Role of histone methyltransferase KMT2D in BMSC osteogenesis via AKT signaling

Understanding the precise mechanism of BMSC (bone marrow mesenchymal stem cell) osteogenesis is critical for metabolic bone diseases and bone reconstruction. The histone-lysine N-methyltransferase 2D (KMT2D) acts as an important methyltransferase related with congenital skeletal disorders, yet the function of KMT2D in osteogenesis was unclear. Here we found that KMT2D expression was decreased in BMSCs collected from ovariectomized mice. Moreover, during human BMSC differentiation under mineralization induction, the mRNA level of KMT2D was gradually elevated. After KMT2D knockdown, the in vitro osteogenic differentiation of BMSCs was inhibited, while the in vivo bone formation potential of BMSCs was attenuated. Further, in BMSCs, KMT2D knockdown reduced the level of phosphorylated protein kinase B (p-AKT). SC-79, a common activator of AKT signaling, reversed the suppressing influence of KMT2D knockdown on BMSCs differentiation towards osteoblast. These results indicate that the KMT2D-AKT pathway plays an essential role in the osteogenesis process of human BMSCs (hBMSCs), which might provide new avenues for the molecular medicine of bone diseases and regeneration.