Figure 5. Identification of Gdf6 as an osteogenic factor derived from young MSCs. (A) Representative images of ALP staining of differentiated MSCs. ALP activity was quantified as the percentage of ALP+ area and compared with that of old MSCs (n = 4). (B) TuD-miR-17/106 repressed miR-17/106 (n = 3). (C) Repression of miR-17/106 induced downregulation of Gdf6 (n = 3). (D) qPCR of Gdf6 and Bmp2/4 in young and old MSCs (n = 8). (E) Administration of recombinant Bmp2 promoted osteogenic differentiation in young but not old MSCs (n = 4). Results are expressed as means ± SEM. NS, p > 0.05; *p < 0.05.