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

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