1
|
Serra Lleti JM, Steyer AM, Schieber NL, Neumann B, Tischer C, Hilsenstein V, Holtstrom M, Unrau D, Kirmse R, Lucocq JM, Pepperkok R, Schwab Y. CLEMSite, a software for automated phenotypic screens using light microscopy and FIB-SEM. J Cell Biol 2022; 222:213779. [PMID: 36562752 PMCID: PMC9802685 DOI: 10.1083/jcb.202209127] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/28/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
In recent years, Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) has emerged as a flexible method that enables semi-automated volume ultrastructural imaging. We present a toolset for adherent cells that enables tracking and finding cells, previously identified in light microscopy (LM), in the FIB-SEM, along with the automatic acquisition of high-resolution volume datasets. We detect the underlying grid pattern in both modalities (LM and EM), to identify common reference points. A combination of computer vision techniques enables complete automation of the workflow. This includes setting the coincidence point of both ion and electron beams, automated evaluation of the image quality and constantly tracking the sample position with the microscope's field of view reducing or even eliminating operator supervision. We show the ability to target the regions of interest in EM within 5 µm accuracy while iterating between different targets and implementing unattended data acquisition. Our results demonstrate that executing volume acquisition in multiple locations autonomously is possible in EM.
Collapse
Affiliation(s)
- José M. Serra Lleti
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anna M. Steyer
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Anna M. Steyer:
| | - Nicole L. Schieber
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Beate Neumann
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christian Tischer
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Volker Hilsenstein
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | | | | | - John M. Lucocq
- Medical and Biological Sciences, Schools of Medicine and Biology, University of St. Andrews, St. Andrews, UK
| | - Rainer Pepperkok
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Yannick Schwab
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany,Correspondence to Yannick Schwab:
| |
Collapse
|
2
|
Tran HT, Lucas MS, Ishikawa T, Shahmoradian SH, Padeste C. A Compartmentalized Neuronal Cell-Culture Platform Compatible With Cryo-Fixation by High-Pressure Freezing for Ultrastructural Imaging. Front Neurosci 2021; 15:726763. [PMID: 34566569 PMCID: PMC8455873 DOI: 10.3389/fnins.2021.726763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/17/2021] [Indexed: 12/29/2022] Open
Abstract
The human brain contains a wide array of billions of neurons and interconnections, which are often simplified for analysis in vitro using compartmentalized microfluidic devices for neuronal cell culturing, to better understand neuronal development and disease. However, such devices are traditionally incompatible for high-pressure freezing and high-resolution nanoscale imaging and analysis of their sub-cellular processes by methods including electron microscopy. Here we develop a novel compartmentalized neuronal co-culture platform allowing reconstruction of neuronal networks with high variable spatial control, which is uniquely compatible for high-pressure freezing. This cryo-fixation method is well-established to enable high-fidelity preservation of the reconstructed neuronal networks and their sub-cellular processes in a near-native vitreous state without requiring chemical fixatives. To direct the outgrowth of neurites originating from two distinct groups of neurons growing in the two different compartments, polymer microstructures akin to microchannels are fabricated atop of sapphire disks. Two populations of neurons expressing either enhanced green fluorescent protein (EGFP) or mCherry were grown in either compartment, facilitating the analysis of the specific interactions between the two separate groups of cells. Neuronally differentiated PC12 cells, murine hippocampal and striatal neurons were successfully used in this context. The design of this device permits direct observation of entire neuritic processes within microchannels by optical microscopy with high spatial and temporal resolution, prior to processing for high-pressure freezing and electron microscopy. Following freeze substitution, we demonstrate that it is possible to process the neuronal networks for ultrastructural imaging by electron microscopy. Several key features of the embedded neuronal networks, including mitochondria, synaptic vesicles, axonal terminals, microtubules, with well-preserved ultrastructures were observed at high resolution using focused ion beam - scanning electron microscopy (FIB-SEM) and serial sectioning - transmission electron microscopy (TEM). These results demonstrate the compatibility of the platform with optical microscopy, high-pressure freezing and electron microscopy. The platform can be extended to neuronal models of brain disease or development in future studies, enabling the investigation of subcellular processes at the nanoscale within two distinct groups of neurons in a functional neuronal pathway, as well as pharmacological testing and drug screening.
Collapse
Affiliation(s)
- Hung Tri Tran
- Laboratory of Nanoscale Biology, Paul Scherrer Institute, Villigen, Switzerland
| | - Miriam S. Lucas
- Scientific Center for Optical and Electron Microscopy ScopeM, ETH Zürich, Zurich, Switzerland
| | - Takashi Ishikawa
- Laboratory of Nanoscale Biology, Paul Scherrer Institute, Villigen, Switzerland
| | | | - Celestino Padeste
- Laboratory of Nanoscale Biology, Paul Scherrer Institute, Villigen, Switzerland
| |
Collapse
|
3
|
An accelerated procedure for approaching and imaging of optically branded region of interest in tissue. Methods Cell Biol 2020; 162:205-221. [PMID: 33707013 DOI: 10.1016/bs.mcb.2020.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Many areas of biology have benefited from advances in light microscopy (LM). However, one limitation of the LM approach is that numerous critically important aspects of subcellular machineries are well beyond the resolution of conventional LM. For studying these, electron microscopy (EM) remains the technique of choice to visualize and identify macromolecules at the ultrastructural level. The most powerful approach is combining both techniques, LM and EM (i.e., to apply correlative light/electron microscopy, CLEM) to image exactly the same region of interest. This combination allows, for example, to immuno-localize proteins by LM and then to visualize the ultrastructural context of the same region of the sample. However, the identification and correlation of the regions of interest (ROIs) at the levels of LM and EM remains a major challenge, mostly due to the difficulties with correlation along the Z-axis for both modalities. In this chapter, we address this difficulty and describe an approach for performing CLEM in tissue samples using marks from near-infrared branding as indicators of a ROI, and then using serial block face-scanning electron microscopy (SBF-SEM) to identify and approach this ROI. Once a ROI has been approached, serial sections are collected on grids for high-resolution imaging by transmission EM, and subsequent correlation with LM images showing labeled proteins.
Collapse
|
4
|
Di Francesco V, Gurgone D, Palomba R, Ferreira MFM, Catelani T, Cervadoro A, Maffia P, Decuzzi P. Modulating Lipoprotein Transcellular Transport and Atherosclerotic Plaque Formation in ApoE -/- Mice via Nanoformulated Lipid-Methotrexate Conjugates. ACS APPLIED MATERIALS & INTERFACES 2020; 12:37943-37956. [PMID: 32805983 PMCID: PMC7453397 DOI: 10.1021/acsami.0c12202] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 07/28/2020] [Indexed: 05/02/2023]
Abstract
Macrophage inflammation and maturation into foam cells, following the engulfment of oxidized low-density lipoproteins (oxLDL), are major hallmarks in the onset and progression of atherosclerosis. Yet, chronic treatments with anti-inflammatory agents, such as methotrexate (MTX), failed to modulate disease progression, possibly for the limited drug bioavailability and plaque deposition. Here, MTX-lipid conjugates, based on 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), were integrated in the structure of spherical polymeric nanoparticles (MTX-SPNs) or intercalated in the lipid bilayer of liposomes (MTX-LIP). Although, both nanoparticles were colloidally stable with an average diameter of ∼200 nm, MTX-LIP exhibited a higher encapsulation efficiency (>70%) and slower release rate (∼50% at 10 h) compared to MTX-SPN. In primary bone marrow derived macrophages (BMDMs), MTX-LIP modulated the transcellular transport of oxLDL more efficiently than free MTX mostly by inducing a 2-fold overexpression of ABCA1 (regulating oxLDL efflux), while the effect on CD36 and SRA-1 (regulating oxLDL influx) was minimal. Furthermore, in BMDMs, MTX-LIP showed a stronger anti-inflammatory activity than free MTX, reducing the expression of IL-1β by 3-fold, IL-6 by 2-fold, and also moderately of TNF-α. In 28 days high-fat-diet-fed apoE-/- mice, MTX-LIP reduced the mean plaque area by 2-fold and the hematic amounts of RANTES by half as compared to free MTX. These results would suggest that the nanoenhanced delivery to vascular plaques of the anti-inflammatory DSPE-MTX conjugate could effectively modulate the disease progression by halting monocytes' maturation and recruitment already at the onset of atherosclerosis.
Collapse
Affiliation(s)
- Valentina Di Francesco
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
- Department
of Informatics, Bioengineering, Robotics and System Engineering, University of Genoa, Via Opera Pia, 13, 16145 Genoa, Italy
| | - Danila Gurgone
- Centre
for Immunobiology, Institute of Infection, Immunity and Inflammation,
College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
- Department
of Pharmacy, University of Naples Federico
II, Naples 80131, Italy
| | - Roberto Palomba
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | | | - Tiziano Catelani
- Electron
Microscopy Facility, Istituto Italiano di
Tecnologia, via Morego
30, Genova 16163, Italy
| | - Antonio Cervadoro
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| | - Pasquale Maffia
- Centre
for Immunobiology, Institute of Infection, Immunity and Inflammation,
College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
- Department
of Pharmacy, University of Naples Federico
II, Naples 80131, Italy
- Institute
of Cardiovascular and Medical Sciences, College of Medical, Veterinary
and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Paolo Decuzzi
- Laboratory
of Nanotechnology for Precision Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genoa, Italy
| |
Collapse
|
5
|
Kaniyala Melanthota S, Banik S, Chakraborty I, Pallen S, Gopal D, Chakrabarti S, Mazumder N. Elucidating the microscopic and computational techniques to study the structure and pathology of SARS-CoVs. Microsc Res Tech 2020; 83:1623-1638. [PMID: 32770582 PMCID: PMC7436590 DOI: 10.1002/jemt.23551] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 12/11/2022]
Abstract
Severe Acute Respiratory Syndrome Coronaviruses (SARS‐CoVs), causative of major outbreaks in the past two decades, has claimed many lives all over the world. The virus effectively spreads through saliva aerosols or nasal discharge from an infected person. Currently, no specific vaccines or treatments exist for coronavirus; however, several attempts are being made to develop possible treatments. Hence, it is important to study the viral structure and life cycle to understand its functionality, activity, and infectious nature. Further, such studies can aid in the development of vaccinations against this virus. Microscopy plays an important role in examining the structure and topology of the virus as well as pathogenesis in infected host cells. This review deals with different microscopy techniques including electron microscopy, atomic force microscopy, fluorescence microscopy as well as computational methods to elucidate various prospects of this life‐threatening virus. Structural analysis of SARS‐CoVs aids in understanding its nature, activity, and pathophysiology Revealing the surface morphology of SARS‐CoVs using scanning electron microscope and atomic force microscopy Computational methods help to understand the structure of SARS‐CoVs and their interactions with various inhibitors
Collapse
Affiliation(s)
- Sindhoora Kaniyala Melanthota
- Department of Biophysics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Soumyabrata Banik
- Department of Biophysics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Ishita Chakraborty
- Department of Biophysics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Sparsha Pallen
- Department of Bioinformatics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Dharshini Gopal
- Department of Bioinformatics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Shweta Chakrabarti
- Department of Bioinformatics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| | - Nirmal Mazumder
- Department of Biophysics, Manipal School of Life SciencesManipal Academy of Higher EducationManipalKarnataka576104India
| |
Collapse
|
6
|
Darkow E, Rog-Zielinska EA, Madl J, Brandel A, Siukstaite L, Omidvar R, Kohl P, Ravens U, Römer W, Peyronnet R. The Lectin LecA Sensitizes the Human Stretch-Activated Channel TREK-1 but Not Piezo1 and Binds Selectively to Cardiac Non-myocytes. Front Physiol 2020; 11:457. [PMID: 32499717 PMCID: PMC7243936 DOI: 10.3389/fphys.2020.00457] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/15/2020] [Indexed: 12/16/2022] Open
Abstract
The healthy heart adapts continuously to a complex set of dynamically changing mechanical conditions. The mechanical environment is altered by, and contributes to, multiple cardiac diseases. Mechanical stimuli are detected and transduced by cellular mechano-sensors, including stretch-activated ion channels (SAC). The precise role of SAC in the heart is unclear, in part because there are few SAC-specific pharmacological modulators. That said, most SAC can be activated by inducers of membrane curvature. The lectin LecA is a virulence factor of Pseudomonas aeruginosa and essential for P. aeruginosa-induced membrane curvature, resulting in formation of endocytic structures and bacterial cell invasion. We investigate whether LecA modulates SAC activity. TREK-1 and Piezo1 have been selected, as they are widely expressed in the body, including cardiac tissue, and they are “canonical representatives” for the potassium selective and the cation non-selective SAC families, respectively. Live cell confocal microscopy and electron tomographic imaging were used to follow binding dynamics of LecA, and to track changes in cell morphology and membrane topology in human embryonic kidney (HEK) cells and in giant unilamellar vesicles (GUV). HEK cells were further transfected with human TREK-1 or Piezo1 constructs, and ion channel activity was recorded using the patch-clamp technique. Finally, freshly isolated cardiac cells were used for studies into cell type dependency of LecA binding. LecA (500 nM) binds within seconds to the surface of HEK cells, with highest concentration at cell-cell contact sites. Local membrane invaginations are detected in the presence of LecA, both in the plasma membrane of cells (by 17 min of LecA exposure) as well as in GUV. In HEK cells, LecA sensitizes TREK-1, but not Piezo1, to voltage and mechanical stimulation. In freshly isolated cardiac cells, LecA binds to non-myocytes, but not to ventricular or atrial cardiomyocytes. This cell type specific lack of binding is observed across cardiomyocytes from mouse, rabbit, pig, and human. Our results suggest that LecA may serve as a pharmacological tool to study SAC in a cell type-preferential manner. This could aid tissue-based research into the roles of SAC in cardiac non-myocytes.
Collapse
Affiliation(s)
- Elisa Darkow
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Eva A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Josef Madl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Annette Brandel
- Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Lina Siukstaite
- Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Ramin Omidvar
- Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Ursula Ravens
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Winfried Römer
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
7
|
Correlative light and scanning electron microscopy (CLSEM) for analysis of bacterial infection of polarized epithelial cells. Sci Rep 2019; 9:17079. [PMID: 31745114 PMCID: PMC6863815 DOI: 10.1038/s41598-019-53085-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/16/2019] [Indexed: 12/11/2022] Open
Abstract
Infection of mammalian host cells by bacterial pathogens is a highly dynamic process and microscopy is instrumental to reveal the cellular and molecular details of host-pathogen interactions. Correlative light and electron microscopy (CLEM) combines the advantages of three-dimensional live cell imaging with ultrastructural analysis. The analyses of adhesion to, and invasion of polarized epithelial cells by pathogens often deploys scanning electron microscopy (SEM), since surface structures of the apical brush border can be analyzed in detail. Most available CLEM approaches focus on relocalization of separated single cells in different imaging modalities, but are not readily applicable to polarized epithelial cell monolayers, since orientation marks on substrate are overgrown during differentiation. To address this problem, we developed a simple and convenient workflow for correlative light and scanning electron microscopy (CLSEM), using gold mesh grids as carrier for growth of epithelial cell monolayers, and for imaging infection. The approach allows fast live cell imaging of bacterial infection of polarized cells with subsequent analyses by SEM. As examples for CLSEM applications, we investigated trigger invasion by Salmonella enterica, zipper invasion by Listeria monocytogenes, and the enterocyte attachment and effacement phenotype of enteropathogenic Escherichia coli. Our study demonstrates the versatile use of gold mesh grids for CLSEM of the interaction of bacterial pathogens with the apical side of polarized epithelial cells.
Collapse
|
8
|
Sachse M, Fernández de Castro I, Tenorio R, Risco C. The viral replication organelles within cells studied by electron microscopy. Adv Virus Res 2019; 105:1-33. [PMID: 31522702 PMCID: PMC7112055 DOI: 10.1016/bs.aivir.2019.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Transmission electron microscopy (TEM) has been crucial to study viral infections. As a result of recent advances in light and electron microscopy, we are starting to be aware of the variety of structures that viruses assemble inside cells. Viruses often remodel cellular compartments to build their replication factories. Remarkably, viruses are also able to induce new membranes and new organelles. Here we revise the most relevant imaging technologies to study the biogenesis of viral replication organelles. Live cell microscopy, correlative light and electron microscopy, cryo-TEM, and three-dimensional imaging methods are unveiling how viruses manipulate cell organization. In particular, methods for molecular mapping in situ in two and three dimensions are revealing how macromolecular complexes build functional replication complexes inside infected cells. The combination of all these imaging approaches is uncovering the viral life cycle events with a detail never seen before.
Collapse
Affiliation(s)
- Martin Sachse
- Unité Technologie et service BioImagerie Ultrastructurale, Institut Pasteur, Paris, France.
| | | | - Raquel Tenorio
- Cell Structure Laboratory, National Center for Biotechnology, CSIC, Madrid, Spain
| | - Cristina Risco
- Cell Structure Laboratory, National Center for Biotechnology, CSIC, Madrid, Spain.
| |
Collapse
|
9
|
Reichelt M, Sagolla M, Katakam AK, Webster JD. Unobstructed Multiscale Imaging of Tissue Sections for Ultrastructural Pathology Analysis by Backscattered Electron Scanning Microscopy. J Histochem Cytochem 2019; 68:9-23. [PMID: 31385742 DOI: 10.1369/0022155419868992] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ultrastructural analysis of healthy, diseased, or experimental tissues is essential in diagnostic and investigative pathology. Evaluation of large tissue areas with suborganelle resolution is challenging because biological structures ranging from several millimeters to nanometers in size need to be identified and imaged while maintaining context over multiple scales. Imaging with field emission scanning electron microscopes (FE-SEMs) is uniquely suited for this task. We describe an efficient workflow for the preparation and unobstructed multiscale imaging of tissue sections with backscattered electron scanning electron microscopy (BSE-SEM) for applications in ultrastructural pathology. We demonstrate that a diverse range of tissues, processed by conventional electron microscopy protocols and avoiding the use of mordanting agents, can be imaged on standard glass slides over multiple scales, from the histological to the ultrastructural level, without any visual obstructions. Our workflow takes advantage of the very large scan fields possible with modern FE-SEMs that allow for the acquisition of wide-field overview images which can be explored at the ultrastructural level by digitally zooming into the images. Examples from applications in pulmonary research and neuropathology demonstrate the versatility and efficiency of this method. This BSE-SEM-based multiscale imaging procedure promises to substantially simplify and accelerate ultrastructural tissue analysis in pathology.
Collapse
Affiliation(s)
- Mike Reichelt
- Department of Pathology, Genentech Inc., South San Francisco, California
| | - Meredith Sagolla
- Department of Pathology, Genentech Inc., South San Francisco, California
| | - Anand K Katakam
- Department of Pathology, Genentech Inc., South San Francisco, California
| | - Joshua D Webster
- Department of Pathology, Genentech Inc., South San Francisco, California
| |
Collapse
|