Fibronectin Fiber Extension Decreases Cell Spreading and Migration.

The extracellular matrix (ECM) is present in a range of molecular conformations and intermolecular arrangements. Fibronectin (Fn) molecules that constitute fibers within the ECM can exist in a variety of conformations that result from both mechanical stress and chemical factors such as allosteric binding partners. The long-standing hypothesis that conformational changes regulate the binding of cells to Fn fibers has only been tested for mutated molecules of Fn and has yet to be fully evaluated with Fn fibers. Using time-lapse microscopy we examined how mechanical extension of single fibers of Fn affects the adhesion and migration of endothelial cells. Using this single fiber adhesion technique, we show that high levels of mechanical strain applied to Fn fibers decreases the rates of both cell spreading and cell migration. These data indicate a fundamental cellular response to mechanical strain in the ECM that might have important implications for understanding how cells are recruited during tissue development and repair. J. Cell. Physiol. 231: 1728-1736, 2016.