Fig. 4.

P2Y₂R regulate ATP and FSS-induced changes cell stiffness in osteoblasts. Atomic Force Microscopy was used to determine the apparent stiffness of osteoblasts exposed to various treatments. A: under static conditions, the average cell stiffness was 1.06 kPa. Cell stiffness significantly increased by approximately fivefold in response to 1 μM LPA treatment and by approximately sixfold after 15 min of FSS (12 dyn/cm²). Inhibition of ROCK activation with 10 μM Y27632 treatment prevented changes in cell stiffness due to FSS. B: FSS-induced increase in cell stiffness was also dependent on activation of P2Y₂R. The rise in cell stiffness induced by ATP treatment and FSS were suppressed by siRNA-mediated knockdown of the P2Y₂R in MC3T3-E1 cells. In nontransfected ATP-treated cells, the apparent stiffness was approximately fourfold greater than compared with static control cells. ^aP value <0.05 compared with static control.