Abstract
In order to study how intracellular forces are transmitted to the extracellular matrix during cell contraction, we investigated the change in traction forces at focal adhesions (FAs) and morphological changes of FAs in porcine aortic smooth muscle cells (SMCs) during their contraction. SMCs were cultured on polydimethylsiloxane-based micropillar array substrates, and then the traction forces at individual FAs were measured during cell contraction induced with 10^<-4>M serotonin. The traction forces immediately increased after the administration of serotonin especially at cell periphery, and their direction converged gradually to the direction parallel to the cell major axis. Fluctuation of forces was observed at some pillars during cell contraction. Surface reflective interference contrast microscopy revealed that FAs increased their area during cell contraction, and aligned in a direction parallel to the cell major axis. These results suggest that FAs remodel themselves actively during smooth muscle contraction depending on the direction and strength of contractile forces.
