Remanent cell traction force in renal vascular smooth muscle cells induced by integrin-mediated mechanotransduction

Balasubramanian L, Lo CM, Sham JS, Yip KP. Remanent cell traction force in renal vascular smooth muscle cells induced by integrin-mediated mechanotransduction. Am J Physiol Cell Physiol 304: C382-C391, 2013. First published January 16, 2013; doi:10.1152/ajpcell.00234.2012.-It was previously demonstrated in isolated renal vascular smooth muscle cells (VSMCs) that integrin-mediated mechanotransduction triggers intracellular Ca2+ mobilization, which is the hallmark of myogenic response in VSMCs. To test directly whether integrin-mediated mechanotransduction results in the myogenic response-like behavior in renal VSMCs, cell traction force microscopy was used to monitor cell traction force when the cells were pulled with fibronectin-coated or low density lipoprotein (LDL)-coated paramagnetic beads. LDL-coated beads were used as a control for nonintegrin-mediated mechanotransduction. Pulling with LDL-coated beads increased the cell traction force by 61 +/- 12% (9 cells), which returned to the prepull level after the pulling process was terminated. Pulling with noncoated beads had a minimal increase in the cell traction force (12 +/- 9%, 8 cells). Pulling with fibronectin-coated beads increased the cell traction force by 56 +/- 20% (7 cells). However, the cell traction force was still elevated by 23 +/- 14% after the pulling process was terminated. This behavior is analogous to the changes of vascular resistance in pressure-induced myogenic response, in which vascular resistance remains elevated after myogenic constriction. Fibronectin is a native ligand for alpha(5)beta(1)-integrins in VSMCs. Similar remanent cell traction force was found when cells were pulled with beads coated with beta(1)-integrin antibody (Ha2/5). Activation of beta(1)-integrin with soluble antibody also triggered variations of cell traction force and Ca2+ mobilization, which were abolished by the Src inhibitor. In conclusion, mechanical force transduced by alpha(5)beta(1)-integrins triggered a myogenic response-like behavior in isolated renal VSMCs.