Collaboration between integrin β1 and BMP2 signaling promotes FSS-induced osteogenic differentiation of MC3T3-E1 cells.

<p>Expression of <i>ITGB1</i> gene was measured by qRT-PCR after FSS (A) with/without RGD peptide for 2 h pre-incubation or (B) <i>ITBG1</i> RNAi (si-<i>ITGB1</i>). (C) RDG pre-incubation and (D) si-<i>ITGB1</i> inhibited <i>BMP2</i> transcription induced by FSS. (E) RDG pre-incubation and (F) si-<i>ITGB1</i> suppressed BMP2 secretion induced by FSS. RGD and si-<i>ITGB1</i> repressed transcription of osteogenic differentiation markers including (G & H) <i>ALP</i>, (I & J) <i>RUNX2</i> and (K & L) <i>SP7</i>. (M) RGD and (N) si-<i>ITGB1</i> inhibited FSS-induced ALP activity. (O) RGD and (P) si-<i>ITGB1</i> canceled mineralization of ECM at day 12. (Q) Post-FSS treatment of dorsomorphin inhibited up-regulated transcription of intergrin β1. (R) si-<i>BMP2</i> abolished FSS-induced increase of ITGB1 transcription. (Scale bar: 50 µm. *, FSS group versus control group, or NC + FSS group versus NC group; #, FSS + RGD/DM group versus FSS group, or si-<i>ITGB1</i>/<i>BMP2</i> + FSS group versus si- <i>ITGB1</i>/<i>BMP2</i> group. Data were shown as means ± SD. <i>n</i> = 3. * and #, <i>P</i><0.05; ** and ##, <i>P</i><0.01; *** and ###, <i>P</i><0.001.).</p>