Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy

Stem cell apoptosis exists widely in embryonic development, tissue regeneration, repair, aging and pathophysiology of disease. The molecular mechanism of stem cell apoptosis has been extensively investigated.*

However, alterations in biomechanics and nanomorphology have rarely been studied.*

In the research article “ Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy “ Xuelian Su, Haijing Zhou, Guangjie Bao, Jizeng Wang, Lin Liu, Qian Zheng, Manli Guo and Jinting Zhang establish an apoptosis model for bone marrow mesenchymal stem cells (BMSCs) and investigated in detail the reconstruction of the mechanical properties and nanomorphology of the cells.*

Atomic force microscopy (AFM), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), flow cytometry and Cell Counting Kit-8 analysis were applied to assess the cellular elasticity modulus, geometry, nanomorphology, cell surface ultrastructure, biological viability and early apoptotic signals (phosphatidylserine,PS).*

The results indicated that the cellular elastic modulus and volume significantly decreased, whereas the cell surface roughness obviously increased during the first 3 h of cytochalasin B (CB) treatment. Moreover, these alterations preceded the exposure of biological apoptotic signal PS.*

These findings suggested that cellular mechanical damage is connected with the apoptosis of BMSCs, and the alterations in mechanics and nanomorphology may be a sensitive index to detect alterations in cell viability during apoptosis. The results contribute to further understanding of apoptosis from the perspective of cell mechanics.*

NanoWorld PNP Silicon Nitride AFM probes of the PNP-DB type were used for the single-cell imaging with Atomic Force Microscopy and nanoindentation experiments described in this research article.*

Figure 4 from “Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy” by Xuelian Su et al.:
Surface topography of BMSCs captured by AFM at different times. Columns A–D indicated the height-measurement images, vertical deflection images, three-dimensional images and cross-sectional images, respectively. The bright area was the elevated part of the cell, where the nucleus was located(A,C). The untreated cells adhered well, and their surface was smooth. The texture of the F-actin bundles is clearly visible (B, 0 h). The surface of treated cells became increasingly rough, the periphery of the cells became irregular and the area of cell extension gradually decreased (A and B, 1 h, 3 h, respectively).
Figure 4 from “Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy” by Xuelian Su et al.:
Surface topography of BMSCs captured by AFM at different times. Columns A–D indicated the height-measurement images, vertical deflection images, three-dimensional images and cross-sectional images, respectively. The bright area was the elevated part of the cell, where the nucleus was located(A,C). The untreated cells adhered well, and their surface was smooth. The texture of the F-actin bundles is clearly visible (B, 0 h). The surface of treated cells became increasingly rough, the periphery of the cells became irregular and the area of cell extension gradually decreased (A and B, 1 h, 3 h, respectively).

*Xuelian Su, Haijing Zhou, Guangjie Bao, Jizeng Wang, Lin Liu, Qian Zheng, Manli Guo and Jinting Zhang
Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy
Biology Open (2020) 9, bio048108.
DOI: 10.1242/bio.048108

Please follow this external link to read the full article: https://bio.biologists.org/content/biolopen/9/3/bio048108.full.pdf

Open Access The article “ Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy “ by Xuelian Su, Haijing Zhou, Guangjie Bao, Jizeng Wang, Lin Liu, Qian Zheng, Manli Guo and Jinting Zhang is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP

Quantifying the adaptive mechanical behavior of living cells is essential for the understanding of their inner working and function.*

In their article “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” Mark Skamrahl, Huw Colin‐York, Liliana Barbieri and Marco Fritzsche use a combination of atomic force microscopy and fluorescence recovery after photobleaching is introduced which offers simultaneous quantification and direct correlation of molecule kinetics and mechanics in living cells.*

Simultaneous quantification of the relationship between molecule kinetics and cell mechanics may thus open up unprecedented insights into adaptive mechanobiological mechanisms of cells.*

For the AFM nanoindentation tests described in their publication the authors used NanoWorld Arrow-TL2 tipless cantilevers that were functionalized with a polystyrene bead with 5 µm radius.*

 Figure 1 a from “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” by M. Skamrahl et al.: 
 Establishment and calibration of the optomechanical AFM–FRAP platform. a) Schematic of the AFM–FRAP setup illustrating the experimental power of simultaneous quantification of molecule kinetics and cell mechanics
Figure 1 a from “Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP” by M. Skamrahl et al.:
Establishment and calibration of the optomechanical AFM–FRAP platform. a) Schematic of the AFM–FRAP setup illustrating the experimental power of simultaneous quantification of molecule kinetics and cell mechanics

*Mark Skamrahl, Huw Colin‐York, Liliana Barbieri, Marco Fritzsche
Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP
Small 2019, 1902202
DOI: https://doi.org/10.1002/smll.201902202

Please follow this external link to the full article https://onlinelibrary.wiley.com/doi/full/10.1002/smll.201902202

Open Access: The article « Simultaneous Quantification of the Interplay Between Molecular Turnover and Cell Mechanics by AFM–FRAP » by Mark Skamrahl, Huw Colin‐York, Liliana Barbieri and Marco Fritzsche is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other thirdparty material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics Studies

Atomic Force Microscopy is a powerful tool for evaluating cell mechanics.
In the recent article “Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics Studies” by Kellie Beicker, E. Timothy O’Brien III, Michael R. Falvo, Richard Superfine published in Nature Scientific Reports, the authors combine sideways imaging and a vertical light sheet illumination system integrated with AFM to achieve their results.

5 µm polystyrene beads attached to NanoWorld Arrow-TL1 tipless AFM probes were used.

igure 5 from Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics Studies: Membrane and nuclear displacements observed in response to force-rupture events between the AFM-tip and cell membrane. (a) Retraction portion of force-indentation curve with important points (A-G) identified. A, the point of zero force application to the cell, B-F, force-rupture peaks, and G, after bead releases from cell. (b) A closer examination of peaks E and F with sub-peaks of the E rupture event identified. No point is shown for E1 because this is the frame immediately following Peak E0. Inset indicates regions where displacement is measured between points E and F highlighted in green. These regions were determined through difference imaging using frames taken at E and F. (c) Regions of cell displacements determined through difference imaging highlighted in green for the sub-peaks indicated in (b). Yellow dashed lines indicate outline of AFM mounted bead. Scale bars = 5 um. NanoWorld Arrow-TL1 tipless AFM cantilevers were used.
Figure 5 from Beicker et. al Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics Studies: Membrane and nuclear displacements observed in response to force-rupture events between the AFM-tip and cell membrane. (a) Retraction portion of force-indentation curve with important points (A-G) identified. A, the point of zero force application to the cell, B-F, force-rupture peaks, and G, after bead releases from cell. (b) A closer examination of peaks E and F with sub-peaks of the E rupture event identified. No point is shown for E1 because this is the frame immediately following Peak E0. Inset indicates regions where displacement is measured between points E and F highlighted in green. These regions were determined through difference imaging using frames taken at E and F. (c) Regions of cell displacements determined through difference imaging highlighted in green for the sub-peaks indicated in (b). Yellow dashed lines indicate outline of AFM mounted bead. Scale bars = 5 um.

Kellie Beicker, E. Timothy O’Brien III, Michael R. Falvo, Richard Superfine
Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics
Studies
Nature Scientific Reports, volume 8, Article number: 1504 (2018)
DOI: https://doi.org/10.1038/s41598-018-19791-3

For the full article please follow this external link: https://rdcu.be/59FM

The article Beicker et. al, Vertical Light Sheet Enhanced Side-View Imaging for AFM Cell Mechanics Studies is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.