Notch1 Signaling During Osteogenic Differentiation of Mesenchymal Stem Cells

INTRODUCTION and OBJECTIVE: Notch signaling is an intercellular signaling pathway which contributes to the modulation of cell differentiation.This study was to examine the changes in Notch1 signaling during osteogenic differentiation of human mesenchymal stem cells (MSCs) derived from bone marrow.

MATERIALS and METHODS: Human bone marrow MSCs were cultured in DMEM (Dulbecco's Modified Eagle Medium).Osteogenic differentiation of MSCs was induced using osteogenic differentiation medium containing 100nM dexamethazone,10mM ß-glycerophosphate and 0.05mM ascorbic acid-2-phosphate in monolayer or three dimensional collagen-gel culture. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) level and calcium concentration in the culture medium and alizarin-red staining of the cultured cells. Gene expression levels of osteocalcin, ALP and type I collagen as bone markers, and Notch1 were examined by a quantitative real-time PCR analysis. Notch1 expression was also analyzed by immunohistochemical technique.

RESULTS: ALP level, alizarin-red staining and bone markers indicated the osteogenic differentiation of human bone marrow MSCs. The cells were also differentiated in the type I collagen gel. Notch1 level was enhanced during osteogenic differentiation.

CONCLUSION: The present study has suggested that Notch1 signaling may contribute to the osteogenic differentiation of human bone marrow MSCs.