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Shaebani MR, Stankevicins L, Vesperini D, Urbanska M, Flormann DAD, Terriac E, Gad AKB, Cheng F, Eriksson JE, Lautenschläger F. Effects of vimentin on the migration, search efficiency, and mechanical resilience of dendritic cells. Biophys J 2022; 121:3950-3961. [PMID: 36056556 PMCID: PMC9675030 DOI: 10.1016/j.bpj.2022.08.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/20/2022] [Accepted: 08/24/2022] [Indexed: 11/24/2022] Open
Abstract
Dendritic cells use amoeboid migration to pass through narrow passages in the extracellular matrix and confined tissue in search for pathogens and to reach the lymph nodes and alert the immune system. Amoeboid migration is a migration mode that, instead of relying on cell adhesion, is based on mechanical resilience and friction. To better understand the role of intermediate filaments in ameboid migration, we studied the effects of vimentin on the migration of dendritic cells. We show that the lymph node homing of vimentin-deficient cells is reduced in our in vivo experiments in mice. Lack of vimentin also reduces the cell stiffness, the number of migrating cells, and the migration speed in vitro in both 1D and 2D confined environments. Moreover, we find that lack of vimentin weakens the correlation between directional persistence and migration speed. Thus, vimentin-expressing dendritic cells move faster in straighter lines. Our numerical simulations of persistent random search in confined geometries verify that the reduced migration speed and the weaker correlation between the speed and direction of motion result in longer search times to find regularly located targets. Together, these observations show that vimentin enhances the ameboid migration of dendritic cells, which is relevant for the efficiency of their random search for pathogens.
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Affiliation(s)
- M Reza Shaebani
- Department of Theoretical Physics, Saarland University, Saarbrücken, Germany; Centre for Biophysics, Saarland University, Saarbrücken, Germany
| | - Luiza Stankevicins
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Doriane Vesperini
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Marta Urbanska
- Biotechnology Centre, Centre for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Daniel A D Flormann
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Emmanuel Terriac
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Annica K B Gad
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, United Kingdom; Centro de Química da Madeira, Universidade da Madeira, Funchal, Portugal
| | - Fang Cheng
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland; School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou, China
| | - John E Eriksson
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Franziska Lautenschläger
- Centre for Biophysics, Saarland University, Saarbrücken, Germany; Department of Experimental Physics, Saarland University, Saarbrücken, Germany.
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Flormann DAD, Schu M, Terriac E, Thalla D, Kainka L, Koch M, Gad AKB, Lautenschläger F. A novel universal algorithm for filament network tracing and cytoskeleton analysis. FASEB J 2021; 35:e21582. [PMID: 33835502 DOI: 10.1096/fj.202100048r] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/06/2021] [Accepted: 03/25/2021] [Indexed: 01/01/2023]
Abstract
The rapid development of advanced microscopy techniques over recent decades has significantly increased the quality of imaging and our understanding of subcellular structures, such as the organization of the filaments of the cytoskeleton using fluorescence and electron microscopy. However, these recent improvements in imaging techniques have not been matched by similar development of techniques for computational analysis of the images of filament networks that can now be obtained. Hence, for a wide range of applications, reliable computational analysis of such two-dimensional methods remains challenging. Here, we present a new algorithm for tracing of filament networks. This software can extract many important parameters from grayscale images of filament networks, including the mesh hole size, and filament length and connectivity (also known as Coordination Number). In addition, the method allows sub-networks to be distinguished in two-dimensional images using intensity thresholding. We show that the algorithm can be used to analyze images of cytoskeleton networks obtained using different advanced microscopy methods. We have thus developed a new improved method for computational analysis of two-dimensional images of filamentous networks that has wide applications for existing imaging techniques. The algorithm is available as open-source software.
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Affiliation(s)
- Daniel A D Flormann
- Department of Physics, Saarland University, Saarbruecken, Germany.,INM - Leibniz Institute for New Materials, Saarbruecken, Germany
| | - Moritz Schu
- Department of Physics, Saarland University, Saarbruecken, Germany
| | - Emmanuel Terriac
- INM - Leibniz Institute for New Materials, Saarbruecken, Germany
| | - Divyendu Thalla
- Department of Physics, Saarland University, Saarbruecken, Germany.,INM - Leibniz Institute for New Materials, Saarbruecken, Germany
| | - Lucina Kainka
- Department of Physics, Saarland University, Saarbruecken, Germany.,INM - Leibniz Institute for New Materials, Saarbruecken, Germany
| | - Marcus Koch
- INM - Leibniz Institute for New Materials, Saarbruecken, Germany
| | - Annica K B Gad
- Department of Oncology and Metabolism, The Medical School, Weston Park Cancer Centre, Sheffield, UK.,Centro de Química da Madeira, Universidade da Madeira, Funchal, Portugal
| | - Franziska Lautenschläger
- Department of Physics, Saarland University, Saarbruecken, Germany.,INM - Leibniz Institute for New Materials, Saarbruecken, Germany
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Schu M, Terriac E, Koch M, Paschke S, Lautenschläger F, Flormann DAD. Scanning electron microscopy preparation of the cellular actin cortex: A quantitative comparison between critical point drying and hexamethyldisilazane drying. PLoS One 2021; 16:e0254165. [PMID: 34234360 PMCID: PMC8263306 DOI: 10.1371/journal.pone.0254165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/21/2021] [Indexed: 11/18/2022] Open
Abstract
The cellular cortex is an approximately 200-nm-thick actin network that lies just beneath the cell membrane. It is responsible for the mechanical properties of cells, and as such, it is involved in many cellular processes, including cell migration and cellular interactions with the environment. To develop a clear view of this dense structure, high-resolution imaging is essential. As one such technique, electron microscopy, involves complex sample preparation procedures. The final drying of these samples has significant influence on potential artifacts, like cell shrinkage and the formation of artifactual holes in the actin cortex. In this study, we compared the three most used final sample drying procedures: critical-point drying (CPD), CPD with lens tissue (CPD-LT), and hexamethyldisilazane drying. We show that both hexamethyldisilazane and CPD-LT lead to fewer artifactual mesh holes within the actin cortex than CPD. Moreover, CPD-LT leads to significant reduction in cell height compared to hexamethyldisilazane and CPD. We conclude that the final drying procedure should be chosen according to the reduction in cell height, and so CPD-LT, or according to the spatial separation of the single layers of the actin cortex, and so hexamethyldisilazane.
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Affiliation(s)
- Moritz Schu
- Leibniz Institute for New Materials (INM), Saarland University, Saarbrücken, Saarland, Germany
- Center for Biophysics, Saarland University, Saarbrücken, Saarland, Germany
| | - Emmanuel Terriac
- Leibniz Institute for New Materials (INM), Saarland University, Saarbrücken, Saarland, Germany
| | - Marcus Koch
- Leibniz Institute for New Materials (INM), Saarland University, Saarbrücken, Saarland, Germany
| | - Stephan Paschke
- Department of General and Visceral Surgery, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Franziska Lautenschläger
- Leibniz Institute for New Materials (INM), Saarland University, Saarbrücken, Saarland, Germany
- Center for Biophysics, Saarland University, Saarbrücken, Saarland, Germany
| | - Daniel A. D. Flormann
- Leibniz Institute for New Materials (INM), Saarland University, Saarbrücken, Saarland, Germany
- Center for Biophysics, Saarland University, Saarbrücken, Saarland, Germany
- * E-mail:
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