Stress fiber and the mechanical states in a living endothelial cell

Abstract

We have assumed that stress fibers play a critical role in transmitting intracellular forces to mechanosensing sites. Magnitude of preexisting tension in a single stress fiber of endothelial cells was estimated on the basis of measurements of its preexisting stretching strain and tensile properties. Cultured endothelial cells expressing fluorescently labeled actin were treated with detergents to extract stress fibers. One end of a stress fiber was then dislodged from the substrate by using a microneedle, resulting in a shortening of the stress fiber due to a release of preexisting tension. Assuming that the shortened stress fibers reached its nonstress state, preexisting stretching strain was determined to be 0.24 on average. A tensile test of the isolated single stress fiber was conducted with a pair of cantilevers. The magnitude of the preexisting tension was estimated as around10 nN on average in living endothelial cells.