Amentoflavone enhances osteogenesis of human mesenchymal stem cells through JNK and p38 MAPK pathways

Amentoflavone is a bioflavonoid found in a variety of traditional Chinese medicines such as Gingko and Selaginella tamariscina. It has been reported that amentoflavone has anti-inflammatory, antioxidant, antiviral and anticancer effects. However, the effect of amentoflavone on osteogenic differentiation of human mesenchymal stem cells (hMSCs) has not been studied. In this study, we aim to explore the effect of amentoflavone on the proliferation and osteogenic differentiation of hMSCs. The results showed that amentoflavone significantly enhanced the proliferation, alkaline phosphatase (ALP) activity and mineralization in hMSCs. Western blot analysis revealed that the expression of runt-related transcription factor 2 and osterix proteins was upregulated in amentoflavone-treated hMSCs. Furthermore, we investigated the possible signaling pathways responsible for osteogenic differentiation of hMSCs by amentoflavone. We found that amentoflavone significantly increased the levels of phosphorylated JNK and p-p38. The amentoflavone-induced increases of ALP and mineralization were significantly diminished when the JNK and p38 MAPK pathways were blocked by selected inhibitors (SP600125, SB203580) in hMSCs. Furthermore, in vivo evidence indicated that amentoflavone protected against the dexamethasone-induced inhibition of osteoblast differentiation in tg(sp7:egfp) zebrafish larvae. Thus, we showed for the first time that amentoflavone improves the osteogenesis of hMSCs through the JNK and p38 MAPK pathway. Amentoflavone may be beneficial in treating bone-related disorders.