Figure 1.

Osteoblast-like phenotypes were induced in human fibroblasts cultured in osteogenic medium supplemented with ALK5 i II. (A) Human dermal fibroblasts (aHDFs) were seeded into 24-well plates and cultured in the complete medium or osteogenic medium supplemented with TGF-β receptor inhibitors or rTGF-β as indicated. After culturing for 21 days, cells were stained with Alizarin Red S. Macroscopic images (Upper) and staining intensities (OD₅₅₀) (Lower) are shown. (B) aHDFs and MSCs were seeded into 24-well plates (day 0) and cultured as in (A). Thirteen days later, cells were subjected to ALP staining (Bottom). On day 18, the cells were stained with Alizarin Red S. Macroscopic images (Middle) and staining intensities (OD₅₅₀) are shown (Top). (C) Cells were cultured as in (B) and RNA was subjected to the real time-RT-PCR analysis on day 18. Relative mRNA levels are plotted. Magnification of the images are x 1. Values are means ± S.D. n = 3 (A and B) or 4 (C). *P < 0.05 and **P < 0.01, vs. the aHDF cultured in osteogenic medium alone. N.D., no significant difference between the indicated groups.