratinocytes at Insignificant Cytotoxic Level. Int J Nanomedicine 2020; 15:8717-8737. [PMID: 33192063 PMCID: PMC7654534 DOI: 10.2147/ijn.s267119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/22/2020] [Indexed: 01/15/2023] Open
Abstract
PURPOSE The degradation of drugs within endolysosomes has been widely addressed as a cause of poor bioavailability. One of the strategies to allow molecules to escape from a destructive fate is to introduce a photosensitizing moiety into a drug carrier enabling the permeabilization of endosomes and endolysosomes upon irradiation. This paper presents an alternative delivery nanosystem composed of cost-effective soybean phosphatides mixed with IR-820, a near-infrared (NIR) sensitizer, to load various active compounds and trigger an endolysosomal escape with a low cytotoxic effect. METHODS IR-820-incorporated phosphatides-based nanoparticles were formulated using a thin-film hydration method to encapsulate different molecular probes and a drug model. The nanoparticles were characterized in vitro using dynamic light scattering, transmission electron microscopy, as well as ultraviolet-visible and fluorescence spectroscopy techniques. The NIR-corresponding generation of the photochemical products, the content release, and the cytotoxicity toward the HaCaT keratinocyte cell line were evaluated. The cellular internalization and endolysosomal escape were monitored using a cytochemical marker and fluorescent probes with a colocalization analysis. RESULTS The IR-820-combined nanoparticles revealed the NIR-triggered changes in the singlet oxygen presence, nanoparticle architecture, and release rate without being cytotoxic. Additionally, the nanoplatform appeared to enhance cellular uptake of the macromolecules. The localization of the cytochemical marker and the colocalization analysis on the fluorescence signals of the encapsulated fluorophore and the lysosome-labeling reporter implied the transient endolysosomal escape of the cargo within the HaCaT cells after NIR irradiation. CONCLUSION The inclusion of IR-820 into a soybean-phosphatides base ingredient provides NIR responsiveness, particularly the endolysosomal escape of the payload, to the formulated nanoparticles, while preserving the beneficial properties as a drug carrier. This alternative delivery nanomedicine system has future potential to provide high bioavailability of cytosolic drugs utilizing time- and spatial-controllable NIR triggerability as well as the synergistic therapeutic effects with NIR-biomodulation.
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Affiliation(s)
- Chaiyarerk Homsirikamol
- Mammalian Cell Culture Laboratory, Biological Engineering Program, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Saroj Suvanasuthi
- Hair Diseases and Hair Transplantation Division, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Kwanchanok Viravaidya-Pasuwat
- Mammalian Cell Culture Laboratory, Biological Engineering Program, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
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Lunde A, Glover JC. A versatile toolbox for semi-automatic cell-by-cell object-based colocalization analysis. Sci Rep 2020; 10:19027. [PMID: 33149236 PMCID: PMC7643144 DOI: 10.1038/s41598-020-75835-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 10/14/2020] [Indexed: 11/09/2022] Open
Abstract
Differential fluorescence labeling and multi-fluorescence imaging followed by colocalization analysis is commonly used to investigate cellular heterogeneity in situ. This is particularly important when investigating the biology of tissues with diverse cell types. Object-based colocalization analysis (OBCA) tools can employ automatic approaches, which are sensitive to errors in cell segmentation, or manual approaches, which can be impractical and tedious. Here, we present a novel set of tools for OBCA using a semi-automatic approach, consisting of two ImageJ plugins, a Microsoft Excel macro, and a MATLAB script. One ImageJ plugin enables customizable processing of multichannel 3D images for enhanced visualization of features relevant to OBCA, and another enables semi-automatic colocalization quantification. The Excel macro and the MATLAB script enable data organization and 3D visualization of object data across image series. The tools are well suited for experiments involving complex and large image data sets, and can be used in combination or as individual components, allowing flexible, efficient and accurate OBCA. Here we demonstrate their utility in immunohistochemical analyses of the developing central nervous system, which is characterized by complexity in the number and distribution of cell types, and by high cell packing densities, which can both create challenging situations for OBCA.
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Affiliation(s)
- Anders Lunde
- Laboratory of Neural Development and Optical Recording (NDEVOR), Division of Physiology, Department of Molecular Medicine, University of Oslo, Blindern, 1105, Oslo, Norway
| | - Joel C Glover
- Laboratory of Neural Development and Optical Recording (NDEVOR), Division of Physiology, Department of Molecular Medicine, University of Oslo, Blindern, 1105, Oslo, Norway.
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5
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Evans LW, Stratton MS, Ferguson BS. Dietary natural products as epigenetic modifiers in aging-associated inflammation and disease. Nat Prod Rep 2020; 37:653-676. [PMID: 31993614 PMCID: PMC7577396 DOI: 10.1039/c9np00057g] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Covering: up to 2020Chronic, low-grade inflammation is linked to aging and has been termed "inflammaging". Inflammaging is considered a key contributor to the development of metabolic dysfunction and a broad spectrum of diseases or disorders including declines in brain and heart function. Genome-wide association studies (GWAS) coupled with epigenome-wide association studies (EWAS) have shown the importance of diet in the development of chronic and age-related diseases. Moreover, dietary interventions e.g. caloric restriction can attenuate inflammation to delay and/or prevent these diseases. Common themes in these studies entail the use of phytochemicals (plant-derived compounds) or the production of short chain fatty acids (SCFAs) as epigenetic modifiers of DNA and histone proteins. Epigenetic modifications are dynamically regulated and as such, serve as potential therapeutic targets for the treatment or prevention of age-related disease. In this review, we will focus on the role for natural products that include phytochemicals and short chain fatty acids (SCFAs) as regulators of these epigenetic adaptations. Specifically, we discuss regulators of methylation, acetylation and acylation, in the protection from chronic inflammation driven metabolic dysfunction and deterioration of neurocognitive and cardiac function.
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Affiliation(s)
- Levi W Evans
- Department of Nutrition, University of Nevada, Reno, NV 89557, USA.
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6
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Brooks HL, Lindsey ML. Guidelines for authors and reviewers on antibody use in physiology studies. Am J Physiol Heart Circ Physiol 2018; 314:H724-H732. [PMID: 29351459 PMCID: PMC6048465 DOI: 10.1152/ajpheart.00512.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Antibody use is a critical component of cardiovascular physiology research, and antibodies are used to monitor protein abundance (immunoblot analysis) and protein expression and localization (in tissue by immunohistochemistry and in cells by immunocytochemistry). With ongoing discussions on how to improve reproducibility and rigor, the goal of this review is to provide best practice guidelines regarding how to optimize antibody use for increased rigor and reproducibility in both immunoblot analysis and immunohistochemistry approaches. Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/guidelines-on-antibody-use-in-physiology-studies/.
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Affiliation(s)
- Heddwen L Brooks
- Department of Physiology, Pharmacology and Medicine, Sarver Heart Center, College of Medicine, University of Arizona , Tucson, Arizona
| | - Merry L Lindsey
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi.,Research Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center , Jackson, Mississippi
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Abstract
Labeling fixed brain tissue with fluorescent synaptic and cellular markers can help assess circuit connectivity. Despite the diffraction-limited resolution of light microscopy there are several approaches to identify synaptic contacts onto a cell-of-interest. Understanding which image quantification methods can be applied to estimate cellular and synaptic connectivity at the light microscope level is beneficial to answer a range of questions, from mapping appositions between cellular structures or synaptic proteins to assessing synaptic contact density onto a cell-of-interest. This chapter provides the reader with details of the image analysis methods that can be applied to quantify in situ connectivity patterns at the level of cellular contacts and synaptic appositions.
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Affiliation(s)
- Mrinalini Hoon
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA.
| | - Raunak Sinha
- Department of Physiology and Biophysics, University of Washington, Seattle, 98195, WA, USA
| | - Haruhisa Okawa
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA.
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8
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Pastorek L, Sobol M, Hozák P. Colocalization coefficients evaluating the distribution of molecular targets in microscopy methods based on pointed patterns. Histochem Cell Biol 2016; 146:391-406. [PMID: 27460592 PMCID: PMC5037163 DOI: 10.1007/s00418-016-1467-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2016] [Indexed: 01/28/2023]
Abstract
In biomedical studies, the colocalization is commonly understood as the overlap between distinctive labelings in images. This term is usually associated especially with quantitative evaluation of the immunostaining in fluorescence microscopy. On the other hand, the evaluation of the immunolabeling colocalization in the electron microscopy images is still under-investigated and biased by the subjective and non-quantitative interpretation of the image data. We introduce a novel computational technique for quantifying the level of colocalization in pointed patterns. Our approach follows the idea included in the widely used Manders' colocalization coefficients in fluorescence microscopy and represents its counterpart for electron microscopy. In presented methodology, colocalization is understood as the product of the spatial interactions at the single-particle (single-molecule) level. Our approach extends the current significance testing in the immunoelectron microscopy images and establishes the descriptive colocalization coefficients. To demonstrate the performance of the proposed coefficients, we investigated the level of spatial interactions of phosphatidylinositol 4,5-bisphosphate with fibrillarin in nucleoli. We compared the electron microscopy colocalization coefficients with Manders' colocalization coefficients for confocal microscopy and super-resolution structured illumination microscopy. The similar tendency of the values obtained using different colocalization approaches suggests the biological validity of the scientific conclusions. The presented methodology represents a good basis for further development of the quantitative analysis of immunoelectron microscopy data and can be used for studying molecular interactions at the ultrastructural level. Moreover, this methodology can be applied also to the other super-resolution microscopy techniques focused on characterization of discrete pointed structures.
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Affiliation(s)
- Lukáš Pastorek
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Margarita Sobol
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
- Laboratory of Epigenetics of the Cell Nucleus, Division BIOCEV, Institute of Molecular Genetics of the ASCR v. v. i., Průmyslová 595, 252 50, Vestec, Czech Republic.
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9
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Strauss JA, Shaw CS, Bradley H, Wilson OJ, Dorval T, Pilling J, Wagenmakers AJM. Immunofluorescence microscopy of SNAP23 in human skeletal muscle reveals colocalization with plasma membrane, lipid droplets, and mitochondria. Physiol Rep 2016; 4:e12662. [PMID: 26733245 PMCID: PMC4760398 DOI: 10.14814/phy2.12662] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 11/24/2022] Open
Abstract
Synaptosomal-associated protein 23 (SNAP23) is a SNARE protein expressed abundantly in human skeletal muscle. Its established role is to mediate insulin-stimulated docking and fusion of glucose transporter 4 (GLUT4) with the plasma membrane. Recent in vitro research has proposed that SNAP23 may also play a role in the fusion of growing lipid droplets (LDs) and the channeling of LD-derived fatty acids (FAs) into neighboring mitochondria for β-oxidation. This study investigates the subcellular distribution of SNAP23 in human skeletal muscle using immunofluorescence microscopy to confirm that SNAP23 localization supports the three proposed metabolic roles. Percutaneous biopsies were obtained from the m. vastus lateralis of six lean, healthy males in the rested, overnight fasted state. Cryosections were stained with antibodies targeting SNAP23, the mitochondrial marker cytochrome c oxidase and the plasma membrane marker dystrophin, whereas intramuscular LDs were stained using the neutral lipid dye oil red O. SNAP23 displayed areas of intense punctate staining in the intracellular regions of all muscle fibers and continuous intense staining in peripheral regions of the cell. Quantitation of confocal microscopy images showed colocalization of SNAP23 with the plasma membrane marker dystrophin (Pearson's correlation coefficient r = 0.50 ± 0.01). The intense punctate intracellular staining colocalized primarily with the mitochondrial marker cytochrome C oxidase (r = 0.50 ± 0.012) and to a lesser extent with LDs (r = 0.21 ± 0.01) visualized with oil red O. We conclude that the observed subcellular distribution of SNAP23 in human skeletal muscle supports the three aforementioned metabolic roles.
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Affiliation(s)
- Juliette A Strauss
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Christopher S Shaw
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia
| | - Helen Bradley
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, UK
| | - Oliver J Wilson
- Institute for Sport, Physical Activity and Leisure, Carnegie Faculty, Leeds Beckett University, Leeds, UK
| | | | | | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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Freeman K, Tao W, Sun H, Soonpaa MH, Rubart M. In situ three-dimensional reconstruction of mouse heart sympathetic innervation by two-photon excitation fluorescence imaging. J Neurosci Methods 2014; 221:48-61. [PMID: 24056230 PMCID: PMC3858460 DOI: 10.1016/j.jneumeth.2013.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/06/2013] [Accepted: 09/08/2013] [Indexed: 12/26/2022]
Abstract
BACKGROUND Sympathetic nerve wiring in the mammalian heart has remained largely unexplored. Resolving the wiring diagram of the cardiac sympathetic network would help establish the structural underpinnings of neurocardiac coupling. NEW METHOD We used two-photon excitation fluorescence microscopy, combined with a computer-assisted 3-D tracking algorithm, to map the local sympathetic circuits in living hearts from adult transgenic mice expressing enhanced green fluorescent protein (EGFP) in peripheral adrenergic neurons. RESULTS Quantitative co-localization analyses confirmed that the intramyocardial EGFP distribution recapitulated the anatomy of the sympathetic arbor. In the left ventricular subepicardium of the uninjured heart, the sympathetic network was composed of multiple subarbors, exhibiting variable branching and looping topology. Axonal branches did not overlap with each other within their respective parental subarbor nor with neurites of annexed subarbors. The sympathetic network in the border zone of a 2-week-old myocardial infarction was characterized by substantive rewiring, which included spatially heterogeneous loss and gain of sympathetic fibers and formation of multiple, predominately nested, axon loops of widely variable circumference and geometry. COMPARISON WITH EXISTING METHODS In contrast to mechanical tissue sectioning methods that may involve deformation of tissue and uncertainty in registration across sections, our approach preserves continuity of structure, which allows tracing of neurites over distances, and thus enables derivation of the three-dimensional and topological morphology of cardiac sympathetic nerves. CONCLUSIONS Our assay should be of general utility to unravel the mechanisms governing sympathetic axon spacing during development and disease.
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Affiliation(s)
- Kim Freeman
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202
| | - Wen Tao
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202
| | - Hongli Sun
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202
| | - Mark H. Soonpaa
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202
| | - Michael Rubart
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 West Walnut Street, Indianapolis, IN 46202
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Andersen H, Parhamifar L, Moein Moghimi S. Uptake and Intracellular Trafficking of Nanocarriers. INTRACELLULAR DELIVERY II 2014. [DOI: 10.1007/978-94-017-8896-0_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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12
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Bauer NC, Corbett AH, Doetsch PW. Automated quantification of the subcellular localization of multicompartment proteins via Q-SCAn. Traffic 2013; 14:1200-8. [PMID: 24034606 PMCID: PMC3836439 DOI: 10.1111/tra.12118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/06/2013] [Accepted: 09/11/2013] [Indexed: 01/19/2023]
Abstract
In eukaryotic cells, proteins can occupy multiple intracellular compartments and even move between compartments to fulfill critical biological functions or respond to cellular signals. Examples include transcription factors that reside in the cytoplasm but are mobilized to the nucleus as well as dual-purpose DNA repair proteins that are charged with simultaneously maintaining the integrity of both the nuclear and mitochondrial genomes. While numerous methods exist to study protein localization and dynamics, automated methods to quantify the relative amounts of proteins that occupy multiple subcellular compartments have not been extensively developed. To address this need, we present a rapid, automated method termed quantitative subcellular compartmentalization analysis (Q-SCAn). To develop this method, we exploited the facile molecular biology of the budding yeast, Saccharomyces cerevisiae. Individual subcellular compartments are defined by a fluorescent marker protein and the intensity of a target GFP-tagged protein is then quantified within each compartment. To validate Q-SCAn, we analyzed relocalization of the transcription factor Yap1 following oxidative stress and then extended the approach to multicompartment localization by examining two DNA repair proteins critical for the base excision repair pathway, Ntg1 and Ung1. Our findings demonstrate the utility of Q-SCAn for quantitative analysis of the subcellular distribution of multicompartment proteins.
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Affiliation(s)
- Nicholas C. Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Anita H. Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, 30322, United States
| | - Paul W. Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, 30322, United States
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 30322, United States
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA, 30322, United States
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13
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Wolters PJ, Collard HR, Jones KD. Pathogenesis of idiopathic pulmonary fibrosis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2013; 9:157-79. [PMID: 24050627 DOI: 10.1146/annurev-pathol-012513-104706] [Citation(s) in RCA: 555] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fibrosing interstitial lung disease associated with aging that is characterized by the histopathological pattern of usual interstitial pneumonia. Although an understanding of the pathogenesis of IPF is incomplete, recent advances delineating specific clinical and pathologic features of IPF have led to better definition of the molecular pathways that are pathologically activated in the disease. In this review we highlight several of these advances, with a focus on genetic predisposition to IPF and how genetic changes, which occur primarily in epithelial cells, lead to activation of profibrotic pathways in epithelial cells. We then discuss the pathologic changes within IPF fibroblasts and the extracellular matrix, and we conclude with a summary of how these profibrotic pathways may be interrelated.
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Affiliation(s)
- Paul J Wolters
- Department of Medicine, School of Medicine, University of California, San Francisco, California 94143; ,
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14
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Jones BL, VanLoozen J, Kim MH, Miles SJ, Dunham CM, Williams LD, Snell TW. Stress granules form in Brachionus manjavacas (Rotifera) in response to a variety of stressors. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:375-84. [PMID: 23856158 DOI: 10.1016/j.cbpa.2013.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 07/03/2013] [Accepted: 07/04/2013] [Indexed: 02/05/2023]
Abstract
Many eukaryotes share a common response to environmental stresses. The responses include reorganization of cellular organelles and proteins. Similar stress responses between divergent species suggest that these protective mechanisms may have evolved early and been retained from the earliest eukaryotic ancestors. Many eukaryotic cells have the capacity to sequester proteins and mRNAs into transient stress granules (SGs) that protect most cellular mRNAs (Anderson and Kedersha, 2008). Our observations extend the phylogenetic range of SGs from trypanosomatids, insects, yeast and mammalian cells, where they were first described, to a species of the lophotrochozoan animal phylum Rotifera. We focus on the distribution of three proteins known to be associated with both ribosomes and SG formation: eukaryotic initiation factors eIF3B, eIF4E and T-cell-restricted intracellular antigen 1. We found that these three proteins co-localize to SGs in rotifers in response to temperature stress, osmotic stress and nutrient deprivation as has been described in other eukaryotes. We have also found that the large ribosomal subunit fails to localize to the SGs in rotifers. Furthermore, the SGs in rotifers disperse once the environmental stress is removed as demonstrated in yeast and mammalian cells. These results are consistent with SG formation in trypanosomatids, insects, yeast and mammalian cells, further supporting the presence of this protective mechanism early in the evolution of eukaryotes.
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Affiliation(s)
- Brande L Jones
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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15
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Lissner S, Hsieh CJ, Nold L, Bannert K, Bodammer P, Sultan A, Seidler U, Graeve L, Lamprecht G. The PDZ-interaction of the intestinal anion exchanger downregulated in adenoma (DRA; SLC26A3) facilitates its movement into Rab11a-positive recycling endosomes. Am J Physiol Gastrointest Liver Physiol 2013; 304:G980-90. [PMID: 23578788 DOI: 10.1152/ajpgi.00132.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Electroneutral NaCl absorption in the ileum and colon is mediated by downregulated in adenoma (DRA) (Cl⁻/HCO₃⁻ exchanger; SLC26A3) and Na⁺/H⁺ exchanger 3 (NHE3, SLC9A3). Surface expression of transport proteins undergoes basal and regulated recycling by endo- and exocytosis. Expression and activity of DRA in the plasma membrane depend on intact lipid rafts, phosphatidylinositol 3-kinase (PI3-kinase), and the PDZ interaction of DRA. However, it is unknown how the PDZ interaction of DRA affects its trafficking to the cell surface. Therefore, the (re)cycling pathway of DRA was investigated in HEK cells stably expressing enhanced green fluorescent protein (EGFP)-DRA or EGFP-DRA-ETKFminus (a mutant lacking the PDZ interaction motif). Early, late, and recycling endosomes were immunoisolated by precipitating stably transfected mCherry-hemagglutinin (HA)-Rab5a, -7a, or -11a. EGFP-DRA and EGFP-DRA-ETKFminus were equally present in early endosomes. In recycling endosomes, wild-type DRA was preferentially present, whereas, in late endosomes, DRA-ETKF-minus dominated. Correspondingly, EGFP-DRA colocalized with mCherry-HA-Rab11a in recycling endosomes, whereas EGFP-DRA-ETKFminus colocalized with mCherry-HA-Rab7a in late endosomes. Functionally, this different distribution was reflected by a shorter half-life of the mutant DRA. Transient expression of dominant-negative Rab11a(S25N) inhibited the activity (-17%, P < 0.05) and the cell surface expression of DRA (-30%, P < 0.05). Transient transfection of Rab4a or its dominant-negative mutant Rab4a(S22N) was without effect and thus excluded participation of the rapid recycling pathway. Taken together, the PDZ interaction of DRA facilitates its movement into Rab11a-positive recycling endosomes, from where it is inserted in the plasma membrane. A scenario emerges where specific PDZ adaptor proteins are present along several compartments of the endocytosis-recycling pathway.
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Affiliation(s)
- S Lissner
- 1st Medical Department, University of Tübingen, Tübingen, Germany
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16
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Liu G, Cheresh P, Kamp DW. Molecular basis of asbestos-induced lung disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2013; 8:161-87. [PMID: 23347351 DOI: 10.1146/annurev-pathol-020712-163942] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Asbestos causes asbestosis and malignancies by molecular mechanisms that are not fully understood. The modes of action underlying asbestosis, lung cancer, and mesothelioma appear to differ depending on the fiber type, lung clearance, and genetics. After reviewing the key pathologic changes following asbestos exposure, we examine recently identified pathogenic pathways, with a focus on oxidative stress. Alveolar epithelial cell apoptosis, which is an important early event in asbestosis, is mediated by mitochondria- and p53-regulated death pathways and may be modulated by the endoplasmic reticulum. We review mitochondrial DNA (mtDNA)-damage and -repair mechanisms, focusing on 8-oxoguanine DNA glycosylase, as well as cross talk between reactive oxygen species production, mtDNA damage, p53, OGG1, and mitochondrial aconitase. These new insights into the molecular basis of asbestos-induced lung diseases may foster the development of novel therapeutic targets for managing degenerative diseases (e.g., asbestosis and idiopathic pulmonary fibrosis), tumors, and aging, for which effective management is lacking.
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Affiliation(s)
- Gang Liu
- Clinical Research Center, Affiliated Hospital of Guangdong Medical College, Zhangjiang, China.
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17
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Herazo-Maya JD, Kaminski N. Personalized medicine: applying 'omics' to lung fibrosis. Biomark Med 2013; 6:529-40. [PMID: 22917154 DOI: 10.2217/bmm.12.38] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF), the most common fibrotic lung disease, is a chronic disease of unknown etiology with a very high mortality. Personalized medicine focuses on the use of the individual's molecular and 'omic' (i.e., genomic, epigenomic and proteomic) information to direct more efficient and cost-effective strategies for prevention, diagnosis, outcome prediction and treatment of diseases. In this review, we describe the use and promise of applying 'omic' technologies to the familial and sporadic forms of IPF as a means to personalize diagnosis and outcome prediction in IPF. The validation and implementation of such approaches will be crucial to personalize IPF patient care, prioritize lung transplant and stratify patients for drug studies, as well as, in the future, predict response to therapies as they emerge.
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Affiliation(s)
- Jose D Herazo-Maya
- Dorothy P & Richard P Simmons Center for Interstitial Lung Disease, Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, 3459 5th Avenue, Pittsburgh, PA 15261, USA
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18
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Tripathi R, Boschetti C, McGee B, Tunnacliffe A. Trafficking of bdelloid rotifer late embryogenesis abundant proteins. ACTA ACUST UNITED AC 2012; 215:2786-94. [PMID: 22837450 DOI: 10.1242/jeb.071647] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The bdelloid rotifer Adineta ricciae is an asexual microinvertebrate that can survive desiccation by entering an ametabolic state known as anhydrobiosis. Two late embryogenesis abundant (LEA) proteins, ArLEA1A and ArLEA1B, have been hypothesized to contribute to desiccation tolerance in these organisms, since in vitro assays suggest that ArLEA1A and ArLEA1B stabilize desiccation-sensitive proteins and membranes, respectively. To examine their functions in vivo, it is important to analyse the cellular distribution of the bdelloid LEA proteins. Bioinformatics predicted their translocation into the endoplasmic reticulum (ER) via an N-terminal ER translocation signal and persistence in the same compartment via a variant C-terminal retention signal sequence ATEL. We assessed the localization of LEA proteins in bdelloids and in a mammalian cell model. The function of the N-terminal sequence of ArLEA1A and ArLEA1B in mediating ER translocation was verified, but our data showed that, unlike classical ER-retention signals, ATEL allows progression from the ER to the Golgi and limited secretion of the proteins into the extracellular medium. These results suggest that the N-terminal ER translocation signal and C-terminal ATEL sequence act together to regulate the distribution of rotifer LEA proteins within intracellular vesicular compartments, as well as the extracellular space. We speculate that this mechanism allows a small number of LEA proteins to offer protection to a large number of desiccation-sensitive molecules and structures both inside and outside cells in the bdelloid rotifer.
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Affiliation(s)
- Rashmi Tripathi
- Cell and Organism Engineering Laboratory, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA, UK
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19
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Gerner MY, Kastenmuller W, Ifrim I, Kabat J, Germain RN. Histo-cytometry: a method for highly multiplex quantitative tissue imaging analysis applied to dendritic cell subset microanatomy in lymph nodes. Immunity 2012; 37:364-76. [PMID: 22863836 DOI: 10.1016/j.immuni.2012.07.011] [Citation(s) in RCA: 312] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/26/2012] [Accepted: 07/17/2012] [Indexed: 01/24/2023]
Abstract
Flow cytometry allows highly quantitative analysis of complex dissociated populations at the cost of neglecting their tissue localization. In contrast, conventional microscopy methods provide spatial information, but visualization and quantification of cellular subsets defined by complex phenotypic marker combinations is challenging. Here, we describe an analytical microscopy method, "histo-cytometry," for visualizing and quantifying phenotypically complex cell populations directly in tissue sections. This technology is based on multiplexed antibody staining, tiled high-resolution confocal microscopy, voxel gating, volumetric cell rendering, and quantitative analysis. We have tested this technology on various innate and adaptive immune populations in murine lymph nodes (LNs) and were able to identify complex cellular subsets and phenotypes, achieving quantitatively similar results to flow cytometry, while also gathering cellular positional information. Here, we employ histo-cytometry to describe the spatial segregation of resident and migratory dendritic cell subsets into specialized microanatomical domains, suggesting an unexpected LN demarcation into discrete functional compartments.
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Affiliation(s)
- Michael Y Gerner
- Lymphocyte Biology Section, Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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20
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Ferreira SA, Correia A, Madureira P, Vilanova M, Gama FM. Unraveling the Uptake Mechanisms of Mannan Nanogel in Bone-Marrow-Derived Macrophages. Macromol Biosci 2012; 12:1172-80. [DOI: 10.1002/mabi.201200075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 05/02/2012] [Indexed: 12/17/2022]
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21
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Shepherd SO, Cocks M, Tipton KD, Ranasinghe AM, Barker TA, Burniston JG, Wagenmakers AJM, Shaw CS. Preferential utilization of perilipin 2-associated intramuscular triglycerides during 1 h of moderate-intensity endurance-type exercise. Exp Physiol 2012; 97:970-80. [DOI: 10.1113/expphysiol.2012.064592] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Shankaran H, Weber TJ, von Neubeck C, Sowa MB. Using imaging methods to interrogate radiation-induced cell signaling. Radiat Res 2012; 177:496-507. [PMID: 22380462 DOI: 10.1667/rr2669.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
There is increasing emphasis on the use of systems biology approaches to define radiation-induced responses in cells and tissues. Such approaches frequently rely on global screening using various high throughput 'omics' platforms. Although these methods are ideal for obtaining an unbiased overview of cellular responses, they often cannot reflect the inherent heterogeneity of the system or provide detailed spatial information. Additionally, performing such studies with multiple sampling time points can be prohibitively expensive. Imaging provides a complementary method with high spatial and temporal resolution capable of following the dynamics of signaling processes. In this review, we utilize specific examples to illustrate how imaging approaches have furthered our understanding of radiation-induced cellular signaling. Particular emphasis is placed on protein colocalization, and oscillatory and transient signaling dynamics.
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Affiliation(s)
- Harish Shankaran
- Computational Biology and Bioinformatics, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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23
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Dwane S, Kiely PA. Tools used to study how protein complexes are assembled in signaling cascades. Bioeng Bugs 2011; 2:247-59. [PMID: 22002082 PMCID: PMC3225741 DOI: 10.4161/bbug.2.5.17844] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 08/19/2011] [Accepted: 08/24/2011] [Indexed: 01/08/2023] Open
Abstract
Most proteins do not function on their own but as part of large signaling complexes that are arranged in every living cell in response to specific environmental cues. Proteins interact with each other either constitutively or transiently and do so with different affinity. When identifying the role played by a protein inside a cell, it is essential to define its particular cohort of binding partners so that the researcher can predict what signaling pathways the protein is engaged in. Once identified and confirmed, the information might allow the interaction to be manipulated by pharmacological inhibitors to help fight disease. In this review, we discuss protein-protein interactions and how they are essential to propagate signals in signaling pathways. We examine some of the high-throughput screening methods and focus on the methods used to confirm specific protein-protein interactions including; affinity tagging, co-immunoprecipitation, peptide array technology and fluorescence microscopy.
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Affiliation(s)
- Susan Dwane
- Department of Life Sciences, and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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24
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Dunn KW, Kamocka MM, McDonald JH. A practical guide to evaluating colocalization in biological microscopy. Am J Physiol Cell Physiol 2011; 300:C723-42. [PMID: 21209361 PMCID: PMC3074624 DOI: 10.1152/ajpcell.00462.2010] [Citation(s) in RCA: 1376] [Impact Index Per Article: 105.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/02/2011] [Indexed: 11/22/2022]
Abstract
Fluorescence microscopy is one of the most powerful tools for elucidating the cellular functions of proteins and other molecules. In many cases, the function of a molecule can be inferred from its association with specific intracellular compartments or molecular complexes, which is typically determined by comparing the distribution of a fluorescently labeled version of the molecule with that of a second, complementarily labeled probe. Although arguably the most common application of fluorescence microscopy in biomedical research, studies evaluating the "colocalization" of two probes are seldom quantified, despite a diversity of image analysis tools that have been specifically developed for that purpose. Here we provide a guide to analyzing colocalization in cell biology studies, emphasizing practical application of quantitative tools that are now widely available in commercial and free image analysis software.
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Affiliation(s)
- Kenneth W Dunn
- Dept. of Medicine, Division of Nephrology, Indiana Univ. Medical Center, Indianapolis, IN 46202, USA.
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25
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Schulson MN, Scriven DRL, Fletcher P, Moore EDW. Couplons in rat atria form distinct subgroups defined by their molecular partners. J Cell Sci 2011; 124:1167-74. [PMID: 21385843 DOI: 10.1242/jcs.080929] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Standard local control theory, which describes Ca(2+) release during excitation-contraction coupling (ECC), assumes that all ryanodine receptor 2 (RyR2) complexes are equivalent. Findings from our laboratory have called this assumption into question. Specifically, we have shown that the RyR2 complexes in ventricular myocytes are different, depending on their location within the cell. This has led us to hypothesize that similar differences occur within the rat atrial cell. To test this hypothesis, we have triple-labelled enzymatically isolated fixed myocytes to examine the distribution and colocalization of RyR2, calsequestrin (Casq), voltage-gated Ca(2+) channels (Ca(v)1.2), the sodium-calcium exchanger (Ncx) and caveolin-3 (Cav3). A number of different surface RyR2 populations were identified, and one of these groups, in which RyR2, Ca(v)1.2 and Ncx colocalized, might provide the structural basis for 'eager' sites of Ca(2+) release in atria. A small percentage of the dyads containing RyR2 and Ca(v)1.2 were colocalized with Cav3, and therefore could be influenced by the signalling molecules it anchors. The majority of the RyR2 clusters were tightly linked to Ca(v)1.2, and, whereas some were coupled to both Ca 1.2 and Ncx, none were with Ncx alone. This suggests that Ca(v)1.2-mediated Ca(2+) -induced Ca(2+) release is the primary method of ECC. The two molecules studied that were found in the interior of atrial cells, RyR2 and Casq, showed significantly less colocalization and a reduced nearest-neighbour distance in the interior, compared with the surface of the cell. These differences might result in a higher excitability for RyR2 in the interior of the cells, facilitating the spread of excitation from the periphery to the centre. We also present morphometric data for all of the molecules studied, as well as for those colocalizations found to be significant.
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Affiliation(s)
- Meredith N Schulson
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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26
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Barlow AL, Macleod A, Noppen S, Sanderson J, Guérin CJ. Colocalization analysis in fluorescence micrographs: verification of a more accurate calculation of pearson's correlation coefficient. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:710-24. [PMID: 20946701 DOI: 10.1017/s143192761009389x] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
One of the most routine uses of fluorescence microscopy is colocalization, i.e., the demonstration of a relationship between pairs of biological molecules. Frequently this is presented simplistically by the use of overlays of red and green images, with areas of yellow indicating colocalization of the molecules. Colocalization data are rarely quantified and can be misleading. Our results from both synthetic and biological datasets demonstrate that the generation of Pearson's correlation coefficient between pairs of images can overestimate positive correlation and fail to demonstrate negative correlation. We have demonstrated that the calculation of a thresholded Pearson's correlation coefficient using only intensity values over a determined threshold in both channels produces numerical values that more accurately describe both synthetic datasets and biological examples. Its use will bring clarity and accuracy to colocalization studies using fluorescent microscopy.
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Affiliation(s)
- Andrew L Barlow
- PerkinElmer, Viscount Centre II, Millburn Hill Road, Warwick University Science Park, Coventry CV4 7HS, UK
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27
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Ramírez O, García A, Rojas R, Couve A, Härtel S. Confined displacement algorithm determines true and random colocalization in fluorescence microscopy. J Microsc 2010; 239:173-83. [PMID: 20701655 DOI: 10.1111/j.1365-2818.2010.03369.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The quantification of colocalizing signals in multichannel fluorescence microscopy images depends on the reliable segmentation of corresponding regions of interest, on the selection of appropriate colocalization coefficients, and on a robust statistical criterion to discriminate true from random colocalization. Here, we introduce a confined displacement algorithm based on image correlation spectroscopy in combination with Manders colocalization coefficients M1(ROI) and M2(ROI) to quantify true and random colocalization of a given florescence pattern. We show that existing algorithms based on block scrambling exaggerate the randomization of fluorescent patterns with resulting inappropriately narrow probability density functions and false significance of true colocalization in terms of p values. We further confine our approach to subcellular compartments and show that true and random colocalization can be analysed for model dendrites and for GABA(B) receptor subunits GABA(B)R1/2 in cultured hippocampal neurons. Together, we demonstrate that the confined displacement algorithm detects true colocalization of specific fluorescence patterns down to subcellular levels.
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Affiliation(s)
- O Ramírez
- Laboratory for Scientific Image Analysis (SCIAN-Lab) at the Anatomy and Developmental Biology Program, ICBM, Universidad de Chile, Santiago, Chile
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28
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Fletcher PA, Scriven DR, Schulson MN, Moore ED. Multi-image colocalization and its statistical significance. Biophys J 2010; 99:1996-2005. [PMID: 20858446 PMCID: PMC2941013 DOI: 10.1016/j.bpj.2010.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 06/29/2010] [Accepted: 07/02/2010] [Indexed: 11/19/2022] Open
Abstract
Accurately localizing molecules within the cell is one of main tasks of modern biology, and colocalization analysis is one of its principal and most often used tools. Despite this popularity, interpretation is often uncertain because colocalization between two or more images is rarely analyzed to determine whether the observed values could have occurred by chance. To address this, we have developed a robust methodology, based on Monte Carlo randomization, to measure the statistical significance of a colocalization. The method works with voxel-based, intensity-based, object-based, and nearest-neighbor metrics. We extend all of these to measure colocalization in images with three colors. We also introduce three new metrics; blob colocalization, where the blob consists of a local maximum surrounded by a three-dimensional group of voxels; cluster diameter, to measure the clustering of fluorophores in three or more images; and the intercluster distance to measure the distance between these clusters. The robustness of these metrics was tested by varying the image thresholds over a broad range, which produced no change in the statistical significance of the colocalizations. A comparison of blob colocalization with voxel and Manders colocalization metrics shows that the different measures produce consistent results with similar values for significance and nonsignificance. Using our methodology, we are able to determine not only whether the labeled molecules colocalize with a probability greater than chance, but also whether they are sequestrated into different compartments. The program, written in C++, is freely available as source, as well as in a Linux version.
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Affiliation(s)
| | | | | | - Edwin D.W. Moore
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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29
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Gonzalez DR, Treuer AV, Castellanos J, Dulce RA, Hare JM. Impaired S-nitrosylation of the ryanodine receptor caused by xanthine oxidase activity contributes to calcium leak in heart failure. J Biol Chem 2010; 285:28938-45. [PMID: 20643651 DOI: 10.1074/jbc.m110.154948] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
S-Nitrosylation is a ubiquitous post-translational modification that regulates diverse biologic processes. In skeletal muscle, hypernitrosylation of the ryanodine receptor (RyR) causes sarcoplasmic reticulum (SR) calcium leak, but whether abnormalities of cardiac RyR nitrosylation contribute to dysfunction of cardiac excitation-contraction coupling remains controversial. In this study, we tested the hypothesis that cardiac RyR2 is hyponitrosylated in heart failure, because of nitroso-redox imbalance. We evaluated excitation-contraction coupling and nitroso-redox balance in spontaneously hypertensive heart failure rats with dilated cardiomyopathy and age-matched Wistar-Kyoto rats. Spontaneously hypertensive heart failure myocytes were characterized by depressed contractility, increased diastolic Ca(2+) leak, hyponitrosylation of RyR2, and enhanced xanthine oxidase derived superoxide. Global S-nitrosylation was decreased in failing hearts compared with nonfailing. Xanthine oxidase inhibition restored global and RyR2 nitrosylation and reversed the diastolic SR Ca(2+) leak, improving Ca(2+) handling and contractility. Together these findings demonstrate that nitroso-redox imbalance causes RyR2 oxidation, hyponitrosylation, and SR Ca(2+) leak, a hallmark of cardiac dysfunction. The reversal of this phenotype by inhibition of xanthine oxidase has important pathophysiologic and therapeutic implications.
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Affiliation(s)
- Daniel R Gonzalez
- Interdisciplinary Stem Cell Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA
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30
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Whitsett JA, Wert SE, Weaver TE. Alveolar surfactant homeostasis and the pathogenesis of pulmonary disease. Annu Rev Med 2010; 61:105-19. [PMID: 19824815 DOI: 10.1146/annurev.med.60.041807.123500] [Citation(s) in RCA: 279] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The alveolar region of the lung creates an extensive epithelial surface that mediates the transfer of oxygen and carbon dioxide required for respiration after birth. Maintenance of pulmonary function depends on the function of type II epithelial cells that synthesize and secrete pulmonary surfactant lipids and proteins, reducing the collapsing forces created at the air-liquid interface in the alveoli. Genetic and acquired disorders associated with the surfactant system cause both acute and chronic lung disease. Mutations in the ABCA3, SFTPA, SFTPB, SFTPC, SCL34A2, and TERT genes disrupt type II cell function and/or surfactant homeostasis, causing neonatal respiratory failure and chronic interstitial lung disease. Defects in GM-CSF receptor function disrupt surfactant clearance, causing pulmonary alveolar proteinosis. Abnormalities in the surfactant system and disruption of type II cell homeostasis underlie the pathogenesis of pulmonary disorders previously considered idiopathic, providing the basis for improved diagnosis and therapies of these rare lung diseases.
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Affiliation(s)
- Jeffrey A Whitsett
- Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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31
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Ljosa V, Carpenter AE. Introduction to the quantitative analysis of two-dimensional fluorescence microscopy images for cell-based screening. PLoS Comput Biol 2009; 5:e1000603. [PMID: 20041172 PMCID: PMC2791844 DOI: 10.1371/journal.pcbi.1000603] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Vebjorn Ljosa
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Anne E. Carpenter
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
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32
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Ghanem MM, Battelli LA, Law BF, Castranova V, Kashon ML, Nath J, Hubbs AF. Coal dust alters beta-naphthoflavone-induced aryl hydrocarbon receptor nuclear translocation in alveolar type II cells. Part Fibre Toxicol 2009; 6:21. [PMID: 19650907 PMCID: PMC2732588 DOI: 10.1186/1743-8977-6-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Accepted: 08/03/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many polycyclic aromatic hydrocarbons (PAHs) can cause DNA adducts and initiate carcinogenesis. Mixed exposures to coal dust (CD) and PAHs are common in occupational settings. In the CD and PAH-exposed lung, CD increases apoptosis and causes alveolar type II (AT-II) cell hyperplasia but reduces CYP1A1 induction. Inflammation, but not apoptosis, appears etiologically associated with reduced CYP1A1 induction in this mixed exposure model. Many AT-II cells in the CD-exposed lungs have no detectable CYP1A1 induction after PAH exposure. Although AT-II cells are a small subfraction of lung cells, they are believed to be a potential progenitor cell for some lung cancers. Because CYP1A1 is induced via ligand-mediated nuclear translocation of the aryl hydrocarbon receptor (AhR), we investigated the effect of CD on PAH-induced nuclear translocation of AhR in AT-II cells isolated from in vivo-exposed rats. Rats received CD or vehicle (saline) by intratracheal (IT) instillation. Three days before sacrifice, half of the rats in each group started daily intraperitoneal injections of the PAH, beta-naphthoflavone (BNF). RESULTS Fourteen days after IT CD exposure and 1 day after the last intraperitoneal BNF injection, AhR immunofluorescence indicated that proportional AhR nuclear expression and the percentage of cells with nuclear AhR were significantly increased in rats receiving IT saline and BNF injections compared to vehicle controls. However, in CD-exposed rats, BNF did not significantly alter the nuclear localization or cytosolic expression of AhR compared to rats receiving CD and oil. CONCLUSION Our findings suggest that during particle and PAH mixed exposures, CD alters the BNF-induced nuclear translocation of AhR in AT-II cells. This provides an explanation for the modification of CYP1A1 induction in these cells. Thus, this study suggests that mechanisms for reduced PAH-induced CYP1A1 activity in the CD exposed lung include not only the effects of inflammation on the lung as a whole, but also reduced PAH-associated nuclear translocation of AhR in an expanded population of AT-II cells.
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Affiliation(s)
- Mohamed M Ghanem
- Genetics and Developmental Biology Program, West Virginia University, Morgantown, WV 26506, USA.
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Bennett BT, Bewersdorf J, Knight KL. Immunofluorescence imaging of DNA damage response proteins: optimizing protocols for super-resolution microscopy. Methods 2009; 48:63-71. [PMID: 19245833 DOI: 10.1016/j.ymeth.2009.02.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 02/15/2009] [Indexed: 10/21/2022] Open
Abstract
Immunofluorescence imaging has provided captivating visual evidence for numerous cellular events, from vesicular trafficking, organelle maturation and cell division to nuclear processes including the appearance of various proteins and chromatin components in distinct foci in response to DNA damaging agents. With the advent of new super-resolution microscope technologies such as 4Pi microscopy, standard immunofluorescence protocols deserve some reevaluation in order to take full advantage of these new technological accomplishments. Here we describe several methodological considerations that will help overcome some of the limitations that may result from the use of currently applied procedures, with particular attention paid to the analysis of possible colocalization of fluorescent signals. We conclude with an example of how application of optimized methods led to a breakthrough in super-resolution imaging of nuclear events occurring in response to DNA damage.
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Affiliation(s)
- Brian T Bennett
- Department of Biochemistry and Molecular Pharmacology, Aaron Lazare Medical Research Building, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Berdiev BK, Qadri YJ, Benos DJ. Assessment of the CFTR and ENaC association. MOLECULAR BIOSYSTEMS 2008; 5:123-7. [PMID: 19156256 DOI: 10.1039/b810471a] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cystic fibrosis (CF) is one of the most common lethal genetic disorders. It results primarily from mutations in the cystic fibrosis transmembrane conductance regulator (cftr) gene. These mutations cause inadequate functioning of CFTR, which in turn leads to the severe disruption of transport function in several epithelia across various organs. Affected organs include the sweat glands, the intestine, and the reproductive system, with the most devastating consequences due to the effects of the disease on airways. Despite aggressive treatment, gradual lung failure is the major life limiting factor in patients with CF. Understanding of the exact manner by which defects in the CFTR lead to lung failure is thus critical. In the CF airway, decreased chloride secretion and increased salt absorption is observed. The decreased chloride secretion appears to be a direct consequence of defective CFTR; however, the increased salt absorption is believed to result from the failure of CFTR to restrict salt absorption through a sodium channel named the epithelial Na(+) channel, ENaC. The mechanism by which CFTR modulates the function of ENaC proteins is still obscure and somewhat controversial. In this short review we will focus on recent findings of a possible direct CFTR and ENaC association.
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Affiliation(s)
- Bakhrom K Berdiev
- Departments of Cell Biology and Physiology and Biophysics, University of Alabama at Birmingham, 1918 University Blvd., MCLM 725, Birmingham, AL 35294-0005, USA. berdiev@.uab.edu
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Horowitz JC, Limper AH. Stress in the ER (endoplasmic reticulum): a matter of life and death for epithelial cells. Am J Respir Crit Care Med 2008; 178:782-3. [PMID: 18832553 DOI: 10.1164/rccm.200807-1138ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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