Effect of BMP-2 and Emdogain on gene expression of PDSCs

Objectives: The application of periodontal stem cells (PDSCs) in the field of periodontal regeneration has emerged as a promising approach. Recently we introduced a new technique for the isolation and characterization of alveolar bone derived PDSCs. The aim of the present study was to evaluate the effect of Bone Morphogenetic Protein-2 (BMP-2) and Enamel Matrix Extract (Emdogain™) either solely or in combination on the gene expression profile and calcified nodules formation of PDSCs. Methods: PDSCs were isolated from human alveolar bone, magnetically sorted using STRO-1 antibodies and characterized by flow cytometric analysis of their surface marker expression, colony forming unit (CFU) ability and multilineage differentiation potential. Subsequently, PDSCs were treated over three weeks with either 100ng/ml BMP-2 (1st Group), or 100ìg/ml, Emdogain™ (Straumann, Freiburg, Germany) (2nd Group), or a combination of 100ng/ml BMP-2 and 100ìg/ml Emdogain™ (3rd Group). Unstimulated PDSCs (4th Group) as well as untreated osteoblasts (5th Group) served as controls. Gene expressions for Collagen-I, III, and V, Alkaline Phosphatase, Osteopontin, Osteocalcin, Osteonectin and Runx2 were analyzed using Reverse Transcriptase Quantitative Real Time Polymerase Chain Reaction (RTq-PCR) after 1, 2 and 3 weeks (N=3/group). Calcified nodule formation was investigated by Alizarin Red staining. Results: Compared to Groups 4 and 5, Group 1 showed significantly higher expression of Collagen-I, III, and V, Alkaline Phosphatase, and Osteonectin over the study time (p<0.05; Two-way ANOVA). Groups 2 and 3 showed the highest calcified nodule formation. Conclusion: BMP-2 appears to have the strongest effect on the gene expression profile of PDSCs, while the calcified nodule formation is greatly enhanced by the addition of Emdogain™ either solely or in combination with BMP-2.