FIG. 3.

BMP stimulates cytoskeletal tension. (A) Epifluorescence images of stress fibers in hMSCs plated at 3,000 (upper panels) or 20,000 (lower panels) cells/cm² in the absence (left panels, Control) or presence of BMP-2 (right panels, BMP, 100 ng/mL) for 1 h. (B) Quantification results of stress fiber formation in hMSCs plated at 3,000 or 20,000 cells/cm² in the absence or presence of BMP-2 (100 ng/mL) (*P<0.05 vs. paired control.). A.U. represents arbitrary unit. (C) Representative images of control (C), BMP-2 (100 ng/mL) (BMP) and BMP-2 plus Y27632 (25 μM) (BMP+Y27) treated hMSC on mPAD (red, mPAD; green, actin cytoskeleton; blue, nuclei). Plot of average traction force exerted on each underlying post were presented as mean±SEM of 3 independent experiments (*P<0.01 vs. C; ^#P<0.01 between BMP-2 and BMP-2+ Y27). Scale bar: 20 μm. (D) Fluorescence images and quantification plot of stress fibers in hMSCs plated at 3,000 cells/cm² and treated with Y27632 (10 μM) in the presence of BMP-2 (100 ng/mL) for 1 h. mPAD, microfabricated postarray detector. Color images available online at www.liebertonline.com/scd