High water-soluble curcuminoids-rich extract regulates osteogenic differentiation of MC3T3-E1 cells:Involvement of Wnt/β-catenin and BMP signaling pathway

Objective:The present study aimed to evaluate the effect of a high water-soluble curcuminoids-rich extract(CRE)in a solid dispersion form(CRE-SD)using polyvinylpyrrolidone K30 on osteogenic induction of MC3T3-E1 cells.Methods:CRE was pre-purified using a microwave assisted extraction couple with a Diaion;HP-20 column chromatography.The osteoblastic cell proliferation and differentiation potentials of CRE-SD in MC3T3-E1 cells were tested by cell viability,alkaline phosphatase(ALP)activity,and Alizarin red S activity assays.The m RNA expressions of osteoblast-specific genes and underline mechanisms were assessed by a real time PCR and western blot analysis.Results:CRE-SD 50μg/m L increased alkaline phosphatase(ALP)activity,an early differentiation marker of osteoblasts in both MC3T3-E1 cells and non-osteogenic mouse pluripotent cell line,C3H10T1/2,indicating the action of CRE-SD was not cell-type specific.Alizarin red S activity showed a significant amount of calcium deposition in cells treated with CRE-SD.CRE-SD also upregulated the m RNA expression levels of transcription factors that favor osteoblast differentiation including Bmp-2,Runx2 and Collagen 1 a,in a dose dependent manner.Western blot analysis revealed that noggin attenuated CRE-SD-promoted expressions of Bmp-2 and Runx2 proteins.si RNA mediated blocking of Wnt/β-catenin signaling pathway also annulled the influence of CRE-SD,indicating Wnt/β-catenin dependent activity.Inhibition of the different signaling pathways abolished the influence of CRE-SD on ALP activity,confirming that CRE-SD induced MC3T3-E1 cells into osteoblasts through Wnt/β-catenin and BMP signaling pathway.Conclusion:These results collectively demonstrate that CRE-SD may be a potential therapeutic agent for the treatment of osteoporosis.