RNA-sequencing and ChIP-sequencing in murine mesenchymal stem cells treated with Ezh2 inhibitor GSK126 or β-catenin siRNA

During mesenchymal stem cell (MSC) differentiation, both Wnt signaling and the development of a rigid cytoskeleton promote commitment to the osteoblastic over adipogenic lineage. β-catenin is thought to play a critical role in Wnt effects. We show that β-catenin was additive with cytoskeletal signals to prevent adipogenesis, and β-catenin knockdown promoted adipogenesis even when the actin cytoskeleton was depolymerized. β-catenin also prevented osteoblast commitment in a cytoskeletal-independent manner, with β-catenin knockdown enhancing lineage commitment. Chip-seq showed that β-catenin associated with the promoter of EZH2, a key component of the PRC2 complex that governs genome methylation. Knocking down β-catenin lowered EZH2 levels and H3K27me3 at osteogenic loci. Further, when EZH2 was inhibited, β-catenin ’s anti-differentiation effects were lost. These results indicate that regulating EZH2 activity is key to β-catenin effects on MSC to preserve MSC multipotentiality.