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Integrin mediated mechanical stress modulates traction force in renal vascular smooth muscle cells
Author(s) -
Balasubramanian Lavanya,
Lo C.M.,
Dembo M.,
Sham J.S.K.,
Yip K.P.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a500-a
Subject(s) - traction (geology) , tractive force , vascular smooth muscle , mechanobiology , elastic modulus , biophysics , integrin , materials science , fibronectin , biomedical engineering , chemistry , anatomy , composite material , cell , smooth muscle , medicine , structural engineering , biology , paleontology , biochemistry , engineering
Previously we developed a system comprised of fibronectin‐coated paramagnetic beads (FN‐beads, 4.5 μm diameter) and an electromagnet to apply mechanical force to renal vascular smooth muscle cells (VSMCs) via integrins. We sought to determine whether integrin mediated mechanical stress increases the contractile force of renal VSMCs using traction force microscopy. Traction force imposed by VSMCs on a deformable substratum impregnated with fluorescent beads (0.2 μm diameter) was computed based on the deformation and the Young's modulus of the substratum. The deformation was measured by the displacement of fluorescent beads and the Young's modulus by atomic force microscopy. The mean traction force was 3469±751 dyne/cm 2 (n=12) under control conditions. It was reduced by 41±12% when FN‐beads (20 beads/cell) were deposited on the VSMCs, consistent with the notion that cell is a tensegrity structure. Magnetic pulling (for 5 min) of FN‐beads increased the traction force by 31±8%, which is an order of magnitude larger than the mechanical stress imposed. Moreover, the traction force was sustained above the pre‐pull baseline by 11±4% 2 min after the pulling was terminated. These observations suggest that integrin mediated mechanical stress induces contractile force in VSMCs, which lingers after the mechanical stress is abolished. Support: AHA Predoctoral Fellowship, NIH DK 60501.