Immunoblotting was performed as described previously.10 (link) Whole-cell lysates were extracted by using RIPA lysis buffer (Beyotime). Equal amounts of total proteins were subjected to SDS-PAGE separation, followed by immunoblotting with specific antibodies. Anti-Collagen I and Runx2 antibodies were purchased from Cell Signaling Technology (Danvers, MA, USA). Anti-Smad7, p-Smad2/3, Smad2/3, and GAPDH antibodies were purchased from Santa Cruz Biotechnology (Dallas, TX, USA). Anti-Myc tag antibody was purchased from Sigma-Aldrich.