Figure 8D-G. Effect of MSDK on sOPG and sRANKL expression in osteoblasts grown in transwell co-cultures, layered co-cultures and hMSCs monocultures. Treatments effects on secreted OPG (sOPG) and RANKL (sRANKL) were measured by ELISA in (D) transwells and (E) monocultures. Mean concentrations (pg/mL) of (i) sOPG: sRANKL, (ii) sOPG and (iii) sRANKL in culture media were analyzed, normalized against Os-/MSDK and compared between groups. Treatment effects on RANKL processing were detected via western blot by measuring the mean osteoblast’s expression of (i) 25 KDa and (ii) 24 KDa RANKL fragments in (F) transwells; and (G) 24 KDa RANKL fragment in layered co-cultures. *=p<.05, **=p<.01 and ***=p<.001; One-way ANOVA followed by Bonferroni’s post-hoc multiple comparison t-test (n=6 per group).