Induced Odontogenic Differentiation of Mouse Bone Marrow Stromal Cells

Objectives: ES cells, which can be propagated indefinitely and differentiate into all cell lineages, are considered to be good resources of stem cells for tissue regeneration. However, the use of human ES cells has raised substantial ethical and technical issues. One way to obviate such critical issues is to obtain pluripotent stem cells directly from other sources of adult human. ES-like pluripotent cells have been identified in many adult tissues such as bone marrow, brain, amniotic fluid, skeletal muscle and adipose tissue. In the present study, we focused on bone marrow stromal cells and investigated their differentiaion ability into odontogenic lineage. Methods: MMSC-3 (a mouse bone marrow stromal cell line) was co-cultured with HAT-7 (a rat dental epithelial cell line). In brief, MMSC-3 was plated into 6-well culture plates. At confluence, the cell layer of MMSC-3 was coated with EMD® (enamel matrix derivative), matrigel® (basal lamina matrix), or GFR matrigel® (growth factor-reduced basal lamina matrix). After these extracellular matrices gelled, HAT-7 was plated onto the matrix and the cultures were maintained. Moreover, only MMSC-3 was cultured in the 6-well culture plates coated with EMD, matrigel® or GFR matrigel®. Odontogenic differentiation of MMSC-3 was investigated by RT-PCR for DSPP (dentin sialophosphoprotein), Msx-1 and Pax 9. Results: In the co-culture experiment, MMSC-3 expressed DSPP mRNA when cultured on any extracellular matrix tested. The highest level of the expression of DSPP was detected in the culture with matrigel® and HAT-7. In the monolayer culture, the expressin of DSPP was detected only when cultured on EMD and matrigel®. Conclusion: These findings suggest that bone marrow stromal cells had the ability to differentiate into odontogenic lineage and that this differentiation could be induced in vitro by some signals from dental epithelial cells and adequate extracellular matrices.