Effects of mechanical stress on cell adhesion: a possible mechanism for morphological changes.

The transmission of mechanical forces to cells is followed among all by biological signals related to changes in the assembly or disassembly of integrins associated linker proteins, such as vinculin. We applied for 3 hours 2% cyclic mechanical strain at the frequency of 1 Hz to human fibroblasts cultured on a deformable substrate; substrate deformation resulted to modify the number, length and area of vinculin positive focal adhesion contacts when compared to not stretched cells. The mechanism behind these morphological changes is related to Akt and RhoA roles in focal adhesion assembly. In the case of Akt and Rho inhibition, focal contacts disassembled only in presence of stretching mechanical stress, highlighting the role of mechanical stress on focal adhesion maturation in terms of multimolecolar assembly which from focal complexes leads to fibrillar adhesion.