Characterization of α-smooth muscle actin positive cells during multilineage differentiation of dental pulp stem cells


Correspondence: X. Cai, State Key Laboratory of Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu 610041, China. Tel.: +86-28-85503494; Fax: +86-28-85582167; E-mail:



Dental pulp tissue contains stem cells that can differentiate into multiple lineages under specific culture conditions; the origin of these dental pulp stem cells, however, is still unknown.

Materials and methods

Here we have utilized an α-SMA-GFP transgenic mouse model to characterize expression of a-smooth muscle actin (SMA)-GFP in subpassages of pulp-tissue-derived dental pulp cells, as perivascular cells express α-SMA.


During subculturing, percentages of cells expressing a-SMA increased signi?cantly from passage 1 to 3. α-SMA-GFP-positive cells expanded faster than α-SMA-GFP-negative cells. The dental pulp cells at passage 3 were induced towards osteogenic, adipogenic or chondrogenic differentiation. All three differentiated cell lines expressed high levels of α-SMA (mineralized nodules, lipid droplets and chondrocyte pellets). GFP expression colocalized with differentiated osteoblasts, adipocytes and chondrocytes. Co-culturing the α-SMA-GFP-positive cells with human endothelial cells promoted formation of tube-like structures and robust vascular networks, in 3-D culture.


Taken together, the a-SMA-GFP-positive cells were shown to have multilieange differentiation ability and to promote vascularization in a co-culture system with endothelial cells.