Osteoporosis is a bone pathology leading to increased fracture risk and challenging the quality of life. The aim of this study was to evaluate the effect of an anthraquinone glycoside, aloin, on osteogenic induction of MC3T3-E1 cells. Aloin increased alkaline phosphatase (ALP) activity, an early differentiation marker of osteoblasts. Aloin also increased the ALP activity in adult human adipose-derived stem cells (hADSC), indicating that the action of aloin was not cell-type specific. Alizarin red S staining revealed a significant amount of calcium deposition in cells treated with aloin. Aloin enhanced the expression of osteoblast differentiation genes, Bmp-2, Runx2 and collagen 1a, in a dose-dependent manner. Western blot analysis revealed that noggin and inhibitors of p38 MAPK and SAPK/JNK signals attenuated aloin-promoted expressions of Bmp-2 and Runx2 proteins. siRNA mediated blocking of Wnt-5a signaling pathway also annulled the influence of aloin, indicating Wnt-5a dependent activity. Inhibition of the different signal pathways abrogated the influence of aloin on ALP activity, confirming that aloin induced MC3T3-E1 cells into osteoblasts through MAPK mediated Wnt and Bmp signaling pathway.
Adult ; Alkaline Phosphatase ; Blotting, Western ; Calcium ; Collagen ; Core Binding Factor Alpha 1 Subunit ; Humans ; Osteoblasts ; Osteoporosis ; p38 Mitogen-Activated Protein Kinases ; Pathology ; Quality of Life ; RNA, Small Interfering ; Signal Transduction ; Stem Cells

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 mRNA expressions of osteoblast-specific genes and underline mechanisms were assessed by a real time PCR and western blot analysis. Results: CRE-SD 50 µg/mL 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 mRNA expression levels of transcription factors that favor osteoblast differentiation including Bmp-2, Runx2 and Collagen 1a, in a dose dependent manner. Western blot analysis revealed that noggin attenuated CRE-SD-promoted expressions of Bmp-2 and Runx2 proteins. siRNA 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.