1
|
Markus MA, Ferrari DP, Alves F, Ramos-Gomes F. Effect of tissue fixation on the optical properties of structural components assessed by non-linear microscopy imaging. BIOMEDICAL OPTICS EXPRESS 2023; 14:3988-4002. [PMID: 37799688 PMCID: PMC10549744 DOI: 10.1364/boe.488453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 10/07/2023]
Abstract
Fixation methods such as formalin are commonly used for the preservation of tissue with the aim of keeping their structure as close as possible to the native condition. However, fixatives chemically interact with tissue molecules, such as collagen in the extracellular matrix (ECM) or myosin, and may thus modify their structure. Taking advantage of the second- and third-harmonic generation (SHG and THG) emission capabilities of such components, we used nonlinear two-photon microscopy (NL2PM) to evaluate the effect that preservation methods, such as chemical fixatives, have on the nonlinear capabilities of protein components within mouse tissues. Our results show that depending on the preservation technique used, the nonlinear capabilities of collagen, lipid droplets and myosin microarchitecture are strongly affected. Parameters of collagen fibers, such as density and branch points, especially in collagen-sparse regions, e.g., in kidneys, were found to be altered upon formalin fixation. Moreover, cryo-freezing drastically reduced SHG signals from myosin. Our findings provide valuable information to select the best tissue fixation method for visualization and quantification of structural proteins, such as collagen and myosin by advanced NL2PM imaging techniques. This may advance the interpretation of the role these proteins play in disease.
Collapse
Affiliation(s)
- M. Andrea Markus
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Daniele P. Ferrari
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Frauke Alves
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
- Clinic of Haematology and Medical Oncology, Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Fernanda Ramos-Gomes
- Translational Molecular Imaging Group,
Max-Planck Institute for Multidisciplinary Sciences, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| |
Collapse
|
2
|
García MJ, Kamaid A, Malacrida L. Label-free fluorescence microscopy: revisiting the opportunities with autofluorescent molecules and harmonic generations as biosensors and biomarkers for quantitative biology. Biophys Rev 2023; 15:709-719. [PMID: 37681086 PMCID: PMC10480099 DOI: 10.1007/s12551-023-01083-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/19/2023] [Indexed: 09/09/2023] Open
Abstract
Over the past decade, the utilization of advanced fluorescence microscopy technologies has presented numerous opportunities to study or re-investigate autofluorescent molecules and harmonic generation signals as molecular biomarkers and biosensors for in vivo cell and tissue studies. The label-free approaches benefit from the endogenous fluorescent molecules within the cell and take advantage of their spectroscopy properties to address biological questions. Harmonic generation can be used as a tool to identify the occurrence of fibrillar or lipid deposits in tissues, by using second and third-harmonic generation microscopy. Combining autofluorescence with novel techniques and tools such as fluorescence lifetime imaging microscopy (FLIM) and hyperspectral imaging (HSI) with model-free analysis of phasor plots has revolutionized the understanding of molecular processes such as cellular metabolism. These tools provide quantitative information that is often hidden under classical intensity-based microscopy. In this short review, we aim to illustrate how some of these technologies and techniques may enable investigation without the need to add a foreign fluorescence molecule that can modify or affect the results. We address some of the most important autofluorescence molecules and their spectroscopic properties to illustrate the potential of these combined tools. We discuss using them as biomarkers and biosensors and, under the lens of this new technology, identify some of the challenges and potentials for future advances in the field.
Collapse
Affiliation(s)
- María José García
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay
- Advanced Bioimaging Unit, Institut Pasteur de Montevideo & Universidad de la República, Montevideo, Uruguay
| | - Andrés Kamaid
- Advanced Bioimaging Unit, Institut Pasteur de Montevideo & Universidad de la República, Montevideo, Uruguay
| | - Leonel Malacrida
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay
- Advanced Bioimaging Unit, Institut Pasteur de Montevideo & Universidad de la República, Montevideo, Uruguay
| |
Collapse
|
3
|
Hazart D, Delhomme B, Oheim M, Ricard C. Label-free, fast, 2-photon volume imaging of the organization of neurons and glia in the enteric nervous system. Front Neuroanat 2023; 16:1070062. [PMID: 36844894 PMCID: PMC9948619 DOI: 10.3389/fnana.2022.1070062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/19/2022] [Indexed: 02/11/2023] Open
Abstract
The enteric nervous system (ENS), sometimes referred to as a "second brain" is a quasi-autonomous nervous system, made up of interconnected plexuses organized in a mesh-like network lining the gastrointestinal tract. Originally described as an actor in the regulation of digestion, bowel contraction, and intestinal secretion, the implications of the ENS in various central neuropathologies has recently been demonstrated. However, with a few exceptions, the morphology and pathologic alterations of the ENS have mostly been studied on thin sections of the intestinal wall or, alternatively, in dissected explants. Precious information on the three-dimensional (3-D) architecture and connectivity is hence lost. Here, we propose the fast, label-free 3-D imaging of the ENS, based on intrinsic signals. We used a custom, fast tissue-clearing protocol based on a high refractive-index aqueous solution to increase the imaging depth and allow us the detection of faint signals and we characterized the autofluorescence (AF) from the various cellular and sub-cellular components of the ENS. Validation by immunofluorescence and spectral recordings complete this groundwork. Then, we demonstrate the rapid acquisition of detailed 3-D image stacks from unlabeled mouse ileum and colon, across the whole intestinal wall and including both the myenteric and submucosal enteric nervous plexuses using a new spinning-disk two-photon (2P) microscope. The combination of fast clearing (less than 15 min for 73% transparency), AF detection and rapid volume imaging [less than 1 min for the acquisition of a z-stack of 100 planes (150*150 μm) at sub-300-nm spatial resolution] opens up the possibility for new applications in fundamental and clinical research.
Collapse
Affiliation(s)
- Doriane Hazart
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Brigitte Delhomme
- Université Paris Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | | | | |
Collapse
|
4
|
Abstract
In this series of papers on light microscopy imaging, we have covered the fundamentals of microscopy, super-resolution microscopy, and lightsheet microscopy. This last review covers multi-photon microscopy with a brief reference to intravital imaging and Brainbow labeling. Multi-photon microscopy is often referred to as two-photon microscopy. Indeed, using two-photon microscopy is by far the most common way of imaging thick tissues; however, it is theoretically possible to use a higher number of photons, and three-photon microscopy is possible. Therefore, this review is titled "multi-photon microscopy." Another term for describing multi-photon microscopy is "non-linear" microscopy because fluorescence intensity at the focal spot depends upon the average squared intensity rather than the squared average intensity; hence, non-linear optics (NLO) is an alternative name for multi-photon microscopy. It is this non-linear relationship (or third exponential power in the case of three-photon excitation) that determines the axial optical sectioning capability of multi-photon imaging. In this paper, the necessity for two-photon or multi-photon imaging is explained, and the method of optical sectioning by multi-photon microscopy is described. Advice is also given on what fluorescent markers to use and other practical aspects of imaging thick tissues. The technique of Brainbow imaging is discussed. The review concludes with a description of intravital imaging of the mouse. © 2023 Wiley Periodicals LLC.
Collapse
|
5
|
Chai RC, McDonald MM. Visualisation of tumour cells in bone in vivo at single-cell resolution. Bone 2022; 158:116113. [PMID: 34273634 DOI: 10.1016/j.bone.2021.116113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/28/2021] [Accepted: 07/09/2021] [Indexed: 12/26/2022]
Abstract
The skeleton is a common site for the establishment of distant metastases. Once cancers occupy bone, the prognosis is poor as disease recurrence and visceral spread is imminent. Understanding the pathways and cellular interactions, which regulate tumour cell seeding, dormancy and growth in bone, is pertinent to improving outcomes for patients with advanced cancers. Advances in imaging techniques have facilitated the development of the concept that the behavior of bone marrow resident cells dictates the fate of tumour cells upon arrival in bone. This review summarises recent findings achieved through intravital imaging. It highlights the importance of developing both longitudinal static and acute dynamic data to develop our understanding of tumour cell engraftment, dormancy, activation and the subsequent establishment of metastases. We also describe how imaging techniques have developed our knowledge of the elements that make up the complex bone microenvironment which tumour cells interact with to survive and grow. We also discuss how through combining these imaging insights with single cell RNA sequencing data, we are entering a new era of research which has the power to define the cell-cell interactions which control tumour cell growth in bone.
Collapse
Affiliation(s)
- Ryan C Chai
- Bone Biology Program, Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia
| | - Michelle M McDonald
- Bone Biology Program, Healthy Ageing Theme, Garvan Institute of Medical Research, Sydney, NSW, Australia; St Vincent's Clinical School, Faculty of Medicine, UNSW Sydney, NSW, Australia.
| |
Collapse
|
6
|
Zhou X, Zhao R, Yanamandra AK, Hoth M, Qu B. Light-Sheet Scattering Microscopy to Visualize Long-Term Interactions Between Cells and Extracellular Matrix. Front Immunol 2022; 13:828634. [PMID: 35154150 PMCID: PMC8831865 DOI: 10.3389/fimmu.2022.828634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/11/2022] [Indexed: 11/16/2022] Open
Abstract
Visualizing interactions between cells and the extracellular matrix (ECM) mesh is important to understand cell behavior and regulatory mechanisms by the extracellular environment. However, long term visualization of three-dimensional (3D) matrix structures remains challenging mainly due to photobleaching or blind spots perpendicular to the imaging plane. Here, we combine label-free light-sheet scattering microcopy (LSSM) and fluorescence microscopy to solve these problems. We verified that LSSM can reliably visualize structures of collagen matrices from different origin including bovine, human and rat tail. The quality and intensity of collagen structure images acquired by LSSM did not decline with time. LSSM offers abundant wavelength choice to visualize matrix structures, maximizing combination possibilities with fluorescently-labelled cells, allowing visualizing of long-term ECM-cell interactions in 3D. Interestingly, we observed ultrathin thread-like structures between cells and matrix using LSSM, which were not observed by normal fluorescence microscopy. Transient local alignment of matrix by cell-applied forces can be observed. In summary, LSSM provides a powerful and robust approach to investigate the complex interplay between cells and ECM.
Collapse
Affiliation(s)
- Xiangda Zhou
- Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg, Germany
| | - Renping Zhao
- Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg, Germany
| | - Archana K Yanamandra
- Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg, Germany.,INM-Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Markus Hoth
- Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg, Germany
| | - Bin Qu
- Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg, Germany.,INM-Leibniz Institute for New Materials, Saarbrücken, Germany
| |
Collapse
|
7
|
Khan A, Ramos-Gomes F, Markus A, Mietsch M, Hinkel R, Alves F. Label-free imaging of age-related cardiac structural changes in non-human primates using multiphoton nonlinear microscopy. BIOMEDICAL OPTICS EXPRESS 2021; 12:7009-7023. [PMID: 34858695 PMCID: PMC8606147 DOI: 10.1364/boe.432102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Heart failure is one of the most common causes of morbidity and mortality. Both maturational abnormalities and age-associated cardiac pathologies contribute to heart failure. Imaging-based assessment to discern detailed cardiac structure at various maturational stages is imperative for understanding mechanisms behind cardiac growth and aging. Using multiphoton nonlinear optical microscopy (NLOM) based label-free imaging, we investigated cardiac structural composition in a human-relevant aging model, the common marmoset monkey (Callithrix jacchus). Animals were divided into three different age groups including neonatal, young adult and old. By devising a unique strategy for segregating collagen and myosin emitted second harmonic generation (SHG) signals, we performed a volumetric assessment of collagen and total scattering tissue (collagen + myosin). Aged marmoset hearts exhibited an increase in collagen and total scattering tissue volume at the sites of severe tissue remodelling indicating age-related cardiac fibrosis. Significantly low scattering tissue volume in neonatal marmoset hearts was attributed to a lack of binding between the myofibrils in maturing cardiac tissue. Comprehensive quantitative assessment of structural composition during maturation and aging of marmoset hearts revealed significant differences in myofibril length, alignment, curvature and angular distribution. In conclusion, label-free high-resolution NLOM facilitates visualization and quantification of subcellular structural features for understanding vital age-related morphological alterations in the marmoset heart.
Collapse
Affiliation(s)
- Amara Khan
- Max-Planck-Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner site Göttingen, 37077 Göttingen, Germany
| | - Fernanda Ramos-Gomes
- Max-Planck-Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany
| | - Andrea Markus
- Max-Planck-Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany
| | - Matthias Mietsch
- DZHK (German Center for Cardiovascular Research), Partner site Göttingen, 37077 Göttingen, Germany
- Laboratory Animal Science Unit, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Rabea Hinkel
- DZHK (German Center for Cardiovascular Research), Partner site Göttingen, 37077 Göttingen, Germany
- Laboratory Animal Science Unit, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
- Stiftung Tierärztliche Hochschule Hannover, Hannover, Germany
| | - Frauke Alves
- Max-Planck-Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner site Göttingen, 37077 Göttingen, Germany
- University Medical Center Göttingen, Institute for Diagnostic and Interventional Radiology & Clinic for Hematology and Medical Oncology, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells,” Göttingen, Germany
| |
Collapse
|
8
|
Anchang CG, Xu C, Raimondo MG, Atreya R, Maier A, Schett G, Zaburdaev V, Rauber S, Ramming A. The Potential of OMICs Technologies for the Treatment of Immune-Mediated Inflammatory Diseases. Int J Mol Sci 2021; 22:ijms22147506. [PMID: 34299122 PMCID: PMC8306614 DOI: 10.3390/ijms22147506] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 07/02/2021] [Accepted: 07/09/2021] [Indexed: 01/08/2023] Open
Abstract
Immune-mediated inflammatory diseases (IMIDs), such as inflammatory bowel diseases and inflammatory arthritis (e.g., rheumatoid arthritis, psoriatic arthritis), are marked by increasing worldwide incidence rates. Apart from irreversible damage of the affected tissue, the systemic nature of these diseases heightens the incidence of cardiovascular insults and colitis-associated neoplasia. Only 40–60% of patients respond to currently used standard-of-care immunotherapies. In addition to this limited long-term effectiveness, all current therapies have to be given on a lifelong basis as they are unable to specifically reprogram the inflammatory process and thus achieve a true cure of the disease. On the other hand, the development of various OMICs technologies is considered as “the great hope” for improving the treatment of IMIDs. This review sheds light on the progressive development and the numerous approaches from basic science that gradually lead to the transfer from “bench to bedside” and the implementation into general patient care procedures.
Collapse
Affiliation(s)
- Charles Gwellem Anchang
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
| | - Cong Xu
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
| | - Maria Gabriella Raimondo
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
| | - Raja Atreya
- Department of Internal Medicine 1, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany;
| | - Andreas Maier
- Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany;
| | - Georg Schett
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
| | - Vasily Zaburdaev
- Max-Planck-Zentrum für Physik und Medizin, 91054 Erlangen, Germany;
- Department of Biology, Mathematics in Life Sciences, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Simon Rauber
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
| | - Andreas Ramming
- Department of Internal Medicine 3—Rheumatology and Immunology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum, 91054 Erlangen, Germany; (C.G.A.); (C.X.); (M.G.R.); (G.S.); (S.R.)
- Correspondence: ; Tel.: +49-9131-8543048; Fax: +49-9131-8536448
| |
Collapse
|
9
|
Checa M, Millan-Solsona R, Mares AG, Pujals S, Gomila G. Fast Label-Free Nanoscale Composition Mapping of Eukaryotic Cells Via Scanning Dielectric Force Volume Microscopy and Machine Learning. SMALL METHODS 2021; 5:e2100279. [PMID: 34928004 DOI: 10.1002/smtd.202100279] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/28/2021] [Indexed: 06/14/2023]
Abstract
Mapping the biochemical composition of eukaryotic cells without the use of exogenous labels is a long-sought objective in cell biology. Recently, it has been shown that composition maps on dry single bacterial cells with nanoscale spatial resolution can be inferred from quantitative nanoscale dielectric constant maps obtained with the scanning dielectric microscope. Here, it is shown that this approach can also be applied to the much more challenging case of fixed and dry eukaryotic cells, which are highly heterogeneous and show micrometric topographic variations. More importantly, it is demonstrated that the main bottleneck of the technique (the long computation times required to extract the nanoscale dielectric constant maps) can be shortcut by using supervised neural networks, decreasing them from weeks to seconds in a wokstation computer. This easy-to-use data-driven approach opens the door for in situ and on-the-fly label free nanoscale composition mapping of eukaryotic cells with scanning dielectric microscopy.
Collapse
Affiliation(s)
- Martí Checa
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Ruben Millan-Solsona
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
| | - Adrianna Glinkowska Mares
- Nanoscopy for Nanomedicine Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Silvia Pujals
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
- Nanoscopy for Nanomedicine Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
| | - Gabriel Gomila
- Nanoscale Bioelectrical Characterization Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri i Reixac 11-15, Barcelona, 08028, Spain
- Departament d'Enginyeria Electrònica i Biomèdica, Universitat de Barcelona, Carrer Martí i Franquès 1, Barcelona, 08028, Spain
| |
Collapse
|
10
|
Lloyd-Lewis B. Multidimensional Imaging of Mammary Gland Development: A Window Into Breast Form and Function. Front Cell Dev Biol 2020; 8:203. [PMID: 32296702 PMCID: PMC7138012 DOI: 10.3389/fcell.2020.00203] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/09/2020] [Indexed: 12/14/2022] Open
Abstract
An in-depth appreciation of organ form and function relies on the ability to image intact tissues across multiple scales. Difficulties associated with imaging deep within organs, however, can preclude high-resolution multidimensional imaging of live and fixed tissues. This is particularly challenging in the mammary gland, where the epithelium lies deeply encased within a stromal matrix. Recent advances in deep-tissue and live imaging methodologies are increasingly facilitating the visualization of complex cellular structures within their native environment. Alongside, refinements in optical tissue clearing and immunostaining methods are enabling 3D fluorescence imaging of whole organs at unprecedented resolutions. Collectively, these methods are illuminating the dynamic biological processes underlying tissue morphogenesis, homeostasis, and disease. This review provides a snapshot of the current and state-of-the-art multidimensional imaging techniques applied to the postnatal mammary gland, illustrating how these approaches have revealed important new insights into mammary gland ductal development and lactation. Continual evolution of multidimensional image acquisition and analysis methods will undoubtedly offer further insights into mammary gland biology that promises to shed new light on the perturbations leading to breast cancer.
Collapse
Affiliation(s)
- Bethan Lloyd-Lewis
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
11
|
Perrin L, Bayarmagnai B, Gligorijevic B. Frontiers in Intravital Multiphoton Microscopy of Cancer. Cancer Rep (Hoboken) 2020; 3:e1192. [PMID: 32368722 PMCID: PMC7197974 DOI: 10.1002/cnr2.1192] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/12/2019] [Accepted: 03/21/2019] [Indexed: 12/23/2022] Open
Abstract
Background Cancer is a highly complex disease which involves the co-operation of tumor cells with multiple types of host cells and the extracellular matrix. Cancer studies which rely solely on static measurements of individual cell types are insufficient to dissect this complexity. In the last two decades, intravital microscopy has established itself as a powerful technique that can significantly improve our understanding of cancer by revealing the dynamic interactions governing cancer initiation, progression and treatment effects, in living animals. This review focuses on intravital multiphoton microscopy (IV-MPM) applications in mouse models of cancer. Recent Findings IV-MPM studies have already enabled a deeper understanding of the complex events occurring in cancer, at the molecular, cellular and tissue levels. Multiple cells types, present in different tissues, influence cancer cell behavior via activation of distinct signaling pathways. As a result, the boundaries in the field of IV-MPM are continuously being pushed to provide an integrated comprehension of cancer. We propose that optics, informatics and cancer (cell) biology are co-evolving as a new field. We have identified four emerging themes in this new field. First, new microscopy systems and image processing algorithms are enabling the simultaneous identification of multiple interactions between the tumor cells and the components of the tumor microenvironment. Second, techniques from molecular biology are being exploited to visualize subcellular structures and protein activities within individual cells of interest, and relate those to phenotypic decisions, opening the door for "in vivo cell biology". Third, combining IV-MPM with additional imaging modalities, or omics studies, holds promise for linking the cell phenotype to its genotype, metabolic state or tissue location. Finally, the clinical use of IV-MPM for analyzing efficacy of anti-cancer treatments is steadily growing, suggesting a future role of IV-MPM for personalized medicine. Conclusion IV-MPM has revolutionized visualization of tumor-microenvironment interactions in real time. Moving forward, incorporation of novel optics, automated image processing, and omics technologies, in the study of cancer biology, will not only advance our understanding of the underlying complexities but will also leverage the unique aspects of IV-MPM for clinical use.
Collapse
Affiliation(s)
- Louisiane Perrin
- Department of BioengineeringTemple UniversityPhiladelphiaPennsylvania
| | | | - Bojana Gligorijevic
- Department of BioengineeringTemple UniversityPhiladelphiaPennsylvania
- Fox Chase Cancer CenterCancer Biology ProgramPhiladelphiaPennsylvania
| |
Collapse
|
12
|
Kim J, Bixel MG. Intravital Multiphoton Imaging of the Bone and Bone Marrow Environment. Cytometry A 2019; 97:496-503. [DOI: 10.1002/cyto.a.23937] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 12/11/2022]
Affiliation(s)
- JungMo Kim
- Department of Tissue MorphogenesisMax Planck Institute for Molecular Biomedicine D‐48149 Münster Germany
| | - Maria Gabriele Bixel
- Department of Tissue MorphogenesisMax Planck Institute for Molecular Biomedicine D‐48149 Münster Germany
| |
Collapse
|
13
|
Zheng Z, Li D, Liu Z, Peng HQ, Sung HHY, Kwok RTK, Williams ID, Lam JWY, Qian J, Tang BZ. Aggregation-Induced Nonlinear Optical Effects of AIEgen Nanocrystals for Ultradeep In Vivo Bioimaging. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1904799. [PMID: 31523871 DOI: 10.1002/adma.201904799] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/23/2019] [Indexed: 05/22/2023]
Abstract
Nonlinear optical microscopy has become a powerful tool in bioimaging research due to its unique capabilities of deep optical sectioning, high-spatial-resolution imaging, and 3D reconstruction of biological specimens. Developing organic fluorescent probes with strong nonlinear optical effects, in particular third-harmonic generation (THG), is promising for exploiting nonlinear microscopic imaging for biomedical applications. Herein, a simple method for preparing organic nanocrystals based on an aggregation-induced emission (AIE) luminogen (DCCN) with bright near-infrared emission is successfully demonstrated. Aggregation-induced nonlinear optical effects, including two-photon fluorescence (2PF), three-photon fluorescence (3PF), and THG, of DCCN are observed in nanoparticles, especially for crystalline nanoparticles. The nanocrystals of DCCN are successfully applied for 2PF microscopy at 1040 nm NIR-II excitation and THG microscopy at 1560 nm NIR-II excitation, respectively, to reconstruct the 3D vasculature of the mouse cerebral vasculature. Impressively, the THG microscopy provides much higher spatial resolution and brightness than the 2PF microscopy and can visualize small vessels with diameters of ≈2.7 µm at the deepest depth of 800 µm in a mouse brain. Thus, this is expected to inspire new insights into the development of advanced AIE materials with multiple nonlinearity, in particular THG, for multimodal nonlinear optical microscopy.
Collapse
Affiliation(s)
- Zheng Zheng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Dongyu Li
- State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Zhiyang Liu
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hui-Qing Peng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Herman H Y Sung
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ryan T K Kwok
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ian D Williams
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jacky W Y Lam
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jun Qian
- State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ben Zhong Tang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Institute of Molecular Functional Materials, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
- HKUST-Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park, Nanshan, Shenzhen, 518057, China
- Center for Aggregation-Induced Emission, SCUT-HKUST Joint Research Institute, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| |
Collapse
|
14
|
Liu C, Cabahug-Zuckerman P, Stubbs C, Pendola M, Cai C, Mann KA, Castillo AB. Mechanical Loading Promotes the Expansion of Primitive Osteoprogenitors and Organizes Matrix and Vascular Morphology in Long Bone Defects. J Bone Miner Res 2019; 34:896-910. [PMID: 30645780 PMCID: PMC8263903 DOI: 10.1002/jbmr.3668] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 12/17/2018] [Accepted: 01/07/2019] [Indexed: 12/18/2022]
Abstract
Elucidating the effects of mechanical stimulation on bone repair is crucial for optimization of the healing process. Specifically, the regulatory role that mechanical loading exerts on the osteogenic stem cell pool and vascular morphology during healing is incompletely understood. Because dynamic loading has been shown to enhance osteogenesis and repair, we hypothesized that loading induces the expansion of the osteoprogenitor cell population within a healing bone defect, leading to an increased presence of osteogenic cells. We further hypothesized that loading during the repair process regulates vascular and collagen matrix morphology and spatial interactions between vessels and osteogenic cells. To address these hypotheses, we used a mechanobiological bone repair model, which produces a consistent and reproducible intramembranous repair response confined in time and space. Bilateral tibial defects were created in adult C57BL/6 mice, which were subjected to axial compressive dynamic loading either during the early cellular invasion phase on postsurgical days (PSDs) 2 to 5 or during the matrix deposition phase on PSD 5 to 8. Confocal and two-photon microscopy was used to generate high-resolution three-dimensional (3D) renderings of longitudinal thick sections of the defect on PSD 10. Endomucin (EMCN)-positive vessels, Paired related homeobox 1 (Prrx1+) stem cell antigen-1 positive (Sca-1+) primitive osteoprogenitors (OPCs), and osterix positive (Osx+) preosteoblasts were visualized and quantified using deep tissue immunohistochemistry. New bone matrix was visualized with second harmonic generation autofluorescence of collagen fibers. We found that mechanical loading during the matrix deposition phase (PSD 5 to 8) increased vessel volume and number, and aligned vessels and collagen fibers to the load-bearing direction of bone. Furthermore, loading led to a significant increase in the proliferation and number of Prrx1+ Sca-1+ primitive OPCs, but not Osx+ preosteoblasts within the defect. Together, these data illustrate the adaptation of both collagen matrix and vascular morphology to better withstand mechanical load during bone repair, and that the mechanoresponsive cell population consists of the primitive osteogenic progenitors. © 2019 American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Chao Liu
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 10010
- Department of Orthopedic Surgery, School of Medicine, New York University, New York, NY 10010
- Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
| | - Pamela Cabahug-Zuckerman
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 10010
- Department of Orthopedic Surgery, School of Medicine, New York University, New York, NY 10010
| | - Christopher Stubbs
- Department of Mechanical Engineering, New York University, New York, NY 10010
| | - Martin Pendola
- Department of Orthopedic Surgery, School of Medicine, New York University, New York, NY 10010
| | - Cinyee Cai
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 10010
| | - Kenneth A. Mann
- Department of Orthopedic Surgery, Upstate Medical University, New York, NY 13210
| | - Alesha B. Castillo
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY 10010
- Department of Orthopedic Surgery, School of Medicine, New York University, New York, NY 10010
- Veterans Affairs New York Harbor Healthcare System, New York, NY 10010
| |
Collapse
|
15
|
Wu Q, Kumar N, Velagala V, Zartman JJ. Tools to reverse-engineer multicellular systems: case studies using the fruit fly. J Biol Eng 2019; 13:33. [PMID: 31049075 PMCID: PMC6480878 DOI: 10.1186/s13036-019-0161-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/07/2019] [Indexed: 01/08/2023] Open
Abstract
Reverse-engineering how complex multicellular systems develop and function is a grand challenge for systems bioengineers. This challenge has motivated the creation of a suite of bioengineering tools to develop increasingly quantitative descriptions of multicellular systems. Here, we survey a selection of these tools including microfluidic devices, imaging and computer vision techniques. We provide a selected overview of the emerging cross-talk between engineering methods and quantitative investigations within developmental biology. In particular, the review highlights selected recent examples from the Drosophila system, an excellent platform for understanding the interplay between genetics and biophysics. In sum, the integrative approaches that combine multiple advances in these fields are increasingly necessary to enable a deeper understanding of how to analyze both natural and synthetic multicellular systems.
Collapse
Affiliation(s)
- Qinfeng Wu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Nilay Kumar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Vijay Velagala
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Jeremiah J. Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556 USA
| |
Collapse
|
16
|
Hindelang B, Aguirre J, Schwarz M, Berezhnoi A, Eyerich K, Ntziachristos V, Biedermann T, Darsow U. Non-invasive imaging in dermatology and the unique potential of raster-scan optoacoustic mesoscopy. J Eur Acad Dermatol Venereol 2019; 33:1051-1061. [PMID: 30422337 PMCID: PMC6563473 DOI: 10.1111/jdv.15342] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/18/2018] [Indexed: 12/25/2022]
Abstract
In recent years, several non‐invasive imaging methods have been introduced to facilitate diagnostics and therapy monitoring in dermatology. The microscopic imaging methods are restricted in their penetration depth, while the mesoscopic methods probe deeper but provide only morphological, not functional, information. ‘Raster‐scan optoacoustic mesoscopy’ (RSOM), an emerging new imaging technique, combines deep penetration with contrast based on light absorption, which provides morphological, molecular and functional information. Here, we compare the capabilities and limitations of currently available dermatological imaging methods and highlight the principles and unique abilities of RSOM. We illustrate the clinical potential of RSOM, in particular for non‐invasive diagnosis and monitoring of inflammatory and oncological skin diseases.
Collapse
Affiliation(s)
- B Hindelang
- Department of Dermatology and Allergy, Technische Universität München, Munich, Germany.,Chair of Biological Imaging, Technische Universität München, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - J Aguirre
- Chair of Biological Imaging, Technische Universität München, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - M Schwarz
- Chair of Biological Imaging, Technische Universität München, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany.,iThera Medical GmbH, Munich, Germany
| | - A Berezhnoi
- Chair of Biological Imaging, Technische Universität München, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - K Eyerich
- Department of Dermatology and Allergy, Technische Universität München, Munich, Germany
| | - V Ntziachristos
- Chair of Biological Imaging, Technische Universität München, Munich, Germany.,Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - T Biedermann
- Department of Dermatology and Allergy, Technische Universität München, Munich, Germany
| | - U Darsow
- Department of Dermatology and Allergy, Technische Universität München, Munich, Germany
| |
Collapse
|
17
|
Toolbox for In Vivo Imaging of Host-Parasite Interactions at Multiple Scales. Trends Parasitol 2019; 35:193-212. [PMID: 30745251 DOI: 10.1016/j.pt.2019.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/04/2019] [Accepted: 01/04/2019] [Indexed: 12/19/2022]
Abstract
Animal models have for long been pivotal for parasitology research. Over the last few years, techniques such as intravital, optoacoustic and magnetic resonance imaging, optical projection tomography, and selective plane illumination microscopy developed promising potential for gaining insights into host-pathogen interactions by allowing different visualization forms in vivo and ex vivo. Advances including increased resolution, penetration depth, and acquisition speed, together with more complex image analysis methods, facilitate tackling biological problems previously impossible to study and/or quantify. Here we discuss advances and challenges in the in vivo imaging toolbox, which hold promising potential for the field of parasitology.
Collapse
|
18
|
Verstraete C, Mouchet SR, Verbiest T, Kolaric B. Linear and nonlinear optical effects in biophotonic structures using classical and nonclassical light. JOURNAL OF BIOPHOTONICS 2019; 12:e201800262. [PMID: 30288959 DOI: 10.1002/jbio.201800262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/02/2018] [Indexed: 06/08/2023]
Abstract
In this perspective article, we review the optical study of different biophotonic geometries and biological structures using classical light in linear and nonlinear regime, especially highlighting the link between these morphologies and modern biomedical research. Additionally, the importance of nonlinear optical study in biological research, beyond traditional cell imaging is also highlighted and described. Finally, we present a short introduction regarding nonclassical light and describe the new future perspective of quantum optical study in biology, revealing the link between quantum realm and biological research.
Collapse
Affiliation(s)
- Charlotte Verstraete
- Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Heverlee, Belgium
| | - Sébastien R Mouchet
- School of Physics, University of Exeter, Exeter, UK
- Department of Physics & Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium
| | - Thierry Verbiest
- Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Heverlee, Belgium
| | - Branko Kolaric
- Micro- and Nanophotonic Materials Group, University of Mons, Mons, Belgium
- Center for Photonics, Institute of Physics, University of Belgrade, Belgrade, Serbia
- Old World Labs, Virginia Beach, VA
| |
Collapse
|
19
|
Visualizing Viral Infection In Vivo by Multi-Photon Intravital Microscopy. Viruses 2018; 10:v10060337. [PMID: 29925766 PMCID: PMC6024644 DOI: 10.3390/v10060337] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/12/2018] [Accepted: 06/19/2018] [Indexed: 12/11/2022] Open
Abstract
Viral pathogens have adapted to the host organism to exploit the cellular machinery for virus replication and to modulate the host cells for efficient systemic dissemination and immune evasion. Much of our knowledge of the effects that virus infections have on cells originates from in vitro imaging studies using experimental culture systems consisting of cell lines and primary cells. Recently, intravital microscopy using multi-photon excitation of fluorophores has been applied to observe virus dissemination and pathogenesis in real-time under physiological conditions in living organisms. Critical steps during viral infection and pathogenesis could be studied by direct visualization of fluorescent virus particles, virus-infected cells, and the immune response to viral infection. In this review, I summarize the latest research on in vivo studies of viral infections using multi-photon intravital microscopy (MP-IVM). Initially, the underlying principle of multi-photon microscopy is introduced and experimental challenges during microsurgical animal preparation and fluorescent labeling strategies for intravital imaging are discussed. I will further highlight recent studies that combine MP-IVM with optogenetic tools and transcriptional analysis as a powerful approach to extend the significance of in vivo imaging studies of viral pathogens.
Collapse
|
20
|
Kang YG, Jang H, Yang TD, Notbohm J, Choi Y, Park Y, Kim BM. Quantification of focal adhesion dynamics of cell movement based on cell-induced collagen matrix deformation using second-harmonic generation microscopy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-8. [PMID: 29886577 DOI: 10.1117/1.jbo.23.6.065001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/14/2018] [Indexed: 06/08/2023]
Abstract
Mechanical interactions of living cells with the surrounding environment via focal adhesion (FA) in three dimensions (3-D) play a key role in dynamic biological events, such as tissue regeneration, wound healing, and cancer invasion. Recently, several methods for observing 3-D cell-extracellular matrix (ECM) interactions have been reported, lacking solid and quantitative analysis on the dynamics of the physical interaction between the cell and the ECM. We measured the submicron displacements of ECM deformation in 3-D due to protrusion-retraction dynamics during cell migration, using second-harmonic generation without labeling the matrix structures. We then quantitatively analyzed the mechanical deformation between the ECM and the cells based on spatiotemporal volumetric correlations. The greatest deformations within the collagen matrix were found to occur at sites of colocalization of the FA site-related proteins vinculin and actin, which confirms that FA sites play a critical role in living cells within the ECM as a point for adhesion, traction, and migration. We believe that this modality can be used in studies of cell-ECM interaction during angiogenesis, wound healing, and metastasis.
Collapse
Affiliation(s)
- Yong Guk Kang
- Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
| | - Hwanseok Jang
- Korea University Medical Center, Department of Biomedical Science, College of Medicine, Seoul, Republic of Korea
| | - Taeseok Daniel Yang
- Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
| | - Jacob Notbohm
- University of Wisconsin-Madison, Department of Engineering Physics, Madison, Wisconsin, United States
| | - Youngwoon Choi
- Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
| | - Yongdoo Park
- Korea University Medical Center, Department of Biomedical Science, College of Medicine, Seoul, Republic of Korea
| | - Beop-Min Kim
- Korea University, Department of Bio-convergence Engineering, Seoul, Republic of Korea
| |
Collapse
|
21
|
Sun TY, Haberman AM, Greco V. Preclinical Advances with Multiphoton Microscopy in Live Imaging of Skin Cancers. J Invest Dermatol 2016; 137:282-287. [PMID: 27847119 DOI: 10.1016/j.jid.2016.08.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/09/2016] [Accepted: 08/24/2016] [Indexed: 01/13/2023]
Abstract
Conventional, static analyses have historically been the bedrock and tool of choice for the study of skin cancers. Over the past several years, in vivo imaging of tumors using multiphoton microscopy has emerged as a powerful preclinical tool for revealing detailed cellular behaviors from the earliest moments of tumor development to the final steps of metastasis. Multiphoton microscopy allows for deep tissue penetration with relatively minor phototoxicity, rendering it an effective tool for the long-term observation of tumor evolution. This review highlights some of the recent preclinical insights gained using multiphoton microscopy and suggests future advances that could enhance its power in revealing the mysteries of skin tumor biology.
Collapse
Affiliation(s)
- Thomas Yang Sun
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA.
| | - Ann M Haberman
- Departments of Immunobiology and Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Valentina Greco
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA; Departments of Dermatology and Cell Biology, Yale Stem Cell Center, Yale Cancer Center, Yale School of Medicine, New Haven, Connecticut, USA.
| |
Collapse
|
22
|
Label-Free Imaging of Umbilical Cord Tissue Morphology and Explant-Derived Cells. Stem Cells Int 2016; 2016:5457132. [PMID: 27746820 PMCID: PMC5056264 DOI: 10.1155/2016/5457132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 07/28/2016] [Accepted: 07/31/2016] [Indexed: 01/08/2023] Open
Abstract
In situ detection of MSCs remains difficult and warrants additional methods to aid with their characterization in vivo. Two-photon confocal laser scanning microscopy (TPM) and second harmonic generation (SHG) could fill this gap. Both techniques enable the detection of cells and extracellular structures, based on intrinsic properties of the specific tissue and intracellular molecules under optical irradiation. TPM imaging and SHG imaging have been used for label-free monitoring of stem cells differentiation, assessment of their behavior in biocompatible scaffolds, and even cell tracking in vivo. In this study, we show that TPM and SHG can accurately depict the umbilical cord architecture and visualize individual cells both in situ and during culture initiation, without the use of exogenously applied labels. In combination with nuclear DNA staining, we observed a variance in fluorescent intensity in the vessel walls. In addition, antibody staining showed differences in Oct4, αSMA, vimentin, and ALDH1A1 expression in situ, indicating functional differences among the umbilical cord cell populations. In future research, marker-free imaging can be of great added value to the current antigen-based staining methods for describing tissue structures and for the identification of progenitor cells in their tissue of origin.
Collapse
|
23
|
Doyle AD. Generation of 3D Collagen Gels with Controlled Diverse Architectures. ACTA ACUST UNITED AC 2016; 72:10.20.1-10.20.16. [PMID: 27580704 DOI: 10.1002/cpcb.9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Rat tail collagen solutions have been used as polymerizable in vitro three dimensional (3D) extracellular matrix (ECM) gels for single and collective cell migration assays as well as spheroid formation. Factors such as ECM concentration, pH, ionic concentration, and temperature can alter collagen polymerization and ECM architecture. This unit describes how to generate 3D collagen gels that have distinct architectures ranging from a highly reticular meshwork of short thin fibrils with small pores to a loose matrix consisting of stiff, parallel-bundled long fibrils by changing collagen polymerization temperature. This permits analysis of 3D cell migration in different ECM architectures found in vivo while maintaining a similar ECM concentration. Also included are collagen labeling techniques helpful for ECM visualization during live fluorescence imaging. © 2016 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Andrew D Doyle
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda Maryland
| |
Collapse
|
24
|
McArdle S, Mikulski Z, Ley K. Live cell imaging to understand monocyte, macrophage, and dendritic cell function in atherosclerosis. J Exp Med 2016; 213:1117-31. [PMID: 27270892 PMCID: PMC4925021 DOI: 10.1084/jem.20151885] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/28/2016] [Indexed: 02/06/2023] Open
Abstract
Ley et al. provide a review of the technology and accomplishments of dynamic imaging of myeloid cells in atherosclerosis. Intravital imaging is an invaluable tool for understanding the function of cells in healthy and diseased tissues. It provides a window into dynamic processes that cannot be studied by other techniques. This review will cover the benefits and limitations of various techniques for labeling and imaging myeloid cells, with a special focus on imaging cells in atherosclerotic arteries. Although intravital imaging is a powerful tool for understanding cell function, it alone does not provide a complete picture of the cell. Other techniques, such as flow cytometry and transcriptomics, must be combined with intravital imaging to fully understand a cell's phenotype, lineage, and function.
Collapse
Affiliation(s)
- Sara McArdle
- Division of Inflammation Biology and Microscopy Core, La Jolla Institute of Allergy and Immunology, La Jolla, CA 92037
| | - Zbigniew Mikulski
- Division of Inflammation Biology and Microscopy Core, La Jolla Institute of Allergy and Immunology, La Jolla, CA 92037
| | - Klaus Ley
- Division of Inflammation Biology and Microscopy Core, La Jolla Institute of Allergy and Immunology, La Jolla, CA 92037
| |
Collapse
|
25
|
Jain R, Tikoo S, Weninger W. Recent advances in microscopic techniques for visualizing leukocytes in vivo. F1000Res 2016; 5:F1000 Faculty Rev-915. [PMID: 27239292 PMCID: PMC4874443 DOI: 10.12688/f1000research.8127.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/12/2016] [Indexed: 12/26/2022] Open
Abstract
Leukocytes are inherently motile and interactive cells. Recent advances in intravital microscopy approaches have enabled a new vista of their behavior within intact tissues in real time. This brief review summarizes the developments enabling the tracking of immune responses in vivo.
Collapse
Affiliation(s)
- Rohit Jain
- Immune Imaging Program, The Centenary Institute, University of Sydney, Newtown, NSW 2042, Australia; Discipline of Dermatology, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - Shweta Tikoo
- Immune Imaging Program, The Centenary Institute, University of Sydney, Newtown, NSW 2042, Australia; Discipline of Dermatology, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - Wolfgang Weninger
- Immune Imaging Program, The Centenary Institute, University of Sydney, Newtown, NSW 2042, Australia; Discipline of Dermatology, Sydney Medical School, University of Sydney, NSW 2006, Australia; Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
| |
Collapse
|
26
|
Lagoutte E, Villeneuve C, Lafanechère L, Wells CM, Jones GE, Chavrier P, Rossé C. LIMK Regulates Tumor-Cell Invasion and Matrix Degradation Through Tyrosine Phosphorylation of MT1-MMP. Sci Rep 2016; 6:24925. [PMID: 27116935 PMCID: PMC4847008 DOI: 10.1038/srep24925] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 04/06/2016] [Indexed: 12/24/2022] Open
Abstract
During their metastatic spread, cancer cells need to remodel the extracellular matrix in order to migrate through stromal compartments adjacent to the primary tumor. Dissemination of breast carcinoma cells is mediated by membrane type 1-matrix metalloproteinase (MT1-MMP/MMP14), the main invadopodial matrix degradative component. Here, we identify MT1-MMP as a novel interacting partner of dual-specificity LIM Kinase-1 and -2 (LIMK1/2), and provide several evidence for phosphorylation of tyrosine Y573 in the cytoplasmic domain of MT1-MMP by LIMK. Phosphorylation of Y573 influences association of F-actin binding protein cortactin to MT1-MMP-positive endosomes and invadopodia formation and matrix degradation. Moreover, we show that LIMK1 regulates cortactin association to MT1-MMP-positive endosomes, while LIMK2 controls invadopodia-associated cortactin. In turn, LIMK1 and LIMK2 are required for MT1-MMP-dependent matrix degradation and cell invasion in a three-dimensional type I collagen environment. This novel link between LIMK1/2 and MT1-MMP may have important consequences for therapeutic control of breast cancer cell invasion.
Collapse
Affiliation(s)
- Emilie Lagoutte
- Institut Curie, PSL Research University, CNRS UMR 144, Membrane and Cytoskeleton Dynamics, 75248 cedex 05, Paris, France
| | - Clémentine Villeneuve
- Institut Curie, PSL Research University, CNRS UMR 144, Membrane and Cytoskeleton Dynamics, 75248 cedex 05, Paris, France
| | - Laurence Lafanechère
- Univ. Grenoble Alpes, INSERM U823, Institut Albert Bonniot, CRI, Team 3 "Polarity, Development and Cancer", F-38000 Grenoble France
| | - Claire M Wells
- Division of Cancer Studies, King's College London, London, United Kingdom
| | - Gareth E Jones
- Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Philippe Chavrier
- Institut Curie, PSL Research University, CNRS UMR 144, Membrane and Cytoskeleton Dynamics, 75248 cedex 05, Paris, France
| | - Carine Rossé
- Institut Curie, PSL Research University, CNRS UMR 144, Membrane and Cytoskeleton Dynamics, 75248 cedex 05, Paris, France
| |
Collapse
|
27
|
Schuh C, Haenni D, Craigie E, Ziegler U, Weber B, Devuyst O, Hall AM. Long wavelength multiphoton excitation is advantageous for intravital kidney imaging. Kidney Int 2016; 89:712-9. [DOI: 10.1038/ki.2015.323] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/14/2015] [Accepted: 09/03/2015] [Indexed: 11/09/2022]
|
28
|
Abstract
Recently we have explored and developed approaches imaging using confocal/two-photon microscopy, which enables simultaneous high-resolution assessment of specifically fluorescently marked cells in conjunction with structural components of the tissues visualized via harmonic generated signals. This approach uses commercially available confocal and two-photon laser microscope and automated user-interactive image analysis methods based on commercially available software packages allowing easy implementation in usual microscopy facilities.
Collapse
Affiliation(s)
- Daniela Malide
- Light Microscopy Core Facility, National Heart, Lung, and Blood Institute, National Institute of Health, Building 10, Room 6 N-309, 10 Center Drive, Bethesda, MD, 20892, USA.
| |
Collapse
|
29
|
Abstract
Much progress in understanding cell migration has been determined by using classic two-dimensional (2D) tissue culture platforms. However, increasingly, it is appreciated that certain properties of cell migration
in vivo are not represented by strictly 2D assays. There is much interest in creating relevant three-dimensional (3D) culture environments and engineered platforms to better represent features of the extracellular matrix and stromal microenvironment that are not captured in 2D platforms. Important to this goal is a solid understanding of the features of the extracellular matrix—composition, stiffness, topography, and alignment—in different tissues and disease states and the development of means to capture these features
Collapse
Affiliation(s)
- Patricia Keely
- Department of Cell and Regenerative Biology, UW Carbone Cancer Center, UW School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Amrinder Nain
- 2Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, USA
| |
Collapse
|
30
|
Unleashing Optics and Optoacoustics for Developmental Biology. Trends Biotechnol 2015; 33:679-691. [PMID: 26435161 DOI: 10.1016/j.tibtech.2015.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 08/11/2015] [Accepted: 08/18/2015] [Indexed: 01/23/2023]
Abstract
The past decade marked an optical revolution in biology: an unprecedented number of optical techniques were developed and adopted for biological exploration, demonstrating increasing interest in optical imaging and in vivo interrogations. Optical methods have become faster and have reached nanoscale resolution, and are now complemented by optoacoustic (photoacoustic) methods capable of imaging whole specimens in vivo. Never before were so many optical imaging barriers broken in such a short time-frame: with new approaches to optical microscopy and mesoscopy came an increased ability to image biology at unprecedented speed, resolution, and depth. This review covers the most relevant techniques for imaging in developmental biology, and offers an outlook on the next steps for these technologies and their applications.
Collapse
|
31
|
Peralta L, Mourier E, Richard C, Charpigny G, Larcher T, Aït-Belkacem D, Balla NK, Brasselet S, Tanter M, Muller M, Chavatte-Palmer P. In Vivo Evaluation of Cervical Stiffness Evolution during Induced Ripening Using Shear Wave Elastography, Histology and 2 Photon Excitation Microscopy: Insight from an Animal Model. PLoS One 2015; 10:e0133377. [PMID: 26317774 PMCID: PMC4552804 DOI: 10.1371/journal.pone.0133377] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 06/26/2015] [Indexed: 11/18/2022] Open
Abstract
Prematurity affects 11% of the births and is the main cause of infant mortality. On the opposite case, the failure of induction of parturition in the case of delayed spontaneous birth is associated with fetal suffering. Both conditions are associated with precocious and/or delayed cervical ripening. Quantitative and objective information about the temporal evolution of the cervical ripening may provide a complementary method to identify cases at risk of preterm delivery and to assess the likelihood of successful induction of labour. In this study, the cervical stiffness was measured in vivo in pregnant sheep by using Shear Wave Elastography (SWE). This technique assesses the stiffness of tissue through the measurement of shear waves speed (SWS). In the present study, 9 pregnant ewes were used. Cervical ripening was induced at 127 days of pregnancy (term: 145 days) by dexamethasone injection in 5 animals, while 4 animals were used as control. Elastographic images of the cervix were obtained by two independent operators every 4 hours during 24 hours after injection to monitor the cervical maturation induced by the dexamethasone. Based on the measurements of SWS during vaginal ultrasound examination, the stiffness in the second ring of the cervix was quantified over a circular region of interest of 5 mm diameter. SWS was found to decrease significantly in the first 4-8 hours after dexamethasone compared to controls, which was associated with cervical ripening induced by dexamethasone (from 1.779 m/s ± 0.548 m/s, p < 0.0005, to 1.291 m/s ± 0.516 m/s, p < 0.000). Consequently a drop in the cervical elasticity was quantified too (from 9.5 kPa ± 0.9 kPa, p < 0.0005, to 5.0 kPa ± 0.8 kPa, p < 0.000). Moreover, SWE measurements were highly reproducible between both operators at all times. Cervical ripening induced by dexamethasone was confirmed by the significant increase in maternal plasma Prostaglandin E2 (PGE2), as evidenced by the assay of its metabolite PGEM. Histological analyses and two-photon excitation microscopy, combining both Second Harmonic Generation (SHG) and Two-photon Fluorescence microscopy (2PF) contrasts, were used to investigate, at the microscopic scale, the structure of cervical tissue. Results show that both collagen and 2PF-active fibrillar structures could be closely related to the mechanical properties of cervical tissue that are perceptible in elastography. In conclusion, SWE may be a valuable method to objectively quantify the cervical stiffness and as a complementary diagnostic tool for preterm birth and for labour induction success.
Collapse
Affiliation(s)
- Laura Peralta
- Department of Structural Mechanics, University of Granada, Granada, Spain
| | - Eve Mourier
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy en Josas, France
- PremUp foundation, 75006 Paris, France
| | - Christophe Richard
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy en Josas, France
- PremUp foundation, 75006 Paris, France
| | - Gilles Charpigny
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy en Josas, France
| | | | - Dora Aït-Belkacem
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, 13013 Marseille, France
| | - Naveen K. Balla
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, 13013 Marseille, France
| | - Sophie Brasselet
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, 13013 Marseille, France
| | - Mickael Tanter
- Institut Langevin, ESPCI ParisTech, CNRS, Université Paris Diderot - Paris 7, Paris, France
| | - Marie Muller
- Institut Langevin, ESPCI ParisTech, CNRS, Université Paris Diderot - Paris 7, Paris, France
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Pascale Chavatte-Palmer
- INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy en Josas, France
- PremUp foundation, 75006 Paris, France
| |
Collapse
|
32
|
|
33
|
Bixel GM, Fretham SJB, Aschner M. High-Resolution Multi-Photon Imaging of Morphological Structures of Caenorhabditis elegans. ACTA ACUST UNITED AC 2015; 64:11.19.1-11. [PMID: 26344221 DOI: 10.1002/0471140856.tx1119s64] [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] [Indexed: 11/10/2022]
Abstract
In this protocol, we combine two-photon excitation fluorescence with nonlinear optical measurements to reconstruct the three-dimensional architecture of the pharyngeal region and the muscular system of the anterior and mid-body region of Caenorhabditis elegans (C. elegans). Femto-second laser pulses excite second-harmonic generation (SHG) and third-harmonic generation (THG) signals, which show detailed structural information regarding the organization of myofibrils that are arranged around the central pharynx region. The combination of two-photon excitation with SHG and THG imaging is a very powerful tool to study cell morphology, microarchitecture, and tissue arrangement in C. elegans.
Collapse
Affiliation(s)
- Gabriele M Bixel
- Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, and University of Muenster, Muenster, Germany
| | | | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
| |
Collapse
|
34
|
Sikora M, Scheiner D, Betschart C, Perucchini D, Mateos JM, di Natale A, Fink D, Maake C. Label-free, three-dimensional multiphoton microscopy of the connective tissue in the anterior vaginal wall. Int Urogynecol J 2014; 26:685-91. [PMID: 25421935 DOI: 10.1007/s00192-014-2571-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/04/2014] [Indexed: 11/27/2022]
Abstract
INTRODUCTION AND HYPOTHESIS Multiphoton microscopy (MPM) is a nonlinear, high-resolution laser scanning technique and a powerful approach for analyzing the spatial architecture within tissues. To demonstrate the potential of this technique for studying the extracellular matrix of the pelvic organs, we aimed to establish protocols for the detection of collagen and elastin in the vagina and to compare the MPM density of these fibers to fibers detected using standard histological methods. METHODS Samples of the anterior vaginal wall were obtained from nine patients undergoing a hysterectomy or cystocele repair. Samples were shock frozen, fixed with formaldehyde or Thiel's solution, or left untreated. Samples were imaged with MPM to quantify the amount of collagen and elastin via second harmonic generation and autofluorescence, respectively. In six patients, sample sections were also histologically stained and imaged with brightfield microscopy. The density of the fibers was quantified using the StereoInvestigator and Cavalieri software. RESULTS With MPM, collagen and elastin could be visualized to a depth of 100 μm, and no overlap of signals was detected. The different tissue processing protocols used did not result in significantly different fiber counts after MPM. MPM-based fiber quantifications are comparable to those based on conventional histological stains. However, MPM provided superior resolution, particularly of collagen fibers. CONCLUSIONS MPM is a robust, rapid, and label-free method that can be used to quantify the collagen and elastin content in thick specimens of the vagina. It is an excellent tool for future three-dimensional studies of the extracellular matrix in patients with pelvic organ prolapse.
Collapse
Affiliation(s)
- Michal Sikora
- Department of Gynecology, University Hospital Zurich, Frauenklinikstrasse 10, 8091, Zurich, Switzerland,
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Abstract
To comprehend the complexity of cancer, the biological characteristics acquired during the initiation and progression of tumours were classified as the 'hallmarks of cancer'. Intravital microscopy techniques have been developed to study individual cells that acquire these crucial traits, by visualizing tissues with cellular or subcellular resolution in living animals. In this Review, we highlight the latest intravital microscopy techniques that have been used in living animals (predominantly mice) to unravel fundamental and dynamic aspects of various hallmarks of cancer. In addition, we discuss the application of intravital microscopy techniques to cancer therapy, as well as limitations and future perspectives for these techniques.
Collapse
Affiliation(s)
- Saskia I J Ellenbroek
- Cancer Genomics Netherlands-Hubrecht Institute-KNAW & University Medical Centre Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Jacco van Rheenen
- Cancer Genomics Netherlands-Hubrecht Institute-KNAW & University Medical Centre Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| |
Collapse
|
36
|
Mathes SH, Ruffner H, Graf-Hausner U. The use of skin models in drug development. Adv Drug Deliv Rev 2014; 69-70:81-102. [PMID: 24378581 DOI: 10.1016/j.addr.2013.12.006] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 12/12/2022]
Abstract
Three dimensional (3D) tissue models of the human skin are probably the most developed and understood in vitro engineered constructs. The motivation to accomplish organotypic structures was driven by the clinics to enable transplantation of in vitro grown tissue substitutes and by the cosmetics industry as alternative test substrates in order to replace animal models. Today a huge variety of 3D human skin models exist, covering a multitude of scientific and/or technical demands. This review summarizes and discusses different approaches of skin model development and sets them into the context of drug development. Although human skin models have become indispensable for the cosmetics industry, they have not yet started their triumphal procession in pharmaceutical research and development. For drug development these tissue models may be of particular interest for a) systemically acting drugs applied on the skin, and b) drugs acting at the site of application in the case of skin diseases or disorders. Although quite a broad spectrum of models covering different aspects of the skin as a biologically acting surface exists, these are most often single stand-alone approaches. In order to enable the comprehensive application into drug development processes, the approaches have to be synchronized to allow a cross-over comparison. Besides the development of biological relevant models, other issues are not less important in the context of drug development: standardized production procedures, process automation, establishment of significant analytical methods, and data correlation. For the successful routine use of engineered human skin models in drug development, major requirements were defined. If these requirements can be accomplished in the next few years, human organotypic skin models will become indispensable for drug development, too.
Collapse
Affiliation(s)
- Stephanie H Mathes
- Institute of Chemistry and Biological Chemistry, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820 Waedenswil, Switzerland
| | - Heinz Ruffner
- Developmental and Molecular Pathways (DMP), Novartis Institutes for BioMedical Research (NIBR), Fabrikstrasse 22, 4056 Basel, Switzerland
| | - Ursula Graf-Hausner
- Institute of Chemistry and Biological Chemistry, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820 Waedenswil, Switzerland.
| |
Collapse
|
37
|
Steady-state and time-resolved spectroscopic studies of green-to-red photoconversion of fluorescent protein Dendra2. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
38
|
Claser C, Malleret B, Peng K, Bakocevic N, Gun SY, Russell B, Ng LG, Rénia L. Rodent Plasmodium-infected red blood cells: Imaging their fates and interactions within their hosts. Parasitol Int 2014; 63:187-94. [DOI: 10.1016/j.parint.2013.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 06/30/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
|
39
|
Abstract
During metastasis, cancer cells disseminate to other parts of the body by entering the bloodstream in a process that is called intravasation. They then extravasate at metastatic sites by attaching to endothelial cells that line blood vessels and crossing the vessel walls of tissues or organs. This Review describes how cancer cells cross the endothelial barrier during extravasation and how different receptors, signalling pathways and circulating cells such as leukocytes and platelets contribute to this process. Identification of the mechanisms that underlie cancer cell extravasation could lead to the development of new therapies to reduce metastasis.
Collapse
Affiliation(s)
- Nicolas Reymond
- 1] Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK. [2] Centre de Recherche de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique (CNRS) - UMR5237, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France. [3]
| | | | | |
Collapse
|
40
|
Miron-Mendoza M, Koppaka V, Zhou C, Petroll WM. Techniques for assessing 3-D cell-matrix mechanical interactions in vitro and in vivo. Exp Cell Res 2013; 319:2470-80. [PMID: 23819988 PMCID: PMC3826791 DOI: 10.1016/j.yexcr.2013.06.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/22/2013] [Accepted: 06/24/2013] [Indexed: 12/19/2022]
Abstract
Cellular interactions with extracellular matrices (ECM) through the application of mechanical forces mediate numerous biological processes including developmental morphogenesis, wound healing and cancer metastasis. They also play a key role in the cellular repopulation and/or remodeling of engineered tissues and organs. While 2-D studies can provide important insights into many aspects of cellular mechanobiology, cells reside within 3-D ECMs in vivo, and matrix structure and dimensionality have been shown to impact cell morphology, protein organization and mechanical behavior. Global measurements of cell-induced compaction of 3-D collagen matrices can provide important insights into the regulation of overall cell contractility by various cytokines and signaling pathways. However, to understand how the mechanics of cell spreading, migration, contraction and matrix remodeling are regulated at the molecular level, these processes must also be studied in individual cells. Here we review the evolution and application of techniques for imaging and assessing local cell-matrix mechanical interactions in 3-D culture models, tissue explants and living animals.
Collapse
Affiliation(s)
- Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Vindhya Koppaka
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Chengxin Zhou
- Graduate Program in Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX
| | - W. Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
- Graduate Program in Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX
| |
Collapse
|
41
|
Alexander S, Weigelin B, Winkler F, Friedl P. Preclinical intravital microscopy of the tumour-stroma interface: invasion, metastasis, and therapy response. Curr Opin Cell Biol 2013; 25:659-71. [PMID: 23896198 DOI: 10.1016/j.ceb.2013.07.001] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 01/10/2023]
Abstract
Key steps of cancer progression and therapy response depend upon interactions between cancer cells with the reactive tumour microenvironment. Intravital microscopy enables multi-modal and multi-scale monitoring of cancer progression as a dynamic step-wise process within anatomic and functional niches provided by the microenvironment. These niches deliver cell-derived and matrix-derived signals that enable cell subsets or single cancer cells to survive, migrate, grow, undergo dormancy, and escape immune surveillance. Beyond basic research, intravital microscopy has reached preclinical application to identify mechanisms of tumour-stroma interactions and outcome. We here summarise how n-dimensional 'dynamic histopathology' of tumours by intravital microscopy shapes mechanistic insight into cell-cell and cell-tissue interactions that underlie single-cell and collective cancer invasion, metastatic seeding at distant sites, immune evasion, and therapy responses.
Collapse
Affiliation(s)
- Stephanie Alexander
- David H. Koch Center for Applied Research of Genitourinary Cancers, Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | | | | | | |
Collapse
|
42
|
Weigelin B, Bakker GJ, Friedl P. Intravital third harmonic generation microscopy of collective melanoma cell invasion: Principles of interface guidance and microvesicle dynamics. INTRAVITAL 2012; 1:32-43. [PMID: 29607252 PMCID: PMC5858865 DOI: 10.4161/intv.21223] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 06/21/2012] [Indexed: 12/21/2022]
Abstract
Cancer cell invasion is an adaptive process based on cell-intrinsic properties to migrate individually or collectively, and their adaptation to encountered tissue structure acting as barrier or providing guidance. Whereas molecular and physical mechanisms of cancer invasion are well-studied in 3D in vitro models, their topographic relevance, classification and validation toward interstitial tissue organization in vivo remain incomplete. Using combined intravital third and second harmonic generation (THG, SHG), and three-channel fluorescence microscopy in live tumors, we here map B16F10 melanoma invasion into the dermis with up to 600 µm penetration depth and reconstruct both invasion mode and tissue tracks to establish invasion routes and outcome. B16F10 cells preferentially develop adaptive invasion patterns along preformed tracks of complex, multi-interface topography, combining single-cell and collective migration modes, without immediate anatomic tissue remodeling or destruction. The data suggest that the dimensionality (1D, 2D, 3D) of tissue interfaces determines the microanatomy exploited by invading tumor cells, emphasizing non-destructive migration along microchannels coupled to contact guidance as key invasion mechanisms. THG imaging further detected the presence and interstitial dynamics of tumor-associated microparticles with submicron resolution, revealing tumor-imposed conditioning of the microenvironment. These topographic findings establish combined THG, SHG and fluorescence microscopy in intravital tumor biology and provide a template for rational in vitro model development and context-dependent molecular classification of invasion modes and routes.
Collapse
Affiliation(s)
- Bettina Weigelin
- Department of Cell Biology; Radboud University Nijmegen Medical Centre; Nijmegen, The Netherlands
| | - Gert-Jan Bakker
- Department of Cell Biology; Radboud University Nijmegen Medical Centre; Nijmegen, The Netherlands
| | - Peter Friedl
- Department of Cell Biology; Radboud University Nijmegen Medical Centre; Nijmegen, The Netherlands.,David H. Koch Center for Applied Research of Genitourinary Cancers; Department of Genitourinary Medical Oncology; The University of Texas MD Anderson Cancer Center; Houston, TX USA
| |
Collapse
|
43
|
Petrie RJ, Gavara N, Chadwick RS, Yamada KM. Nonpolarized signaling reveals two distinct modes of 3D cell migration. ACTA ACUST UNITED AC 2012; 197:439-55. [PMID: 22547408 PMCID: PMC3341168 DOI: 10.1083/jcb.201201124] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The elastic behavior of the 3D extracellular matrix determines the relative polarization of intracellular signaling and whether cells migrate using lamellipodia or lobopodia. We search in this paper for context-specific modes of three-dimensional (3D) cell migration using imaging for phosphatidylinositol (3,4,5)-trisphosphate (PIP3) and active Rac1 and Cdc42 in primary fibroblasts migrating within different 3D environments. In 3D collagen, PIP3 and active Rac1 and Cdc42 were targeted to the leading edge, consistent with lamellipodia-based migration. In contrast, elongated cells migrating inside dermal explants and the cell-derived matrix (CDM) formed blunt, cylindrical protrusions, termed lobopodia, and Rac1, Cdc42, and PIP3 signaling was nonpolarized. Reducing RhoA, Rho-associated protein kinase (ROCK), or myosin II activity switched the cells to lamellipodia-based 3D migration. These modes of 3D migration were regulated by matrix physical properties. Specifically, experimentally modifying the elasticity of the CDM or collagen gels established that nonlinear elasticity supported lamellipodia-based migration, whereas linear elasticity switched cells to lobopodia-based migration. Thus, the relative polarization of intracellular signaling identifies two distinct modes of 3D cell migration governed intrinsically by RhoA, ROCK, and myosin II and extrinsically by the elastic behavior of the 3D extracellular matrix.
Collapse
Affiliation(s)
- Ryan J Petrie
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | |
Collapse
|
44
|
Yousefi S, Kehtarnavaz N, Gholipour A. Synthesis of cervical tissue second harmonic generation images using Markov random field modeling. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:6180-3. [PMID: 22255750 DOI: 10.1109/iembs.2011.6091526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper presents a statistical image modeling approach based on Markov random field to synthesize cervical tissue second harmonic generation (SHG) images. Binary images representing fiber and pore areas of the cervix tissue are first obtained from SHG images using an image processing pipeline consisting of noise removal, contrast enhancement and optimal thresholding. These binary images are modeled using a Markov random field whose parameters are estimated via the least squares method. The parameters are then used to synthesize fiber and pore areas of cervical tissue in the form of binary images. The effectiveness of the synthesis is demonstrated by reporting the classification outcome for two classes of cervical SHG images collected from mice at two different stages of normal pregnancy. The developed synthesis allows generation of realistic fiber and pore area binary images for cervical tissue studies.
Collapse
Affiliation(s)
- S Yousefi
- Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX, USA
| | | | | |
Collapse
|
45
|
Fluorescence Lifetime Microscopy of Tumor Cell Invasion, Drug Delivery, and Cytotoxicity. Methods Enzymol 2012; 504:109-25. [DOI: 10.1016/b978-0-12-391857-4.00005-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
46
|
Label-free 3D visualization of cellular and tissue structures in intact muscle with second and third harmonic generation microscopy. PLoS One 2011; 6:e28237. [PMID: 22140560 PMCID: PMC3225396 DOI: 10.1371/journal.pone.0028237] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 11/04/2011] [Indexed: 11/19/2022] Open
Abstract
Second and Third Harmonic Generation (SHG and THG) microscopy is based on optical effects which are induced by specific inherent physical properties of a specimen. As a multi-photon laser scanning approach which is not based on fluorescence it combines the advantages of a label-free technique with restriction of signal generation to the focal plane, thus allowing high resolution 3D reconstruction of image volumes without out-of-focus background several hundred micrometers deep into the tissue. While in mammalian soft tissues SHG is mostly restricted to collagen fibers and striated muscle myosin, THG is induced at a large variety of structures, since it is generated at interfaces such as refraction index changes within the focal volume of the excitation laser. Besides, colorants such as hemoglobin can cause resonance enhancement, leading to intense THG signals. We applied SHG and THG microscopy to murine (Mus musculus) muscles, an established model system for physiological research, to investigate their potential for label-free tissue imaging. In addition to collagen fibers and muscle fiber substructure, THG allowed us to visualize blood vessel walls and erythrocytes as well as white blood cells adhering to vessel walls, residing in or moving through the extravascular tissue. Moreover peripheral nerve fibers could be clearly identified. Structure down to the nuclear chromatin distribution was visualized in 3D and with more detail than obtainable by bright field microscopy. To our knowledge, most of these objects have not been visualized previously by THG or any label-free 3D approach. THG allows label-free microscopy with inherent optical sectioning and therefore may offer similar improvements compared to bright field microscopy as does confocal laser scanning microscopy compared to conventional fluorescence microscopy.
Collapse
|
47
|
Wolf K, Friedl P. Extracellular matrix determinants of proteolytic and non-proteolytic cell migration. Trends Cell Biol 2011; 21:736-44. [PMID: 22036198 DOI: 10.1016/j.tcb.2011.09.006] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 09/20/2011] [Accepted: 09/22/2011] [Indexed: 11/25/2022]
Abstract
Cell invasion into the 3D extracellular matrix (ECM) is a multistep biophysical process involved in inflammation, tissue repair, and metastatic cancer invasion. Migrating cells navigate through tissue structures of complex and often varying physicochemical properties, including molecular composition, porosity, alignment and stiffness, by adopting strategies that involve deformation of the cell and engagement of matrix-degrading proteases. We review how the ECM determines whether or not pericellular proteolysis is required for cell migration, ranging from protease-driven invasion and secondary tissue destruction, to non-proteolytic, non-destructive movement that solely depends on cell deformability and available tissue space. These concepts call for therapeutic targeting of proteases to prevent invasion-associated tissue destruction rather than the migration process per se.
Collapse
Affiliation(s)
- Katarina Wolf
- Department of Cell Biology, Nijmegen Center for Molecular Life Science, Radboud University Nijmegen, 6500 HB Nijmegen, The Netherlands.
| | | |
Collapse
|
48
|
Miller MJ, McDole JR, Newberry RD. Microanatomy of the intestinal lymphatic system. Ann N Y Acad Sci 2010; 1207 Suppl 1:E21-8. [PMID: 20961303 DOI: 10.1111/j.1749-6632.2010.05708.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The intestinal lymphatic system comprises two noncommunicating lymphatic networks: one containing the lacteals draining the villi and the connecting submucosal lymphatic network and one containing the lymphatics that drain the intestine muscular layer. These systems deliver lymph into a common network of collecting lymphatics originating near the mesenteric border. The intestinal lymphatic system serves vital functions in the regulation of tissue fluid homeostasis, immune surveillance, and the transport of nutrients; conversely, this system is affected by, and directly contributes to, disease processes within the intestine. Recent discoveries of specific lymphatic markers, factors promoting lymphangiogenesis, and factors selectively affecting the development of intestinal lymphatics, hold promise for unlocking the role of lymphatics in the pathogenesis of diseases affecting the intestine and for intestinal lymphatic selective therapies. Vital to progress in understanding how the intestinal lymphatic system functions is the integration of recent advances identifying molecular pathways for lymphatic growth and remodeling with advanced imaging modalities to observe lymphatic function and dysfunction in vivo.
Collapse
Affiliation(s)
- Mark J Miller
- Department of Pathology and Immunology, St. Louis, Missouri, USA
| | | | | |
Collapse
|
49
|
Mrass P, Petravic J, Davenport MP, Weninger W. Cell-autonomous and environmental contributions to the interstitial migration of T cells. Semin Immunopathol 2010; 32:257-74. [PMID: 20623124 PMCID: PMC2937148 DOI: 10.1007/s00281-010-0212-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 05/31/2010] [Indexed: 01/23/2023]
Abstract
A key to understanding the functioning of the immune system is to define the mechanisms that facilitate directed lymphocyte migration to and within tissues. The recent development of improved imaging technologies, most prominently multi-photon microscopy, has enabled the dynamic visualization of immune cells in real-time directly within intact tissues. Intravital imaging approaches have revealed high spontaneous migratory activity of T cells in secondary lymphoid organs and inflamed tissues. Experimental evidence points towards both environmental and cell-intrinsic cues involved in the regulation of lymphocyte motility in the interstitial space. Based on these data, several conceptually distinct models have been proposed in order to explain the coordination of lymphocyte migration both at the single cell and population level. These range from “stochastic” models, where chance is the major driving force, to “deterministic” models, where the architecture of the microenvironment dictates the migratory trajectory of cells. In this review, we focus on recent advances in understanding naïve and effector T cell migration in vivo. In addition, we discuss some of the contradictory experimental findings in the context of theoretical models of migrating leukocytes.
Collapse
Affiliation(s)
- Paulus Mrass
- The Centenary Institute, Locked Bag No. 6, Newtown, New South Wales 2042, Australia.
| | | | | | | |
Collapse
|
50
|
Rehberg M, Krombach F, Pohl U, Dietzel S. Signal improvement in multiphoton microscopy by reflection with simple mirrors near the sample. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:026017. [PMID: 20459262 DOI: 10.1117/1.3374337] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In conventional fluorescence or confocal microscopy, emitted light is generated not only in the focal plane but also above and below. The situation is different in multiphoton-induced fluorescence and multiphoton-induced higher harmonic generation. Here, restriction of signal generation to a single focal point permits that all emitted photons can contribute to image formation if collected, regardless of their path through the specimen. Often, the intensity of the emitted light is rather low in biological specimens. We present a method to significantly increase the fraction of photons collected by an epi (backward) detector by placing a simple mirror, an aluminum-coated coverslip, directly under the sample. Samples investigated include fluorescent test slides, collagen gels, and thin-layered, intact mouse skeletal muscles. Quantitative analysis revealed an intensity increase of second- and third-harmonic generated signal in skeletal muscle of nine- and sevenfold respectively, and of fluorescent signal in test slides of up to twofold. Our approach thus allows significant signal improvement also for situations were a forward detection is impossible, e.g., due to the anatomy of animals in intravital microscopy.
Collapse
Affiliation(s)
- Markus Rehberg
- Ludwig-Maximilians-Universitat Munchen, Walter-Brendel-Zentrum fur Experimentelle Medizin, Marchioninistrasse 27, Munchen, D-81377 Germany
| | | | | | | |
Collapse
|