Recombinant human transforming growth factor β1 (rhTGFβ1) blocks recombinant human bone morphogenic protein (rhBMP)-2-mediated and rhBMP-7-mediated Smad1/5/8 signaling in primary human osteoblasts. (A) Primary human osteoblasts (N = 4) infected with Ad5-BRE-Luc adenoviral particles (Smad1/5/8 reporter construct) were stimulated for 24, 48, 72 and 96 h with 50 ng/ml rhBMP-2 or rhBMP-7. Luciferase activity was measured in cell lysates (n = 6). The single dose rhBMP-2 and rhBMP-7 induced Smad1/5/8 signaling with a peak signal after 72 h. *P < 0.05; **P < 0.01; ***P < 0.001 as compared to untreated cells in the case of rhBMP-2. °°°P < 0.001 as compared to untreated cells in the case of rhBMP-7. (B) Repetition of the experiment in the presence or absence of 5 ng/ml rhTGFβ1 for 72 h. The addition of rhTGFβ1 (hatched bars) completely blocked rhBMP-2-mediated (light gray bars) and rhBMP-7-mediated (dark gray bars) Smad1/5/8 signaling. ***P < 0.001 as compared to untreated cells. °P < 0.05; °°°P < 0.001 as compared to the corresponding rhBMP-2 and rhBMP-7 treated cells.
Ehnert et al. BMC Medicine 2012 10:101 doi:10.1186/1741-7015-10-101