Icariin induces MC3T3-E1 cell proliferation and differentiation via the BMP-2/Smads/Runx2 signal pathway

AbstractIcariin, the main active ingredient of Epimedium, has played an important role in bone anabolism. However, the molecular mechanism for this effect was not convincingly reported yet. In this paper, the role of icariin on cell morphology, viability, cell cycling and the activity of alkaline phosphatase (ALP) were studied, and the molecular mechanism of icariin induced osteogenic effect was also investigated. Icariin with different concentrations (10, 20 and 40 ng/ml) was used to modify the pre-osteoblastic MC3T3-E1 cells for 48, 72 and 96 h, and the proliferation, morphology, and the cell cycle of the cells were evaluated by Cell Counting Kit-8 (CCK-8), microscopy and flow cytometry, respectively. Bone morphogenic protein-2 (BMP-2), bone morphogenic protein receptor-2 (BMPR-2), Smad4, Smadl/5/8 proteins expression levels were obtained by Western blotting and the expression levels of runt-related transcription factor 2 (Runx2) mRNA was examined by reverse transcription-polymerase chain reaction (RT-PCR). In this study, we found that icariin could promote the proliferation and differentiation of MC3T3-E1 cells in a dose - and time-dependent manner. Icariin could stimulate the expression of the BMP-2, BMPR-2, Smad4 and Smadl/5/8 proteins. Furthermore, icariin could upregulate the expression of Runx2 mRNA. These results showed that icariin played an important role in upregulating BMP-2 expression to activate the BMP-2/Smads/Runx2 signal pathway for increasing both the proliferation and differentiation of the MC3T3-E1 cells. However, the osteogenic effects of icariin can be suppressed by the BMP-2 antagonist (Noggin). In conclusion, we demonstrate that icariin is an osteoinductive factor that exerts its osteogenic effect by regulating the BMP-2/Smads/Runx2 signal pathway in MC3T3-E1 cells.