Local mechanical properties measured by atomic force microscopy for cultured bovine endothelial cells exposed to shear stress

Sato, Masaaki; Nagayama, Kazuaki; Kataoka, Noriyuki; Sato, Masato; Hane, Kazuhiro

doi:10.1016/s0021-9290(99)00178-5

Cited by 225 publications

(160 citation statements)

References 13 publications

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“…27 Shear stress also leads to polarized adaptive changes in cell mechanics. 44,45 Taken together, such studies support a model of cellular mechanotransduction in which the global activation of signaling pathways by shear-forces are converted to local signaling events in discrete locations in cells by force amplification and force-induced directional biasing of signal propagation. Thus, there is a need for models which quantify how the unique architecture of endothelial cells can amplify forces from shear stress at discrete cellular locations.…”

Section: Introductionmentioning

confidence: 56%

Finite-Element Stress Analysis of a Multicomponent Model of Sheared and Focally-Adhered Endothelial Cells

et al. 2007

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Hemodynamic forces applied at the apical surface of vascular endothelial cells may be redistributed to and amplified at remote intracellular organelles and protein complexes where they are transduced to biochemical signals. In this study we sought to quantify the effects of cellular material inhomogeneities and discrete attachment points on intracellular stresses resulting from physiological fluid flow. Steady-state shear-and magnetic bead-induced stress, strain, and displacement distributions were determined from finite-element stress analysis of a cell-specific, multicomponent elastic continuum model developed from multimodal fluorescence images of confluent endothelial cell (EC) monolayers and their nuclei. Focal adhesion locations and areas were determined from quantitative total internal reflection fluorescence microscopy and verified using green fluorescence protein-focal adhesion kinase (GFP-FAK). The model predicts that shear stress induces small heterogeneous deformations of the endothelial cell cytoplasm on the order of <100 nm. However, strain and stress were amplified 10-100-fold over apical values in and around the high-modulus nucleus and near focal adhesions (FAs) and stress distributions depended on flow direction. The presence of a 0.4 μm glycocalyx was predicted to increase intracellular stresses by ~2-fold. The model of magnetic bead twisting rheometry also predicted heterogeneous stress, strain, and displacement fields resulting from material heterogeneities and FAs. Thus, large differences in moduli between the nucleus and cytoplasm and the juxtaposition of constrained regions (e.g. FAs) and unattached regions provide two mechanisms of stress amplification in sheared endothelial cells. Such phenomena may play a role in subcellular localization of early mechanotransduction events.

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Section: Introductionmentioning

confidence: 56%

Finite-Element Stress Analysis of a Multicomponent Model of Sheared and Focally-Adhered Endothelial Cells

et al. 2007

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“…Experiments concerned changes in cell stiffness upon increasing Ca 2+ concentration [939,940] or the cellular contractility [941]. Also, the effect of cell differentiation [942], cell division [943], shear stress [917,944], culture time [307], and cell spreading [945] has been studied. Deformability of endothelial cell was found to increase after contact with monocytes (considered to play a major role in the early stage of atherosclerosis) [946].…”

Section: Filled Polyelectrolyte Capsulesmentioning

confidence: 99%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,242

2,949

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“…Confluent ECs were either kept as static controls or subjected to a laminar shear stress in a rectangular flow channel system composed of a flow chamber, a roller pump, and two reservoirs (Sato et al, 2000). Under the Poiseuille flow and the Newtonian fluid, the two-dimensional Navier-Stokes equation and the equation of continuity in the rectangular channel are integrated to the following form:…”

Section: Shear Stress Experimentsmentioning

confidence: 99%

“…Also, since the stiffness of endothelial cells change in response to shear stress probably due to rearrangements of actin filaments (Sato et al, , 1996(Sato et al, , 2000Charras and Horton, 2002;Ohashi et al, 2002), the mechanical properties of nucleus might also be dependent on its mechanical environment. To test the hypotheses, the endothelial nucleus was isolated from the cells, and the resultant morphological changes were observed with fluorescence microscopy.…”

Section: Introductionmentioning

confidence: 99%

Flow-induced hardening of endothelial nucleus as an intracellular stress-bearing organelle

Deguchi

Maeda

Ohashi

et al. 2005

Journal of Biomechanics

129

104

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The mechanical contribution of nucleus in adherent cells to bearing intracellular stresses remains unclear. In this paper, the effects of fluid shear stress on morphology and elastic properties of endothelial nuclei were investigated. The morphological observation suggested that the nuclei in the cytoplasm were being vertically compressed under static conditions, whereas they were elongated and more compressed with a fluid shear stress of 2 Pa (20 dyn/cm 2 ) onto the cell. The elongated nuclei remained the shape even after they were isolated from the cells. The micropipette aspiration technique on the isolated nuclei revealed that the elastic modulus of elongated nuclei, 0.62 ± 0.15 kPa (n = 13, mean ± SD), was significantly higher than that of control nuclei, 0.42 ± 0.12 kPa (n = 11), suggesting that the nuclei remodeled their structure due to the shear stress. Based of these results and a transmission electron microscopy, a possibility of the nucleus as an intracellular compression-bearing organelle was proposed, which will impact interpretation of stress distribution in adherent cells.3

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Local mechanical properties measured by atomic force microscopy for cultured bovine endothelial cells exposed to shear stress

Cited by 225 publications

References 13 publications

Finite-Element Stress Analysis of a Multicomponent Model of Sheared and Focally-Adhered Endothelial Cells

Finite-Element Stress Analysis of a Multicomponent Model of Sheared and Focally-Adhered Endothelial Cells

Force measurements with the atomic force microscope: Technique, interpretation and applications

Flow-induced hardening of endothelial nucleus as an intracellular stress-bearing organelle

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