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Mou X, Shah J, Roye Y, Du C, Musah S. An ultrathin membrane mediates tissue-specific morphogenesis and barrier function in a human kidney chip. SCIENCE ADVANCES 2024; 10:eadn2689. [PMID: 38838141 PMCID: PMC11152122 DOI: 10.1126/sciadv.adn2689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/30/2024] [Indexed: 06/07/2024]
Abstract
Organ-on-chip (OOC) systems are revolutionizing tissue engineering by providing dynamic models of tissue structure, organ-level function, and disease phenotypes using human cells. However, nonbiological components of OOC devices often limit the recapitulation of in vivo-like tissue-tissue cross-talk and morphogenesis. Here, we engineered a kidney glomerulus-on-a-chip that recapitulates glomerular morphogenesis and barrier function using a biomimetic ultrathin membrane and human-induced pluripotent stem cells. The resulting chip comprised a proximate epithelial-endothelial tissue interface, which reconstituted the selective molecular filtration function of healthy and diseased kidneys. In addition, fenestrated endothelium was successfully induced from human pluripotent stem cells in an OOC device, through in vivo-like paracrine signaling across the ultrathin membrane. Thus, this device provides a dynamic tissue engineering platform for modeling human kidney-specific morphogenesis and function, enabling mechanistic studies of stem cell differentiation, organ physiology, and pathophysiology.
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Affiliation(s)
- Xingrui Mou
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27710, USA
| | - Jessica Shah
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27710, USA
| | - Yasmin Roye
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27710, USA
| | - Carolyn Du
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27710, USA
| | - Samira Musah
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27710, USA
- Center for Biomolecular and Tissue Engineering, Duke University, Durham, NC 27710, USA
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
- Affiliate Faculty of the Developmental and Stem Cell Biology Program, Duke Regeneration Center, Duke MEDx Initiative, Duke University, Durham, NC 27710, USA
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2
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Qu R, Du W, Li S, Li W, Wei G, Chen Z, Gao H, Shi S, Zou L, Li H. Destruction of vascular endothelial glycocalyx during formation of pre-metastatic niches. Heliyon 2024; 10:e29101. [PMID: 38601565 PMCID: PMC11004892 DOI: 10.1016/j.heliyon.2024.e29101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 03/29/2024] [Accepted: 03/31/2024] [Indexed: 04/12/2024] Open
Abstract
A special microenvironment called the "pre-metastatic niche" is thought to help primary tumor cells migrate to new tissues and invade them, in part because the normal barrier function of the vascular endothelium is compromised. While the primary tumor itself can promote the creation of such niches by secreting pro-metastatic factors, the underlying molecular mechanisms are still poorly understood. Here, we show that the injection of primary tumor-secreted pro-metastatic factors from B16F10 melanoma or 4T1 breast cancer cells into healthy mice can induce the destruction of the vascular endothelial glycocalyx, which is a polysaccharide coating on the vascular endothelial lumen that normally inhibits tumor cell passage into and out of the circulation. However, when human umbilical vein endothelial cultures were treated in vitro with these secreted pro-metastatic factors, no significant destruction of the glycocalyx was observed, implying that this destruction requires a complex in vivo microenvironment. The tissue section analysis revealed that secreted pro-metastatic factors could clearly upregulate macrophage-related molecules such as CD11b and tumor necrosis factor-α (TNF-α) in the heart, liver, spleen, lung, and kidney, which is associated with the upregulation and activation of heparanase. In addition, macrophage depletion significantly attenuated the degradation of the vascular endothelial glycocalyx induced by secreted pro-metastatic factors. This indicates that the secreted pro-metastatic factors that destroy the vascular endothelial glycocalyx rely primarily on macrophages. Our findings suggest that the formation of pre-metastatic niches involves degradation of the vascular endothelial glycocalyx, which may hence be a useful target for developing therapies to inhibit cancer metastasis.
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Affiliation(s)
- Rui Qu
- Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu, 610106, China
| | - Wenxuan Du
- Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu, 610106, China
| | - Shuyao Li
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Wei Li
- School of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Guangfei Wei
- Clinical Medical Research Center, Zhenjiang Hospital of Integrated Traditional Chinese and Western Medicine, Zhenjiang, 212004, China
| | - Zhoujiang Chen
- School of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Huile Gao
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research, Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Sanjun Shi
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Liang Zou
- School of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Hanmei Li
- School of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
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Saitoh S, Takaki T, Nakajima K, Wo B, Terashima H, Shimo S, Nguyen HB, Thai TQ, Kumamoto K, Kunisawa K, Nagao S, Tojo A, Ohno N, Takahashi K. Treatment of tubular damage in high-fat-diet-fed obese mice using sodium-glucose co-transporter inhibitors. PLoS One 2023; 18:e0281770. [PMID: 36780539 PMCID: PMC9925073 DOI: 10.1371/journal.pone.0281770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 01/31/2023] [Indexed: 02/15/2023] Open
Abstract
A long-term high-fat diet (HFD) causes obesity and changes in renal lipid metabolism and lysosomal dysfunction in mice, causing renal damage. Sodium-glucose co-transporter inhibitors, including phlorizin, exert nephroprotective effects in patients with chronic kidney disease, but the underlying mechanism remains unclear. A HFD or standard diet was fed to adult C57BL/6J male mice, and phlorizin was administered. Lamellar body components of the proximal tubular epithelial cells (PTECs) were investigated. After phlorizin administration in HFD-fed mice, sphingomyelin and ceramide in urine and tissues were assessed and label-free quantitative proteomics was performed using kidney tissue samples. Mitochondrial elongation by fusion was effective in the PTECs of HFD-fed obese mice under phlorizin administration, and many lamellar bodies were found in the apical portion of the S2 segment of the proximal tubule. Phlorizin functioned as a diuretic, releasing lamellar bodies from the apical membrane of PTECs and clearing the obstruction in nephrons. The main component of the lamellar bodies was sphingomyelin. On the first day of phlorizin administration in HFD-fed obese mice, the diuretic effect was increased, and more sphingomyelin was excreted through urine than in vehicle-treated mice. The expressions of three peroxisomal β-oxidation proteins involved in fatty acid metabolism were downregulated after phlorizin administration in the kidneys of HFD-fed mice. Fatty acid elongation protein levels increased with phlorizin administration, indicating an increase in long-chain fatty acids. Lamellar bodies accumulated in the proximal renal tubule of the S2 segment of the HFD-fed mice, indicating that the urinary excretion of lamellar bodies has nephroprotective effects.
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Affiliation(s)
- Sei Saitoh
- Department of Biomedical Molecular Sciences (Anatomy II), Fujita Health University School of Medicine, Toyoake, Japan
- * E-mail:
| | - Takashi Takaki
- Department of Anatomy, Showa University School of Medicine, Tokyo, Japan
- Center for Electron microscopy, Showa University School of Medicine, Tokyo, Japan
| | - Kazuki Nakajima
- Center for Joint Research Facilities Support, Research Promotion and Support Headquarters, Fujita Health University, Toyoake, Japan
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Bao Wo
- Department of Anatomy and Molecular Histology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
- Department of Histology and Embryology, Medical College of Chifeng University, Chifeng, China
| | | | - Satoshi Shimo
- Department of Occupational Therapy, Health Science University, Fujikawaguchiko, Japan
| | - Huy Bang Nguyen
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Chuo, Japan
- Department of Anatomy, Faculty of Medicine, University of Medicine and Pharmacy (UMP), Ho Chi Minh, Vietnam
| | - Truc Quynh Thai
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Chuo, Japan
- Department of Histology Embryology Genetics, Faculty of Basic Medical Sciences, Pham Ngoc Thach University of Medicine, Ho Chi Minh, Vietnam
| | - Kanako Kumamoto
- Education and Research Facility of Animal Models for Human Diseases, Fujita Health University, Toyoake, Japan
| | - Kazuo Kunisawa
- Department of Regulatory Science for Evaluation & Development of Pharmaceuticals & Devices, Fujita Health University Graduate School of Health Sciences, Toyoake, Japan
| | - Shizuko Nagao
- Education and Research Facility of Animal Models for Human Diseases, Fujita Health University, Toyoake, Japan
| | - Akihiro Tojo
- Division of Nephrology & Hypertension, Dokkyo Medical University, Mibu, Japan
| | - Nobuhiko Ohno
- Division of Ultrastructural Research, National Institute of Physiological Sciences, Okazaki, Japan
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, Shimotsuke, Japan
| | - Kazuo Takahashi
- Department of Biomedical Molecular Sciences (Anatomy II), Fujita Health University School of Medicine, Toyoake, Japan
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Ermert K, Buhl EM, Klinkhammer BM, Floege J, Boor P. Reduction of Endothelial Glycocalyx on Peritubular Capillaries in Chronic Kidney Disease. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:138-147. [PMID: 36414084 DOI: 10.1016/j.ajpath.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 10/07/2022] [Accepted: 11/03/2022] [Indexed: 11/20/2022]
Abstract
In chronic kidney disease (CKD), peritubular capillaries undergo anatomic and functional alterations, such as rarefaction and increased permeability. The endothelial glycocalyx (EG) is a carbohydrate-rich gel-like mesh, which covers the luminal surface of endothelial cells. It is involved in many regulatory functions of the endothelium, including vascular permeability. Herein, we investigated ultrastructural alterations of the EG in different murine CKD models. Fluorescence staining using different lectins with high affinity to components of the renal glycocalyx revealed a reduced binding to the endothelium in CKD in the animal models, and there were similar finding in human kidney specimens. Lanthanum Dysprosium Glycosamino Glycan adhesion staining technique was used to visualize the ultrastructure of the glycocalyx in transmission electron microscopy. This also enabled quantitative analyses, showing a significant reduction of the EG thickness and density. In addition, mRNA expression of proteins involved in glycocalyx biology, synthesis, and turnover (ie, syndecan 1 and glypican 1), which are main components of the glycocalyx, and exostosin 2, involved in the synthesis of the glycocalyx, were significantly up-regulated in endothelial cells isolated from murine CKD models. Visualization of glycocalyx using specific transmission electron microscopy analyses allows qualitative and quantitative analyses and revealed significant pathologic alterations in peritubular capillaries in CKD.
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Affiliation(s)
- Katja Ermert
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany; Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Eva M Buhl
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany; Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany; Electron Microscopy Facility, RWTH Aachen University Hospital, Aachen, Germany
| | - Barbara M Klinkhammer
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany; Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Jürgen Floege
- Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany
| | - Peter Boor
- Institute of Pathology, RWTH Aachen University Hospital, Aachen, Germany; Division of Nephrology and Immunology, RWTH Aachen University Hospital, Aachen, Germany; Electron Microscopy Facility, RWTH Aachen University Hospital, Aachen, Germany.
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Pisarenka S, Meyer NC, Xiao X, Goodfellow R, Nester CM, Zhang Y, Smith RJH. Modeling C3 glomerulopathies: C3 convertase regulation on an extracellular matrix surface. Front Immunol 2023; 13:1073802. [PMID: 36846022 PMCID: PMC9947773 DOI: 10.3389/fimmu.2022.1073802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023] Open
Abstract
Introduction C3 glomerulopathies (C3G) are ultra-rare complement-mediated diseases that lead to end-stage renal disease (ESRD) within 10 years of diagnosis in ~50% of patients. Overactivation of the alternative pathway (AP) of complement in the fluid phase and on the surface of the glomerular endothelial glycomatrix is the underlying cause of C3G. Although there are animal models for C3G that focus on genetic drivers of disease, in vivo studies of the impact of acquired drivers are not yet possible. Methods Here we present an in vitro model of AP activation and regulation on a glycomatrix surface. We use an extracellular matrix substitute (MaxGel) as a base upon which we reconstitute AP C3 convertase. We validated this method using properdin and Factor H (FH) and then assessed the effects of genetic and acquired drivers of C3G on C3 convertase. Results We show that C3 convertase readily forms on MaxGel and that this formation was positively regulated by properdin and negatively regulated by FH. Additionally, Factor B (FB) and FH mutants impaired complement regulation when compared to wild type counterparts. We also show the effects of C3 nephritic factors (C3Nefs) on convertase stability over time and provide evidence for a novel mechanism of C3Nef-mediated C3G pathogenesis. Discussion We conclude that this ECM-based model of C3G offers a replicable method by which to evaluate the variable activity of the complement system in C3G, thereby offering an improved understanding of the different factors driving this disease process.
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Affiliation(s)
- Sofiya Pisarenka
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
- Molecular Medicine Graduate Program, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Nicole C. Meyer
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Xue Xiao
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Renee Goodfellow
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Carla M. Nester
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Yuzhou Zhang
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Richard J. H. Smith
- Molecular Otolaryngology and Renal Research Laboratories, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
- Molecular Medicine Graduate Program, Caver College of Medicine, University of Iowa, Iowa City, IA, United States
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6
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Siegerist F, Drenic V, Koppe TM, Telli N, Endlich N. Super-Resolution Microscopy: A Technique to Revolutionize Research and Diagnosis of Glomerulopathies. GLOMERULAR DISEASES 2022; 3:19-28. [PMID: 36816428 PMCID: PMC9936760 DOI: 10.1159/000528713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Background For decades, knowledge about glomerular (patho)physiology has been tightly linked with advances in microscopic imaging technology. For example, the invention of electron microscopy was required to hypothesize about the mode of glomerular filtration barrier function. Summary Super-resolution techniques, defined as fluorescence microscopy approaches that surpass the optical resolution limit of around 200 nm, have been made available to the scientific community. Several of these different techniques are currently in use in glomerular research. Using three-dimensional structured illumination microscopy, the exact morphology of the podocyte filtration slit can be morphometrically analyzed and quantitatively compared across samples originating from animal models or human biopsies. Key Messages Several quantitative image analysis approaches and their potential influence on glomerular research and diagnostics are discussed. By improving not only optical resolution but also information content and turnaround time, super-resolution microscopy has the potential to expand the diagnosis of glomerular disease. Soon, these approaches could be introduced into glomerular disease diagnosis.
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Affiliation(s)
- Florian Siegerist
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | | | - Thor-Magnus Koppe
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | | | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany,NIPOKA GmbH, Greifswald, Germany,*Nicole Endlich,
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Santos R, Bürgi M, Mateos JM, Luciani A, Loffing J. Too bright for 2 dimensions: recent progress in advanced 3-dimensional microscopy of the kidney. Kidney Int 2022; 102:1238-1246. [PMID: 35963448 DOI: 10.1016/j.kint.2022.06.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/19/2022] [Accepted: 06/24/2022] [Indexed: 01/12/2023]
Abstract
The kidney is a structurally and functionally complex organ responsible for the control of water, ion, and other solute homeostasis. Moreover, the kidneys excrete metabolic waste products and produce hormones, such as renin and erythropoietin. The functional unit of the kidney is the nephron, which is composed by a serial arrangement of a filter unit called the renal corpuscle and several tubular segments that modulate the filtered fluid by reabsorption and secretion. Within each kidney, thousands of nephrons are closely intermingled and surrounded by an intricate network of blood vessels and various interstitial cell types, including fibroblasts and immune cells. This complex tissue architecture is essential for proper kidney function. In fact, kidney disease is often reflected or even caused by a derangement of the histologic structures. Frequently, kidney histology is studied using microscopic analysis of 2-dimensional tissue sections, which, however, misses important 3-dimensional spatial information. Reconstruction of serial sections tries to overcome this limitation, but is technically challenging, time-consuming, and often inherently linked to sectioning artifacts. In recent years, advances in tissue preparation (e.g., optical clearing) and new light- and electron-microscopic methods have provided novel avenues for 3-dimensional kidney imaging. Combined with novel machine-learning algorithms, these approaches offer unprecedented options for large-scale and automated analysis of kidney structure and function. This review provides a brief overview of these emerging imaging technologies and presents key examples of how these approaches are already used to study the normal and the diseased kidney.
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Affiliation(s)
- Rui Santos
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Max Bürgi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - José María Mateos
- Centre for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Alessandro Luciani
- Institute of Physiology, University of Zurich, Zurich, Switzerland; National Centre of Competence in Research "Kidney.CH," University of Zurich, Zurich, Switzerland
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; National Centre of Competence in Research "Kidney.CH," University of Zurich, Zurich, Switzerland.
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Kunishima N, Hirose R, Takeda Y, Ito K, Furuichi K, Omote K. Nondestructive cellular-level 3D observation of mouse kidney using laboratory-based X-ray microscopy with paraffin-mediated contrast enhancement. Sci Rep 2022; 12:9436. [PMID: 35676517 PMCID: PMC9177607 DOI: 10.1038/s41598-022-13394-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 05/13/2022] [Indexed: 11/26/2022] Open
Abstract
For three-dimensional observation of unstained bio-specimens using X-ray microscopy with computed tomography (CT), one main problem has been low contrast in X-ray absorption. Here we introduce paraffin-mediated contrast enhancement to visualize biopsy samples of mouse kidney using a laboratory-based X-tray microscope. Unlike conventional heavy-atom staining, paraffin-mediated contrast enhancement uses solid paraffin as a negative contrast medium to replace water in the sample. The medium replacement from water to paraffin effectively lowers the absorption of low-energy X-rays by the medium, which eventually enhances the absorption contrast between the medium and tissue. In this work, paraffin-mediated contrast enhancement with 8 keV laboratory X-rays was used to visualize cylindrical renal biopsies with diameters of about 0.5 mm. As a result, reconstructed CT images from 19.4 h of data collection achieved cellular-level resolutions in all directions, which provided 3D structures of renal corpuscles from a normal mouse and from a disease model mouse. These two structures with and without disease allowed a volumetric analysis showing substantial volume differences in glomerular subregions. Notably, this nondestructive method presents CT opacities reflecting elemental composition and density of unstained tissues, thereby allowing more unbiased interpretation on their biological structures.
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9
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Nizamundeen ZA, ElSaboni L, Vetch G, Karim J, Neal CR, Allen CL, Bates DO, Arkill KP. Transmission Electron Microscopy of Endothelium. Methods Mol Biol 2022; 2441:95-103. [PMID: 35099731 DOI: 10.1007/978-1-0716-2059-5_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Transmission electron microscopy using resin sections still remains an exceptionally useful tool in evaluating cellular ultrastucture within tissue. For the endothelium the best method for maintaining such structure is perfusion fixation: fixing the tissue under physiological pressure. Here the focus is on a method of maintaining the vascular wall structure including the endothelial glycocalyx and extending this with tilt series tomography. Shown are typical histological sections from multiple capillary beds including brain, heart and retina using a lanthanide staining technique (LaDy GAGa) to highlight that the differences in normo-physiology are substantial.It is hoped that users will find the notes useful in deciding which specific staining and imaging method would suit their needs so this technically challenging, and low throughput methodology, is used to its best effect.
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Affiliation(s)
- Zubair Ahmed Nizamundeen
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Loubna ElSaboni
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Grace Vetch
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Jumana Karim
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Chris R Neal
- Wolfson BioImaging, Biomedical Sciences, University of Bristol, Bristol, UK
| | | | - David O Bates
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK
| | - Kenton P Arkill
- Tumour and Vascular Biology Laboratories, Centre for Cancer Sciences, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, UK.
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10
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Qu C, Roth R, Puapatanakul P, Loitman C, Hammad D, Genin GM, Miner JH, Suleiman HY. Three-Dimensional Visualization of the Podocyte Actin Network Using Integrated Membrane Extraction, Electron Microscopy, and Machine Learning. J Am Soc Nephrol 2022; 33:155-173. [PMID: 34758982 PMCID: PMC8763187 DOI: 10.1681/asn.2021020182] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 10/19/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Actin stress fibers are abundant in cultured cells, but little is known about them in vivo. In podocytes, much evidence suggests that mechanobiologic mechanisms underlie podocyte shape and adhesion in health and in injury, with structural changes to actin stress fibers potentially responsible for pathologic changes to cell morphology. However, this hypothesis is difficult to rigorously test in vivo due to challenges with visualization. A technology to image the actin cytoskeleton at high resolution is needed to better understand the role of structures such as actin stress fibers in podocytes. METHODS We developed the first visualization technique capable of resolving the three-dimensional cytoskeletal network in mouse podocytes in detail, while definitively identifying the proteins that comprise this network. This technique integrates membrane extraction, focused ion-beam scanning electron microscopy, and machine learning image segmentation. RESULTS Using isolated mouse glomeruli from healthy animals, we observed actin cables and intermediate filaments linking the interdigitated podocyte foot processes to newly described contractile actin structures, located at the periphery of the podocyte cell body. Actin cables within foot processes formed a continuous, mesh-like, electron-dense sheet that incorporated the slit diaphragms. CONCLUSIONS Our new technique revealed, for the first time, the detailed three-dimensional organization of actin networks in healthy podocytes. In addition to being consistent with the gel compression hypothesis, which posits that foot processes connected by slit diaphragms act together to counterbalance the hydrodynamic forces across the glomerular filtration barrier, our data provide insight into how podocytes respond to mechanical cues from their surrounding environment.
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Affiliation(s)
- Chengqing Qu
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Charles Loitman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Dina Hammad
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Guy M. Genin
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Jeffrey H. Miner
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri,Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Hani Y. Suleiman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
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11
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Müller-Deile J, Sopel N, Ohs A, Rose V, Gröner M, Wrede C, Hegermann J, Daniel C, Amann K, Zahner G, Schiffer M. Glomerular Endothelial Cell-Derived microRNA-192 Regulates Nephronectin Expression in Idiopathic Membranous Glomerulonephritis. J Am Soc Nephrol 2021; 32:2777-2794. [PMID: 34716242 PMCID: PMC8806098 DOI: 10.1681/asn.2020121699] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 07/09/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Autoantibodies binding to podocyte antigens cause idiopathic membranous glomerulonephritis (iMGN). However, it remains elusive how autoantibodies reach the subepithelial space because the glomerular filtration barrier (GFB) is size selective and almost impermeable for antibodies. METHODS Kidney biopsies from patients with iMGN, cell culture, zebrafish, and mouse models were used to investigate the role of nephronectin (NPNT) regulating microRNAs (miRs) for the GFB. RESULTS Glomerular endothelial cell (GEC)-derived miR-192-5p and podocyte-derived miR-378a-3p are upregulated in urine and glomeruli of patients with iMGN, whereas glomerular NPNT is reduced. Overexpression of miR-192-5p and morpholino-mediated npnt knockdown induced edema, proteinuria, and podocyte effacement similar to podocyte-derived miR-378a-3p in zebrafish. Structural changes of the glomerular basement membrane (GBM) with increased lucidity, splitting, and lamellation, especially of the lamina rara interna, similar to ultrastructural findings seen in advanced stages of iMGN, were found. IgG-size nanoparticles accumulated in lucidity areas of the lamina rara interna and lamina densa of the GBM in npnt-knockdown zebrafish models. Loss of slit diaphragm proteins and severe structural impairment of the GBM were further confirmed in podocyte-specific Npnt knockout mice. GECs downregulate podocyte NPNT by transfer of miR-192-5p-containing exosomes in a paracrine manner. CONCLUSIONS Podocyte NPNT is important for proper glomerular filter function and GBM structure and is regulated by GEC-derived miR-192-5p and podocyte-derived miR-378a-3p. We hypothesize that loss of NPNT in the GBM is an important part of the initial pathophysiology of iMGN and enables autoantigenicity of podocyte antigens and subepithelial immune complex deposition in iMGN.
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Affiliation(s)
- Janina Müller-Deile
- Department of Nephrology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nina Sopel
- Department of Nephrology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Alexandra Ohs
- Department of Nephrology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Victoria Rose
- Department of Nephrology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Marwin Gröner
- Research Center On Rare Kidney Diseases (RECORD), University Hospital Erlangen, Erlangen, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Medizinische Hochschule Hannover, Hannover, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Gunther Zahner
- Department of Medicine, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Mario Schiffer
- Department of Nephrology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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12
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Grubb A. Glomerular filtration and shrunken pore syndrome in children and adults. Acta Paediatr 2021; 110:2503-2508. [PMID: 33742469 DOI: 10.1111/apa.15846] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 01/10/2023]
Abstract
A major function of the kidney is to, by glomerular filtration, maintain the overall steady-state of 5-30 kDa proteins, many of which are signalling molecules. This function of the kidney has been overlooked, since predominantly low-molecular-mass substances <1 kDa have been used to measure or estimate glomerular filtration rate (GFR). The use of cystatin C (13 kDa) as a marker of GFR has allowed the discovery that the filtration of 5-30 kDa molecules can be selectively impaired defining the shrunken pore syndrome. The discovery, pathophysiology, morbidity (mainly cardiovascular manifestations) and mortality of this syndrome are described.
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Affiliation(s)
- Anders Grubb
- Department of Clinical Chemistry University Hospital Lund Sweden
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13
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Arkill KP. A Reinterpretation of Evidence for the Endothelial Glycocalyx Filtration Structure. Front Cell Dev Biol 2021; 9:734661. [PMID: 34540847 PMCID: PMC8442954 DOI: 10.3389/fcell.2021.734661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/13/2021] [Indexed: 11/17/2022] Open
Abstract
The endothelial glycocalyx (eGlx) is thought to be the primary macromolecular filter for fluid flux out of the vasculature. This filter maintains the higher protein concentration within the vessel lumen relative to the tissue. Whilst the arguments for the eGlx being the size filter are convincing the structural evidence has been limited to specialized stains of perfusion fixed tissue, which are further processed for resin embedding for transmission electron microscopy. The staining and processing of the delicate pore structure has left many researchers struggling to interpret the observed surface coat. Previous work has alluded to a 19.5 nm spacing between fibers; however, whilst repeatable it does not give an eGlx pore size consistent with known glycosaminoglycan (GAG) molecular structure due to the required fiber thickness of >10 nm. Here a new interpretation is proposed based on the likelihood that the electron micrographs of are often of collapsed eGlx. The 19.5 nm spacing measured may therefore be the core protein of the proteoglycans (PGs) with the GAGs wrapped up around them rather than in an expanded in vivo state. The concept is explored to determine that this is indeed consistent with experimental measurements of permeability if the syndecans are predominately dimerized. Further an alteration of core protein lattice from hexagonal packing to square packing dramatically changes the permeability which could be facilitated via known mechanisms such as transient actin binding.
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Affiliation(s)
- Kenton P. Arkill
- School of Medicine, University of Nottingham Biodiscovery Institute, University Park, Nottingham, United Kingdom
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14
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Huo Y, Deng R, Liu Q, Fogo AB, Yang H. AI applications in renal pathology. Kidney Int 2021; 99:1309-1320. [PMID: 33581198 PMCID: PMC8154730 DOI: 10.1016/j.kint.2021.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/09/2021] [Accepted: 01/13/2021] [Indexed: 12/20/2022]
Abstract
The explosive growth of artificial intelligence (AI) technologies, especially deep learning methods, has been translated at revolutionary speed to efforts in AI-assisted healthcare. New applications of AI to renal pathology have recently become available, driven by the successful AI deployments in digital pathology. However, synergetic developments of renal pathology and AI require close interdisciplinary collaborations between computer scientists and renal pathologists. Computer scientists should understand that not every AI innovation is translatable to renal pathology, while renal pathologists should capture high-level principles of the relevant AI technologies. Herein, we provide an integrated review on current and possible future applications in AI-assisted renal pathology, by including perspectives from computer scientists and renal pathologists. First, the standard stages, from data collection to analysis, in full-stack AI-assisted renal pathology studies are reviewed. Second, representative renal pathology-optimized AI techniques are introduced. Last, we review current clinical AI applications, as well as promising future applications with the recent advances in AI.
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Affiliation(s)
- Yuankai Huo
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Ruining Deng
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Quan Liu
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee, USA
| | - Agnes B Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Haichun Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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15
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Sánchez Pina MA, Gómez-Aix C, Méndez-López E, Gosalvez Bernal B, Aranda MA. Imaging Techniques to Study Plant Virus Replication and Vertical Transmission. Viruses 2021; 13:358. [PMID: 33668729 PMCID: PMC7996213 DOI: 10.3390/v13030358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/19/2022] Open
Abstract
Plant viruses are obligate parasites that need to usurp plant cell metabolism in order to infect their hosts. Imaging techniques have been used for quite a long time to study plant virus-host interactions, making it possible to have major advances in the knowledge of plant virus infection cycles. The imaging techniques used to study plant-virus interactions have included light microscopy, confocal laser scanning microscopy, and scanning and transmission electron microscopies. Here, we review the use of these techniques in plant virology, illustrating recent advances in the area with examples from plant virus replication and virus plant-to-plant vertical transmission processes.
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Affiliation(s)
- María Amelia Sánchez Pina
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Departamento de Biología del Estrés y Patología Vegetal, Grupo de Patología Vegetal, 30100 Murcia, Spain; (E.M.-L.); (B.G.B.)
| | - Cristina Gómez-Aix
- Abiopep S.L., R&D Department, Parque Científico de Murcia, Ctra. de Madrid, Km 388, Complejo de Espinardo, Edf. R, 2º, 30100 Murcia, Spain;
| | - Eduardo Méndez-López
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Departamento de Biología del Estrés y Patología Vegetal, Grupo de Patología Vegetal, 30100 Murcia, Spain; (E.M.-L.); (B.G.B.)
| | - Blanca Gosalvez Bernal
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Departamento de Biología del Estrés y Patología Vegetal, Grupo de Patología Vegetal, 30100 Murcia, Spain; (E.M.-L.); (B.G.B.)
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Departamento de Biología del Estrés y Patología Vegetal, Grupo de Patología Vegetal, 30100 Murcia, Spain; (E.M.-L.); (B.G.B.)
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16
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Gyarmati G, Shroff UN, Riquier-Brison A, Kriz W, Kaissling B, Neal CR, Arkill KP, Ahmadi N, Gill IS, Moon JY, Desposito D, Peti-Peterdi J. A new view of macula densa cell microanatomy. Am J Physiol Renal Physiol 2021; 320:F492-F504. [PMID: 33491562 DOI: 10.1152/ajprenal.00546.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although macula densa (MD) cells are chief regulatory cells in the nephron with unique microanatomical features, they have been difficult to study in full detail due to their inaccessibility and limitations in earlier microscopy techniques. The present study used a new mouse model with a comprehensive imaging approach to visualize so far unexplored microanatomical features of MD cells, their regulation, and functional relevance. MD-GFP mice with conditional and partial induction of green fluorescent protein (GFP) expression, which specifically and intensely illuminated only single MD cells, were used with fluorescence microscopy of fixed tissue and live MD cells in vitro and in vivo with complementary electron microscopy of the rat, rabbit, and human kidney. An elaborate network of major and minor cell processes, here named maculapodia, were found at the cell base, projecting toward other MD cells and the glomerular vascular pole. The extent of maculapodia showed upregulation by low dietary salt intake and the female sex. Time-lapse imaging of maculapodia revealed highly dynamic features including rapid outgrowth and an extensive vesicular transport system. Electron microscopy of rat, rabbit, and human kidneys and three-dimensional volume reconstruction in optically cleared whole-mount MD-GFP mouse kidneys further confirmed the presence and projections of maculapodia into the extraglomerular mesangium and afferent and efferent arterioles. The newly identified dynamic and secretory features of MD cells suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD cells and between MD and other target cells.NEW & NOTEWORTHY This study illuminated a physiologically regulated dense network of basal cell major and minor processes (maculapodia) in macula densa (MD) cells. The newly identified dynamic and secretory features of these microanatomical structures suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD and other target cells. Detailed characterization of the function and molecular details of MD cell intercellular communications and their role in physiology and disease warrant further studies.
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Affiliation(s)
- Georgina Gyarmati
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Urvi Nikhil Shroff
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Anne Riquier-Brison
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Wilhelm Kriz
- Centre for Biomedicine and Medical Technology Mannheim, Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Christopher R Neal
- Bristol Renal, Bristol Heart Institute, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Kenton P Arkill
- Division of Cancer and Stem Cells, School of Medicine, University of Nottingham Biodiscovery Institute, University Park, United Kingdom
| | - Nariman Ahmadi
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Inderbir S Gill
- Institute of Urology, Catherine & Joseph Aresty Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ju-Young Moon
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Dorinne Desposito
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - János Peti-Peterdi
- Departments of Physiology and Neuroscience, and Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
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17
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Golla N, Hong LJ, Chefetz I. Visualization of Necroptotic Cell Death through Transmission Electron Microscopy. Methods Mol Biol 2021; 2255:135-147. [PMID: 34033100 DOI: 10.1007/978-1-0716-1162-3_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transmission electron microscopy (TEM) is an all-in-one tool to visualize the complex systems of any specimen that is 1 nm in size or smaller. The current chapter provides detailed guidelines for imaging morphological changes during programmed cell necrosis using TEM as a single-step methodology. In this protocol, a novel aldehyde dehydrogenase inhibitor is used to induce cell programmed necrosis in ovarian cancer cell lines (A2780 and SKOV3). This process is followed by gradient dehydration with ethanol, chemical fixation, sampled grid preparation, and staining with 0.75% uranyl formate. Following fixation and grid preparation, cells are imaged using TEM. The resulting images reveal morphological changes consistent with necrotic morphology, including swelling of cells and organelles, appearance of vacuoles, and plasma membrane rupture followed by leakage of cellular contents. The current approach allows a single-step methodology for characterization of cell-programmed necrosis in cells based on morphology.
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Affiliation(s)
- Naresh Golla
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Linda J Hong
- Division of Gynecologic Oncology, Department of Gynecology and Obstetrics, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Ilana Chefetz
- The Hormel Institute, University of Minnesota, Austin, MN, USA.
- Masonic Cancer Center, Minneapolis, MN, USA.
- Stem Cell Institute, Minneapolis, MN, USA.
- Department of Obstetrics, Gynecology and Women's Health, Minneapolis, MN, USA.
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18
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Abstract
The glomerular basement membrane (GBM) is a key component of the glomerular capillary wall and is essential for kidney filtration. The major components of the GBM include laminins, type IV collagen, nidogens and heparan sulfate proteoglycans. In addition, the GBM harbours a number of other structural and regulatory components and provides a reservoir for growth factors. New technologies have improved our ability to study the composition and assembly of basement membranes. We now know that the GBM is a complex macromolecular structure that undergoes key transitions during glomerular development. Defects in GBM components are associated with a range of hereditary human diseases such as Alport syndrome, which is caused by defects in the genes COL4A3, COL4A4 and COL4A5, and Pierson syndrome, which is caused by variants in LAMB2. In addition, the GBM is affected by acquired autoimmune disorders and metabolic diseases such as diabetes mellitus. Current treatments for diseases associated with GBM involvement aim to reduce intraglomerular pressure and to treat the underlying cause where possible. As our understanding about the maintenance and turnover of the GBM improves, therapies to replace GBM components or to stimulate GBM repair could translate into new therapies for patients with GBM-associated disease.
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19
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Wrede C, Hegermann J, Mühlfeld C. Novel cell contact between podocyte microprojections and parietal epithelial cells analyzed by volume electron microscopy. Am J Physiol Renal Physiol 2020; 318:F1246-F1251. [PMID: 32249613 DOI: 10.1152/ajprenal.00097.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Podocytes are highly specialized cells with a clear cell polarity. It is known that in health and disease, microvilli protrude from the apical surface of the podocytes into the urinary space. As a basis to better understand the podocyte microprojections/microvilli, the present study analyzed their spatial localization, extension, and contact site with parietal epithelial cells (PECs). Using different electron microscopic (EM) techniques, we analyzed renal corpuscles of healthy young adult male C57BL/6 mice fixed by vascular perfusion. Serial block-face scanning EM was used to visualize entire corpuscles, focused ion beam scanning EM was performed to characterize microprojection/microvilli-rich regions at higher magnification, and transmission EM of serial sections was used to analyze the contact zone between podocyte microprojections and PECs. Numerous microprojections originating from the primary processes of podocytes were present in the urinary space in all regions of the corpuscle. They often reached the apical surface of the PEC but did not make junctional contacts. At high resolution, it was observed that the glycocalyx of both cells was in contact. Depending on the distance between podocytes and PECs, these microprojections had a stretched or coiled state. The present study shows that microprojections/microvilli of podocytes are a physiological feature of healthy mouse kidneys and are frequently in contact with the apical surface of PECs, thus spanning the urinary space. It is proposed that podocyte microprojections serve mechanosensory or communicative functions between podocytes and PECs.
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Affiliation(s)
- Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
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20
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Three-dimensional imaging of podocyte ultrastructure using FE-SEM and FIB-SEM tomography. Cell Tissue Res 2019; 379:245-254. [DOI: 10.1007/s00441-019-03118-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 09/26/2019] [Indexed: 11/25/2022]
Abstract
AbstractPodocytes are specialized epithelial cells used for glomerular filtration in the kidney. They can be divided into the cell body, primary process and foot process. Here, we describe two useful methods for the three-dimensional(3D) visualization of these subcellular compartments in rodent podocytes. The first method, field-emission scanning electron microscopy (FE-SEM) with conductive staining, is used to visualize the luminal surface of numerous podocytes simultaneously. The second method, focused-ion beam SEM (FIB-SEM) tomography, allows the user to obtain serial images from different depths of field, or Z-stacks, of the glomerulus. This allows for the 3D reconstruction of podocyte ultrastructure, which can be viewed from all angles, from a single image set. This is not possible with conventional FE-SEM. The different advantages and disadvantages of FE-SEM and FIB-SEM tomography compensate for the weaknesses of the other. The combination renders a powerful approach for the 3D analysis of podocyte ultrastructure. As a result, we were able to identify a new subcellular compartment of podocytes, “ridge-like prominences” (RLPs).
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21
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Wang L, Law HKW. Immune Complexes Impaired Glomerular Endothelial Cell Functions in Lupus Nephritis. Int J Mol Sci 2019; 20:ijms20215281. [PMID: 31652980 PMCID: PMC6862593 DOI: 10.3390/ijms20215281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 10/05/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022] Open
Abstract
Lupus nephritis (LN) is one of the most common and severe complications of lupus. However, the mechanisms for renal damage have not been well elucidated. There are evidences show that glomerular endothelial cells (GECs) are damaged in LN. Immune complexes can deposit in subendothelial area and could affect GEC functions. In the present study, we used heat-aggregated gamma globulin (HAGG) to simulate immune complexes and investigated their effects on GEC functions. Our results revealed that HAGG impaired different aspect of the GEC functions. HAGG changed cell morphology, upregulated the expression of active caspase-3, inhibited angiogenesis, and increased NO production in GECs. These results provide new clues for the mechanisms of renal damage and the pathology of LN.
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Affiliation(s)
- Linlin Wang
- Department of Health Technology and Informatics, Faculty of Health and Social Science, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
| | - Helen Ka Wai Law
- Department of Health Technology and Informatics, Faculty of Health and Social Science, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
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22
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Smith D, Starborg T. Serial block face scanning electron microscopy in cell biology: Applications and technology. Tissue Cell 2019; 57:111-122. [DOI: 10.1016/j.tice.2018.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/22/2018] [Accepted: 08/26/2018] [Indexed: 10/28/2022]
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23
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Pullman JM. New Views of the Glomerulus: Advanced Microscopy for Advanced Diagnosis. Front Med (Lausanne) 2019; 6:37. [PMID: 30899761 PMCID: PMC6416220 DOI: 10.3389/fmed.2019.00037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
New technologies are ready to revolutionize glomerular imaging and significantly improve or replace immunofluorescence and electron microscopy, which have driven research and diagnosis of glomerular diseases for over 50 years. Advanced forms of transmission and scanning electron microscopy have revealed the detailed spatial relationships of the glomerular basement membrane, podocytes, and endothelial cells. These may be overshadowed by super resolution microscopy (SRM), which combines the advantages of immunofluorescence and electron microscopy, offers high resolution identification of specific molecules, and images large, physiologically relevant volumes of the glomerulus. Rapidity, ease of use and low cost with some types of SRM make them potentially suitable for routine diagnosis. SRM visualizes structures below the classical diffraction limit of conventional light microscopy by adding a time variable to either the illumination of the specimen, or to the fluorescence signal emitted by it. Ensemble techniques vary illumination and include Structured Illumination Microscopy (SIM) and Stimulation Emission Depletion Microscopy (STED). Single molecule localization techniques vary the light emission by fluorescence labels in the specimen, and include Photoactivated Localization Microscopy (PALM) and Stochastic Optical Reconstruction Microscopy (STORM). Technologies such as expansion microscopy and genetic labeling can also create effective super resolution imaging by non-optical, specialized preparation techniques. All technologies require dark field fluorescence and some require computer image analysis and reconstruction. Replicating successful application in other areas of biology, SIM, STED, and STORM have visualized normal and nephrotic disease podocytes, and have confirmed their appearances to be similar to those seen by electron microscopy, but with added new information on cell configuration and protein localization. STORM has also localized podocyte cytoskeleton and adhesion proteins, and glomerular basement membrane proteins at a resolution never before possible. These pioneering efforts show the promise of super resolution microscopy, and lay the groundwork for future study and new diagnostic tools for glomerular diseases.
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Affiliation(s)
- James M Pullman
- Division of Anatomic Pathology, Department of Pathology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, United States
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24
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Smith RJH, Appel GB, Blom AM, Cook HT, D'Agati VD, Fakhouri F, Fremeaux-Bacchi V, Józsi M, Kavanagh D, Lambris JD, Noris M, Pickering MC, Remuzzi G, de Córdoba SR, Sethi S, Van der Vlag J, Zipfel PF, Nester CM. C3 glomerulopathy - understanding a rare complement-driven renal disease. Nat Rev Nephrol 2019; 15:129-143. [PMID: 30692664 PMCID: PMC6876298 DOI: 10.1038/s41581-018-0107-2] [Citation(s) in RCA: 196] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The C3 glomerulopathies are a group of rare kidney diseases characterized by complement dysregulation occurring in the fluid phase and in the glomerular microenvironment, which results in prominent complement C3 deposition in kidney biopsy samples. The two major subgroups of C3 glomerulopathy - dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) - have overlapping clinical and pathological features suggestive of a disease continuum. Dysregulation of the complement alternative pathway is fundamental to the manifestations of C3 glomerulopathy, although terminal pathway dysregulation is also common. Disease is driven by acquired factors in most patients - namely, autoantibodies that target the C3 or C5 convertases. These autoantibodies drive complement dysregulation by increasing the half-life of these vital but normally short-lived enzymes. Genetic variation in complement-related genes is a less frequent cause. No disease-specific treatments are available, although immunosuppressive agents and terminal complement pathway blockers are helpful in some patients. Unfortunately, no treatment is universally effective or curative. In aggregate, the limited data on renal transplantation point to a high risk of disease recurrence (both DDD and C3GN) in allograft recipients. Clinical trials are underway to test the efficacy of several first-generation drugs that target the alternative complement pathway.
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Affiliation(s)
- Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories and the Departments of Internal Medicine and Pediatrics (Divisions of Nephrology), Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| | - Gerald B Appel
- Department of Nephrology, Columbia University, New York, NY, USA
| | - Anna M Blom
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - H Terence Cook
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - Vivette D D'Agati
- Department of Pathology, Renal Pathology Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Fadi Fakhouri
- Department of Nephrology and Immunology, Centre Hospitalier et Universitaire de Nantes, Nantes, France
| | - Véronique Fremeaux-Bacchi
- Service de Néphrologie-Transplantation Adulte, Hôpital Necker-Enfants Malades, Université Paris Descartes, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University and the MTA-SE Research Group of Immunology and Haematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - David Kavanagh
- Newcastle University, Institute of Genetic Medicine, International Centre for Life, Central Parkway, Newcastle upon Tyne, UK
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marina Noris
- Istituto di Ricerche Farmacologiche (IRCCS) 'Mario Negri', Clinical Research Centre for Rare Diseases 'Aldo e Cele Daccò', Ranica, Bergamo, Italy
| | | | - Giuseppe Remuzzi
- Istituto di Ricerche Farmacologiche (IRCCS) 'Mario Negri', Clinical Research Centre for Rare Diseases 'Aldo e Cele Daccò', Ranica, Bergamo, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- Unit of Nephrology and Dialysis, Azienda Socio-Sanitaria Territoriale (ASST) Papa Giovanni XXIII, Bergamo, Italy
| | - Santiago Rodriguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Johan Van der Vlag
- Department of Nephrology, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Peter F Zipfel
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories and the Departments of Internal Medicine and Pediatrics (Divisions of Nephrology), Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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Voinova M, Repin N, Sokol E, Tkachuk B, Gorelik L. Physical Processes in Polymeric Filters Used for Dialysis. Polymers (Basel) 2019; 11:E389. [PMID: 30960373 PMCID: PMC6473866 DOI: 10.3390/polym11030389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/06/2019] [Accepted: 02/12/2019] [Indexed: 01/03/2023] Open
Abstract
The key physical processes in polymeric filters used for the blood purification include transport across the capillary wall and the interaction of blood cells with the polymer membrane surface. Theoretical modeling of membrane transport is an important tool which provides researchers with a quantification of the complex phenomena involved in dialysis. In the paper, we present a dense review of the most successful theoretical approaches to the description of transport across the polymeric membrane wall as well as the cell⁻polymer surface interaction, and refer to the corresponding experimental methods while studying these phenomena in dialyzing filters.
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Affiliation(s)
- Marina Voinova
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
- Department of Industrial and Biomedical Electronics, Kharkiv Polytechnical Institute, National Technical University, 61002 Kharkov, Ukraine.
| | - Nikolay Repin
- Department of Cryomorphology, Institute for Problems of Cryobiology and Cryomedicine, 61015 Kharkov, Ukraine.
| | - Evgen Sokol
- Department of Industrial and Biomedical Electronics, Kharkiv Polytechnical Institute, National Technical University, 61002 Kharkov, Ukraine.
| | - Bogdan Tkachuk
- Department of Hemodialysis, Municipal Noncommercial Enterprise of Kharkiv Regional Council "Regional Medical Clinical Center of Urology and Nephrology n.a. V.I. Shapoval", 61037 Kharkov, Ukraine.
| | - Leonid Gorelik
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden.
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Siegerist F, Endlich K, Endlich N. Novel Microscopic Techniques for Podocyte Research. Front Endocrinol (Lausanne) 2018; 9:379. [PMID: 30050501 PMCID: PMC6050355 DOI: 10.3389/fendo.2018.00379] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/22/2018] [Indexed: 01/16/2023] Open
Abstract
Together with endothelial cells and the glomerular basement membrane, podocytes form the size-specific filtration barrier of the glomerulus with their interdigitating foot processes. Since glomerulopathies are associated with so-called foot process effacement-a severe change of well-formed foot processes into flat and broadened processes-visualization of the three-dimensional podocyte morphology is a crucial part for diagnosis of nephrotic diseases. However, interdigitating podocyte foot processes are too narrow to be resolved by classic light microscopy due to Ernst Abbe's law making electron microscopy necessary. Although three dimensional electron microscopy approaches like serial block face and focused ion beam scanning electron microscopy and electron tomography allow volumetric reconstruction of podocytes, these techniques are very time-consuming and too specialized for routine use or screening purposes. During the last few years, different super-resolution microscopic techniques were developed to overcome the optical resolution limit enabling new insights into podocyte morphology. Super-resolution microscopy approaches like three dimensional structured illumination microscopy (3D-SIM), stimulated emission depletion microscopy (STED) and localization microscopy [stochastic optical reconstruction microscopy (STORM), photoactivated localization microscopy (PALM)] reach resolutions down to 80-20 nm and can be used to image and further quantify podocyte foot process morphology. Furthermore, in vivo imaging of podocytes is essential to study the behavior of these cells in situ. Therefore, multiphoton laser microscopy was a breakthrough for in vivo studies of podocytes in transgenic animal models like rodents and zebrafish larvae because it allows imaging structures up to several hundred micrometer in depth within the tissue. Additionally, along with multiphoton microscopy, lightsheet microscopy is currently used to visualize larger tissue volumes and therefore image complete glomeruli in their native tissue context. Alongside plain visualization of cellular structures, atomic force microscopy has been used to study the change of mechanical properties of podocytes in diseased states which has been shown to be a culprit in podocyte maintenance. This review discusses recent advances in the field of microscopic imaging and demonstrates their currently used and other possible applications for podocyte research.
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Affiliation(s)
| | | | - Nicole Endlich
- Institute for Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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27
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Bates DO, Beazley-Long N, Benest AV, Ye X, Ved N, Hulse RP, Barratt S, Machado MJ, Donaldson LF, Harper SJ, Peiris-Pages M, Tortonese DJ, Oltean S, Foster RR. Physiological Role of Vascular Endothelial Growth Factors as Homeostatic Regulators. Compr Physiol 2018; 8:955-979. [PMID: 29978898 DOI: 10.1002/cphy.c170015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The vascular endothelial growth factor (VEGF) family of proteins are key regulators of physiological systems. Originally linked with endothelial function, they have since become understood to be principal regulators of multiple tissues, both through their actions on vascular cells, but also through direct actions on other tissue types, including epithelial cells, neurons, and the immune system. The complexity of the five members of the gene family in terms of their different splice isoforms, differential translation, and specific localizations have enabled tissues to use these potent signaling molecules to control how they function to maintain their environment. This homeostatic function of VEGFs has been less intensely studied than their involvement in disease processes, development, and reproduction, but they still play a substantial and significant role in healthy control of blood volume and pressure, interstitial volume and drainage, renal and lung function, immunity, and signal processing in the peripheral and central nervous system. The widespread expression of VEGFs in healthy adult tissues, and the disturbances seen when VEGF signaling is inhibited support this view of the proteins as endogenous regulators of normal physiological function. This review summarizes the evidence and recent breakthroughs in understanding of the physiology that is regulated by VEGF, with emphasis on the role they play in maintaining homeostasis. © 2017 American Physiological Society. Compr Physiol 8:955-979, 2018.
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Affiliation(s)
- David O Bates
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | | | - Andrew V Benest
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Xi Ye
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Nikita Ved
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Richard P Hulse
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Shaney Barratt
- Academic Respiratory Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
| | - Maria J Machado
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham, United Kingdom
| | - Lucy F Donaldson
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Steven J Harper
- School of Physiology, Pharmacology & Neuroscience, Medical School, University of Bristol, Bristol, United Kingdom
| | - Maria Peiris-Pages
- Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom
| | - Domingo J Tortonese
- Centre for Comparative and Clinical Anatomy, University of Bristol, Bristol, United Kingdom
| | - Sebastian Oltean
- Institute of Biomedical & Clinical Sciences, University of Exeter Medical School, Exeter, United Kingdom
| | - Rebecca R Foster
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom
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28
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Jin X, Cao X, Wang X, Jiang J, Wan J, Laliberté JF, Zhang Y. Three-Dimensional Architecture and Biogenesis of Membrane Structures Associated with Plant Virus Replication. FRONTIERS IN PLANT SCIENCE 2018; 9:57. [PMID: 29441085 PMCID: PMC5797596 DOI: 10.3389/fpls.2018.00057] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/11/2018] [Indexed: 05/20/2023]
Abstract
Positive-sense (+) RNA viruses represent the most abundant group of viruses and are dependent on the host cell machinery to replicate. One remarkable feature that occurs after (+) RNA virus entry into cells is the remodeling of host endomembranes, leading to the formation of viral replication factories. Recently, rapid progress in three-dimensional (3D) imaging technologies, such as electron tomography (ET) and focused ion beam-scanning electron microscopy (FIB-SEM), has enabled researchers to visualize the novel membrane structures induced by viruses at high resolution. These 3D imaging technologies provide new mechanistic insights into the viral infection cycle. In this review, we summarize the latest reports on the cellular remodeling that occurs during plant virus infection; in particular, we focus on studies that provide 3D architectural information on viral replication factories. We also outline the mechanisms underlying the formation of these membranous structures and discuss possible future research directions.
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Affiliation(s)
- Xuejiao Jin
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiuling Cao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xueting Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jun Jiang
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
| | - Juan Wan
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
| | - Jean-François Laliberté
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
- *Correspondence: Jean-François Laliberté
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
- Yongliang Zhang
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Abstract
The last 5 years have witnessed tremendous advances in both light- and electron-microscopic techniques in the biomedical sciences. Application of these new cutting-edge methods to glomerular biology has advanced considerably and, in part, completed our endeavor to draw a detailed map of the glomerular tuft. The scope of this review is to illustrate these new insights within both the morphometry of podocyte cells and the architecture of the glomerular filtration barrier and to assess whether these findings have indeed had an impact on our biological understanding of glomerular function.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine IV, Medical Center and Faculty of Medicine, University of Freiburg, Breisacherstrasse 66, 79106, Freiburg, Germany. .,III. Medical Clinic, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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30
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Kriz W, Lemley KV. Mechanical challenges to the glomerular filtration barrier: adaptations and pathway to sclerosis. Pediatr Nephrol 2017; 32:405-417. [PMID: 27008645 DOI: 10.1007/s00467-016-3358-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 11/30/2022]
Abstract
Podocytes are lost as viable cells by detachment from the glomerular basement membrane (GBM), possibly due to factors such as pressure and filtrate flow. Distension of glomerular capillaries in response to increased pressure is limited by the elastic resistance of the GBM. The endothelium and podocytes adapt to changes in GBM area. The slit diaphragm (SD) seems to adjust by shuttling SD components between the SD and the adjacent foot processes (FPs), resulting in changes in SD area that parallel those in perfusion pressure.Filtrate flow tends to drag podocytes towards the urinary orifice by shear forces, which are highest within the filtration slits. The SD represents an atypical adherens junction, mechanically interconnecting the cytoskeleton of opposing FPs and tending to balance the shear forces.If under pathological conditions, increased filtrate flows locally overtax the attachment of FPs, the SDs are replaced by occluding junctions that seal the slits and the attachment of podocytes to the GBM is reinforced by FP effacement. Failure of these temporary adaptive mechanisms results in a steady process of podocyte detachment due to uncontrolled filtrate flows through bare areas of the GBM and, subsequently, the labyrinthine subpodocyte spaces, presenting as pseudocysts. In our view, shear stress due to filtrate flow-not capillary hydrostatic pressure-is the major challenge to the attachment of podocytes to the GBM.
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Affiliation(s)
- Wilhelm Kriz
- Department of Neuroanatomy, Medical Faculty Mannheim, University of Heidelberg, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Germany.
| | - Kevin V Lemley
- Division of Nephrology, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Pediatrics, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
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31
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Pinteala T, Chiriac AE, Rosca I, Larese Filon F, Pinteala M, Chiriac A, Podoleanu C, Stolnicu S, Coros MF, Coroaba A. Nail Damage (Severe Onychodystrophy) Induced by Acrylate Glue: Scanning Electron Microscopy and Energy Dispersive X-Ray Investigations. Skin Appendage Disord 2016; 2:137-142. [PMID: 28232921 DOI: 10.1159/000450791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/13/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques have been used in various fields of medical research, including different pathologies of the nails; however, no studies have focused on obtaining high-resolution microscopic images and elemental analysis of disorders caused by synthetic nails and acrylic adhesives. METHODS Damaged/injured fingernails caused by the use of acrylate glue and synthetic nails were investigated using SEM and EDX methods. RESULTS SEM and EDX proved that synthetic nails, acrylic glue, and nails damaged by contact with acrylate glue have a different morphology and different composition compared to healthy human nails. CONCLUSIONS SEM and EDX analysis can give useful information about the aspects of topography (surface sample), morphology (shape and size), hardness or reflectivity, and the elemental composition of nails.
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Affiliation(s)
- Tudor Pinteala
- Grigore T. Popa University of Medicine and Pharmacy, Iasi, Romania
| | | | - Irina Rosca
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, Institute of Macromolecular Chemistry Petru Poni, Iasi, Romania
| | - Francesca Larese Filon
- Dipartimento di Scienze di Medicina Pubblica, Università degli Studi di Trieste, Trieste, Italy
| | - Mariana Pinteala
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, Institute of Macromolecular Chemistry Petru Poni, Iasi, Romania
| | - Anca Chiriac
- Department of Dermatology, Nicolina Medical Center, Iasi, Romania; Department of Dermato-Physiology, Apollonia University, Iasi, Romania
| | - Cristian Podoleanu
- Cardiology Clinic, University of Medicine and Pharmacy of Targu-Mures, Tîrgu Mureș, Romania
| | - Simona Stolnicu
- Pathology Department, University of Medicine and Pharmacy of Targu-Mures, Tîrgu Mureș, Romania
| | - Marius Florin Coros
- Surgery Department, University of Medicine and Pharmacy of Targu-Mures, Tîrgu Mureș, Romania
| | - Adina Coroaba
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, Institute of Macromolecular Chemistry Petru Poni, Iasi, Romania
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Kim AH, Suleiman H, Shaw AS. New approaches in renal microscopy: volumetric imaging and superresolution microscopy. Curr Opin Nephrol Hypertens 2016; 25:159-67. [PMID: 27023834 PMCID: PMC4910820 DOI: 10.1097/mnh.0000000000000220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Histologic and electron microscopic analysis of the kidney has provided tremendous insight into structures such as the glomerulus and nephron. Recent advances in imaging, such as deep volumetric approaches and superresolution microscopy, have the capacity to dramatically enhance our current understanding of the structure and function of the kidney. Volumetric imaging can generate images millimeters below the surface of the intact kidney. Superresolution microscopy breaks the diffraction barrier inherent in traditional light microscopy, enabling the visualization of fine structures. Here, we describe new approaches to deep volumetric and superresolution microscopy of the kidney. RECENT FINDINGS Rapid advances in lasers, microscopic objectives, and tissue preparation have transformed our ability to deep volumetric image the kidney. Innovations in sample preparation have allowed for superresolution imaging with electron microscopy correlation, providing unprecedented insight into the structures within the glomerulus. SUMMARY Technological advances in imaging have revolutionized our capacity to image both large volumes of tissue and the finest structural details of a cell. These new advances have the potential to provide additional profound observations into the normal and pathologic functions of the kidney.
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Affiliation(s)
- Alfred H.J. Kim
- Division of Rheumatology, Dept. of Internal Medicine, Washington University School of Medicine, Saint Louis, MO, USA
| | - Hani Suleiman
- Division of Immunobiology, Dept. of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Andrey S. Shaw
- Division of Immunobiology, Dept. of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA
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Abstract
Kidney glomeruli ultrafilter blood to generate urine and they are dysfunctional in a variety of kidney diseases. There are two key vascular growth factor families implicated in glomerular biology and function, namely the vascular endothelial growth factors (VEGFs) and the angiopoietins (Angpt). We present examples showing not only how these molecules help generate and maintain healthy glomeruli but also how they drive disease when their expression is dysregulated. Finally, we review how manipulating VEGF and Angpt signalling may be used to treat glomerular disease.
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34
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Hegermann J, Lünsdorf H, Ochs M, Haller H. Visualization of the glomerular endothelial glycocalyx by electron microscopy using cationic colloidal thorium dioxide. Histochem Cell Biol 2015; 145:41-51. [DOI: 10.1007/s00418-015-1378-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2015] [Indexed: 12/11/2022]
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35
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Golden MH. Nutritional and other types of oedema, albumin, complex carbohydrates and the interstitium - a response to Malcolm Coulthard's hypothesis: Oedema in kwashiorkor is caused by hypo-albuminaemia. Paediatr Int Child Health 2015; 35:90-109. [PMID: 25844980 DOI: 10.1179/2046905515y.0000000010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The various types of oedema in man are considered in relation to Starling's hypothesis of fluid movement from capillaries, with the main emphasis on nutritional oedema and the nephrotic syndrome in children. It is concluded that each condition has sufficient anomalous findings to render Starling's hypothesis untenable. The finding that the endothelial glycocalyx is key to control of fluid movement from and into the capillaries calls for complete revision of our understanding of oedema formation. The factors so far known to affect the function of the glycocalyx are reviewed. As these depend upon sulphated proteoglycans and other glycosaminoglycans, the argument is advanced that the same abnormalities will extend to the interstitial space and that kwashiorkor is fundamentally related to a defect in sulphur metabolism which can explain all the clinical features of the condition, including the formation of oedema.
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Key Words
- Albumin,
- Aldosterone,
- Angiotensin,
- Beriberi,
- Edema,
- Epidemic dropsy,
- Famine oedema,
- Glycocalyx,
- Glycosaminoglycans,
- Heart failure,
- Hunger oedema,
- Kwashiorkor,
- Malnutrition,
- Nephrotic syndrome,
- Oedema,
- Potassium deficiency,
- Pre-eclampsia,
- Protein-energy malnutrition,
- Proteoglycans,
- Renin,
- Salt,
- Severe acute malnutrition
- Vitamin E deficiency,
- War oedema,
- Water,
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36
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Starborg T, Kadler KE. Serial block face-scanning electron microscopy: A tool for studying embryonic development at the cell-matrix interface. ACTA ACUST UNITED AC 2015; 105:9-18. [DOI: 10.1002/bdrc.21087] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/18/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Tobias Starborg
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences; University of Manchester, Michael Smith Building; Oxford Road Manchester United Kingdom
| | - Karl E. Kadler
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences; University of Manchester, Michael Smith Building; Oxford Road Manchester United Kingdom
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37
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Three-dimensional architecture of podocytes revealed by block-face scanning electron microscopy. Sci Rep 2015; 5:8993. [PMID: 25759085 PMCID: PMC4355681 DOI: 10.1038/srep08993] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/12/2015] [Indexed: 12/31/2022] Open
Abstract
Block-face imaging is a scanning electron microscopic technique which enables easier acquisition of serial ultrastructural images directly from the surface of resin-embedded biological samples with a similar quality to transmission electron micrographs. In the present study, we analyzed the three-dimensional architecture of podocytes using serial block-face imaging. It was previously believed that podocytes are divided into three kinds of subcellular compartment: cell body, primary process, and foot process, which are simply aligned in this order. When the reconstructed podocytes were viewed from their basal side, the foot processes were branched from a ridge-like prominence, which was formed on the basal surface of the primary process and was similar to the usual foot processes in structure. Moreover, from the cell body, the foot processes were also emerged via the ridge-like prominence, as found in the primary process. The ridge-like prominence anchored the cell body and primary process to the glomerular basement membrane, and connected the foot processes to the cell body and primary process. In conclusion, serial block-face imaging is a powerful tool for clear understanding the three-dimensional architecture of podocytes through its ability to reveal novel structures which were difficult to determine by conventional transmission and scanning electron microscopes alone.
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38
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Bushong EA, Johnson DD, Kim KY, Terada M, Hatori M, Peltier ST, Panda S, Merkle A, Ellisman MH. X-ray microscopy as an approach to increasing accuracy and efficiency of serial block-face imaging for correlated light and electron microscopy of biological specimens. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:231-8. [PMID: 25392009 PMCID: PMC4415271 DOI: 10.1017/s1431927614013579] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The recently developed three-dimensional electron microscopic (EM) method of serial block-face scanning electron microscopy (SBEM) has rapidly established itself as a powerful imaging approach. Volume EM imaging with this scanning electron microscopy (SEM) method requires intense staining of biological specimens with heavy metals to allow sufficient back-scatter electron signal and also to render specimens sufficiently conductive to control charging artifacts. These more extreme heavy metal staining protocols render specimens light opaque and make it much more difficult to track and identify regions of interest (ROIs) for the SBEM imaging process than for a typical thin section transmission electron microscopy correlative light and electron microscopy study. We present a strategy employing X-ray microscopy (XRM) both for tracking ROIs and for increasing the efficiency of the workflow used for typical projects undertaken with SBEM. XRM was found to reveal an impressive level of detail in tissue heavily stained for SBEM imaging, allowing for the identification of tissue landmarks that can be subsequently used to guide data collection in the SEM. Furthermore, specific labeling of individual cells using diaminobenzidine is detectable in XRM volumes. We demonstrate that tungsten carbide particles or upconverting nanophosphor particles can be used as fiducial markers to further increase the precision and efficiency of SBEM imaging.
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Affiliation(s)
- Eric A Bushong
- 1Center for Research in Biological Systems,National Center for Microscopy and Imaging Research,University of California at San Diego,9500 Gilman Drive,La Jolla,CA 92093,USA
| | - Donald D Johnson
- 1Center for Research in Biological Systems,National Center for Microscopy and Imaging Research,University of California at San Diego,9500 Gilman Drive,La Jolla,CA 92093,USA
| | - Keun-Young Kim
- 1Center for Research in Biological Systems,National Center for Microscopy and Imaging Research,University of California at San Diego,9500 Gilman Drive,La Jolla,CA 92093,USA
| | - Masako Terada
- 2Carl Zeiss X-ray Microscopy Inc.,4385 Hopyard Rd #100,Pleasanton,CA 94588,USA
| | - Megumi Hatori
- 3Salk Institute for Biological Sciences,10010 N Torrey Pines Rd,La Jolla,CA 92037,USA
| | - Steven T Peltier
- 1Center for Research in Biological Systems,National Center for Microscopy and Imaging Research,University of California at San Diego,9500 Gilman Drive,La Jolla,CA 92093,USA
| | - Satchidananda Panda
- 3Salk Institute for Biological Sciences,10010 N Torrey Pines Rd,La Jolla,CA 92037,USA
| | - Arno Merkle
- 2Carl Zeiss X-ray Microscopy Inc.,4385 Hopyard Rd #100,Pleasanton,CA 94588,USA
| | - Mark H Ellisman
- 1Center for Research in Biological Systems,National Center for Microscopy and Imaging Research,University of California at San Diego,9500 Gilman Drive,La Jolla,CA 92093,USA
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39
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Kremer A, Lippens S, Bartunkova S, Asselbergh B, Blanpain C, Fendrych M, Goossens A, Holt M, Janssens S, Krols M, Larsimont JC, Mc Guire C, Nowack MK, Saelens X, Schertel A, Schepens B, Slezak M, Timmerman V, Theunis C, VAN Brempt R, Visser Y, Guérin CJ. Developing 3D SEM in a broad biological context. J Microsc 2015; 259:80-96. [PMID: 25623622 PMCID: PMC4670703 DOI: 10.1111/jmi.12211] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/28/2014] [Indexed: 12/25/2022]
Abstract
When electron microscopy (EM) was introduced in the 1930s it gave scientists their first look into the nanoworld of cells. Over the last 80 years EM has vastly increased our understanding of the complex cellular structures that underlie the diverse functions that cells need to maintain life. One drawback that has been difficult to overcome was the inherent lack of volume information, mainly due to the limit on the thickness of sections that could be viewed in a transmission electron microscope (TEM). For many years scientists struggled to achieve three-dimensional (3D) EM using serial section reconstructions, TEM tomography, and scanning EM (SEM) techniques such as freeze-fracture. Although each technique yielded some special information, they required a significant amount of time and specialist expertise to obtain even a very small 3D EM dataset. Almost 20 years ago scientists began to exploit SEMs to image blocks of embedded tissues and perform serial sectioning of these tissues inside the SEM chamber. Using first focused ion beams (FIB) and subsequently robotic ultramicrotomes (serial block-face, SBF-SEM) microscopists were able to collect large volumes of 3D EM information at resolutions that could address many important biological questions, and do so in an efficient manner. We present here some examples of 3D EM taken from the many diverse specimens that have been imaged in our core facility. We propose that the next major step forward will be to efficiently correlate functional information obtained using light microscopy (LM) with 3D EM datasets to more completely investigate the important links between cell structures and their functions.
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Affiliation(s)
- A Kremer
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - S Lippens
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - S Bartunkova
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - B Asselbergh
- VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - C Blanpain
- IRIBHM, Université Libre de Bruxelles, Brussels, B-1070, Belgium
| | - M Fendrych
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium.,Institute of Science and Technology (IST) Austria, Klosterneuburg, 3400, Austria
| | - A Goossens
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - M Holt
- Center for the Biology of Disease, VIB, Leuven, Belgium.,Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - S Janssens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Respiratory Medicine, Ghent University, Ghent, Belgium.,GROUP-ID Consortium, Ghent University and University Hospital, Ghent, Belgium
| | - M Krols
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - J-C Larsimont
- IRIBHM, Université Libre de Bruxelles, Brussels, B-1070, Belgium
| | - C Mc Guire
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - M K Nowack
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - X Saelens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - A Schertel
- Carl Zeiss Microscopy, GmbH, Oberkochen, Germany
| | - B Schepens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - M Slezak
- Center for the Biology of Disease, VIB, Leuven, Belgium
| | - V Timmerman
- VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - C Theunis
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - R VAN Brempt
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - Y Visser
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - C J Guérin
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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Neal CR. Podocytes … What's Under Yours? (Podocytes and Foot Processes and How They Change in Nephropathy). Front Endocrinol (Lausanne) 2015; 6:9. [PMID: 25755650 PMCID: PMC4337384 DOI: 10.3389/fendo.2015.00009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/15/2015] [Indexed: 12/25/2022] Open
Abstract
Most of the described structures of podocytes in health and disease have been inferred from light and electron microscopic studies of rodent models. The variation in filtration barrier features is measured on micrographs, the aim being statistical significance. This is the technical campaign waged against kidney disease but this approach can be misleading. The signaling cascades and connectivity of the podocyte and foot processes (FPs) are inferred from in vitro studies that at best blurr the reality of the in vivo state. This review will outline actin signaling connectivity and the key differences in the structural and functional domains squeezed into the FPs and the relationship of these domains to other parts of the podocyte. It covers the changes in podocytes during nephropathy concentrating on FP and finally proposes an alternative interpretation of FP ultrastructure derived from articles published over the last 60 years.
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Affiliation(s)
- Chris R. Neal
- Bristol Renal, University of Bristol, Bristol, UK
- *Correspondence: Chris R. Neal, Bristol Renal, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK e-mail:
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