Over-activation of IL-6-STAT3 signaling inhibits β-catenin activity.

<p>Normal and osteoporotic BMSCs were induced to undergo osteogenesis. Zero, 1, 2, and 3 weeks after induction, total protein was harvested, and western blotting was carried out using an antibody against non-phospho (active) β-catenin <b>(A)</b>. Total RNA was harvested, and quantitative RT-PCR was carried out using primers for cyclin D1 <b>(B)</b>, Axin2 <b>(C),</b> and Dkk1 <b>(D)</b>. The results are expressed as the fold-change relative to normal BMSCs without induction. The data are shown as the mean±SD. Osteoporotic BMSCs were treated with LiCl to activate β-catenin <b>(E)</b>. An IL-6 neutralizing antibody and AG490 were used to block IL-6-STAT3 signaling <b>(F)</b>. shRNAs were used to silence IL-6 expression <b>(G)</b>. Normal BMSCs were treated with IWR-1 to inhibit β-catenin <b>(H)</b>. Total protein was harvested, and western blotting was carried out using antibodies against active β-catenin, IL-6, and pSTAT3. IL-6 was added to the medium <b>(I)</b>. Western blotting was performed using an antibody against active β-catenin. β-actin was used as an internal control. *: p<0.05, Pred <i>vs</i>. scrambled control.