Expression of genes for bone morphogenetic proteins and receptors in human dental pulp

Bone morphogenetic proteins (BMP) have been shown to induce reparative dentine formation experimentally but the cells responsible, which respond to BMPs, have not been identified. The BMP signal is probably mediated by interaction of type I and II BMP receptors (R). Here, the RNA of human adult dental pulp and pulp cells in culture was examined by reverse transcription (RT) polymerase chain reaction (PCR) for evidence of mRNA for BMPs. mRNAs for BMP-2, -4, osteogenic protein-1, ActR-1 (activin-like kinase receptor), BMPR-IA, -IB and -II were detected by RT-PCR. The 698-bp PCR fragment for BMPR-IB was used to probe pulp cells for expression of that receptor. Cell expression of BMPR-IB was detected by the hybridization probe. The findings suggest that resident pulp cells may be able to respond to BMPs to initiate tissue formation.