Osteogenic differentiation of MSCs upon fisetin treatment. Fisetin treatment at 10 µM inhibits osteogenic differentiation (as determined by Alizarin Red S staining) and quantitative measurement (A,B). Transcriptional analysis of COL1A1 and YAP (C,D) and protein expression, and the ratio of COL1A1 and YAP to ACTIN (E) upon fisetin treatment as determined by quantitative RT-PCR and western blotting, respectively. The data presented in subfigure (B–E) were analyzed by Mann–Whitney U test. Bars indicate mean values ± standard deviation (SD) and asterisks indicate significant differences, * p < 0.05; ** p < 0.01; *** p < 0.001, n.s. = no significant difference.