Immunohistochemical analysis of ALDH and CD44 in pulp stem cells

Stem cells from Human Exfoliated Deciduous teeth (SHED) and Dental Pulp Stem Cells (DPSC) were characterized as highly proliferative and clonogenic cells capable of differentiating into a variety of cells including neural cells and odontoblasts. Aldehyde Dehidrogenase (ALDH) and CD44 have been shown to be markers of stemness. Objective: To evaluate the expression levels of CD44 and ALDH in SHED and DPSC cells. Methods: Cells were cultured in Dulbecco's Modified Eagle Medium (DMEM) in a humidified incubator with 5% CO2 at 37oC.To investigate if ALDH and CD44 were present in SHED and DPSC we performed immunohistochemistry and immunofluorescence using monoclonal antibodies for CD44 (BD Bioscience) and ALDH (BD Bioscience). Results: Microscopic analysis demonstrated that SHED and DPSC stained positive for ALDH, and that this protein localized primarily in the cytoplasm. In addition, both cell types stained for CD44, which is mostly found in the cell membrane. Immunofluorescence confirmed that SHED and DPSC were strongly positive for ALDH and CD44. Conclusion: ALDH and CD44 are expressed by SHED and DPSC. This work suggests that CD44 and ALDH can be useful for the identification and characterization of dental pulp stem cells by immunohistochemistry.

Acknowledgments

This investigation was supported in part by grant 008/2006 from FAPESB, Bahia State Foundation for Research (to P.D.T.), and by the Dept. of Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry (to J.E.N.).