- Abstract -

Bone morphogenetic proteins (BMPs) are multi-functional growth factors that belong to the transforming growth factor beta (TGF beta) superfamily. The roles of BMPs in embryonic development and cellular functions in postnatal and adult animals have been extensively studied in recent years. Signal transduction studies have revealed that Smad1, 5 and 8 are the immediate downstream molecules of BMP receptors and play a central role in BMP signal transduction. Studies from transgenic and knockout mice and from animals and humans with naturally occurring mutations in BMPs and related genes have shown that BMP signaling plays critical roles in heart, neural and cartilage development. BMPs also play an important role in postnatal bone formation. BMP activities are regulated at different molecular levels. Tissue-specific knockout of a specific BMP ligand, a subtype of BMP receptors or a specific signaling molecule is required to further determine the specific role of a BMP ligand, receptor or signaling molecule in a particular tissue. This review article will focus on recent progress in identifying and characterizing BMP receptors, with emphasis on their possible roles in tooth development. Preclinical and clinical studies have shown that BMP-2 can be utilized in various therapeutic interventions such as bone defects, non-union fractures, spinal fusion, osteoporosis and root canal surgery. The mRNA expression patterns of several of the BMPs as well as the results from in vitro studies suggest that these proteins may be involved in regulating both tooth morphogenesis and differentiation of specialized cellular structures in the tooth. In the developing tooth, complex spatial and temporal expression patterns have been revealed for the receptors as well as the BMPs.

Key words: BMP, stem cells, dental tissues, odontoblasts, osteoblasts