J. Pourati et al., IS CYTOSKELETAL TENSION A MAJOR DETERMINANT OF CELL DEFORMABILITY IN ADHERENT ENDOTHELIAL-CELLS, American journal of physiology. Cell physiology, 43(5), 1998, pp. 1283-1289
We tested the hypothesis that mechanical tension in the cytoskeleton (
CSK) is a major determinant of cell deformability. To confirm that ten
sion was present in adherent endothelial cells, we either cut or detac
hed them from their basal surface by a microneedle. After cutting or d
etachment, the cells rapidly retracted. This retraction was prevented,
however, if the CSK actin lattice was disrupted by cytochalasin D (Cy
to D). These results confirmed that there was preexisting CSK tension
in these cells and that the actin lattice was a primary stress-bearing
component of the CSK. Second, to determine the extent to which that p
reexisting CSK tension could alter cell deformability, we developed a
stretchable cell culture membrane system to impose a rapid mechanical
distension (and presumably a rapid increase in CSK tension) on adheren
t endothelial cells. Altered cell deformability was quantitated as the
shear stiffness measured by magnetic twisting cytometry. When membran
e strain increased 2.5 or 5%, the cell stiffness increased 15 and 30%,
respectively. Disruption of actin lattice with Cyto D abolished this
stretch-induced increase in stiffness, demonstrating that the increase
d stiffness depended on the integrity of the actin CSK. Permeabilizing
the cells with saponin and washing away ATP and Ca2+ did not inhibit
the stretch-induced stiffening of the cell. These results suggest that
the stretch-induced stiffening was primarily due to the direct mechan
ical changes in the forces distending the CSK but not to ATP-or Ca2+-d
ependent processes. Taken together, these results suggest preexisting
CSK tension is a major determinant of cell deformability in adherent e
ndothelial cells.