Blocking TCF transcriptional activity attenuates Bzβ-induced matrix mineralization by MSC differentiation. C3H10T1/2 cells seeded in 12-well plates were transfected with 0.5 mg/mL of empty vector (Ai,Bi), dominant negative TCF1 (dnTCF1) (Aii,Bii), or dnTCF4 (Aiii,Biii) plasmid DNA for 48 hours. The cells were cultured in the absence or presence of 1 nM Bzb for 21 days. Matrix mineralization staining (Ai-iii) or calcium staining (Bi-iii) was performed as described in “Matrix mineralization.” (C) Primary MSCs from patients with MM transfected with EV, dnTCF1, or dnTCF4 plasmid DNA were cultured in the presence of 1 nM Bzb for 21 days. Calcium deposition was analyzed by ARS. Results are mean plus or minus SD (n = 3). *P < .01, **P < .001 vs controls. An Olympus IMT2 inverted research microscope (Olympus) using an Olympus 40×/0.65 P was used. The fluorescent images were acquired using a SPOT camera (Diagnostic Instruments) Model: 2.21 and were processed with an Advanced STOP version 4.7 software (Diagnostic Instruments) and Adobe Photoshop CS2 version 9.02 software (Adobe Systems).