TY - JOUR
T1 - Tensile properties of single stress fibers isolated from cultured vascular smooth muscle cells
AU - Deguchi, Shinji
AU - Ohashi, Toshiro
AU - Sato, Masaaki
N1 - Funding Information:
This work was supported in part by Tohoku University 21COE Program ‘‘Future Medical Engineering Based on Bio-nanotechnology’’, the Grants in Aid for Scientific Research (A) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan (#14208100), and the Sasakawa Scientific Research Grant from Japan Science Society.
PY - 2006
Y1 - 2006
N2 - Stress fibers (SFs), a contractile bundle of actin filaments, play a critical role in mechanotransduction in adherent cells; yet, the mechanical properties of SFs are poorly understood. Here, we measured tensile properties of single SFs by in vitro manipulation with cantilevers. SFs were isolated from cultured vascular smooth muscle cells with a combination of low ionic-strength extraction and detergent extraction and were stretched until breaking. The breaking force and the Young's modulus (assuming that SFs were isotropic) were, on average, 377 nN and 1.45 MPa, which were approximately 600-fold greater and three orders of magnitude lower, respectively, than those of actin filaments reported previously. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length in an ATP-independent manner after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN, which was comparable with the traction force level applied by adherent cells at single adhesion sites to maintain cell integrity. These results suggest that SFs can bear intracellular stresses that may affect overall cell mechanical properties and will impact interpretation of intracellular stress distribution and force-transmission mechanism in adherent cells.
AB - Stress fibers (SFs), a contractile bundle of actin filaments, play a critical role in mechanotransduction in adherent cells; yet, the mechanical properties of SFs are poorly understood. Here, we measured tensile properties of single SFs by in vitro manipulation with cantilevers. SFs were isolated from cultured vascular smooth muscle cells with a combination of low ionic-strength extraction and detergent extraction and were stretched until breaking. The breaking force and the Young's modulus (assuming that SFs were isotropic) were, on average, 377 nN and 1.45 MPa, which were approximately 600-fold greater and three orders of magnitude lower, respectively, than those of actin filaments reported previously. Strain-induced stiffening was observed in the force-strain curve. We also found that the extracted SFs shortened to approximately 80% of the original length in an ATP-independent manner after they were dislodged from the substrate, suggesting that SFs had preexisting strain in the cytoplasm. The force required for stretching the single SFs from the zero-stress length back to the original length was approximately 10 nN, which was comparable with the traction force level applied by adherent cells at single adhesion sites to maintain cell integrity. These results suggest that SFs can bear intracellular stresses that may affect overall cell mechanical properties and will impact interpretation of intracellular stress distribution and force-transmission mechanism in adherent cells.
KW - Cell mechanics
KW - Mechanical properties
KW - Mechanotransduction
KW - Smooth muscle cell
KW - Stress fiber
UR - http://www.scopus.com/inward/record.url?scp=33749077090&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33749077090&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2005.08.026
DO - 10.1016/j.jbiomech.2005.08.026
M3 - Article
C2 - 16216252
AN - SCOPUS:33749077090
VL - 39
SP - 2603
EP - 2610
JO - Journal of Biomechanics
JF - Journal of Biomechanics
SN - 0021-9290
IS - 14
ER -