Fibroblast Growth Factor-2 Primes Human Mesenchymal Stem Cells for Enhanced Chondrogenesis
Figure 6
FGF-2 enhances hMSC CG partially through a Sox9-mediated mechanism.
(A) RNAi experiments were performed to knockdown Sox9 expression. Human MSCs were transfected with siRNA targeted to Sox9 or non-targeting siRNA. 24 hours after transfection, hMSCs received FGF-2, and 72 hours after transfection, hMSCs were differentiated into the chondrogenic lineage in pellet culture. Sox9 knockdown was verified 48 and 72 hours after transfection by gene and protein analysis, respectively. (B) Western blot analysis showed that Sox9 levels were lower in both FGF-2- (+) and non-FGF-2-treated (−) hMSCs transfected with Sox9 siRNA compared to untransfected and non-targeting siRNA-transfected hMSCs. With each treatment, FGF-2 increased Sox9 levels. (C) After transfected hMSCs were differentiated into the chondrogenic lineage, real-time RT-PCR analysis showed that knockdown of Sox9 expression did not result in a concomitant decrease in Col II gene expression 7 and 21 days after pellet formation. However, FGF-2 pretreatment led to a significant increase in Col II gene expression in untransfected and Sox9 siRNA-transfected hMSCs.
