Essential Roles of Bone Morphogenetic Protein-1 and Mammalian Tolloid-like 1 in Postnatal Root Dentin Formation Academic Article uri icon

abstract

  • INTRODUCTION: Mutations in the proteinase bone morphogenetic protein-1 (BMP1) were recently identified in patients with osteogenesis imperfecta, which can be associated with type 1 dentinogenesis imperfecta. BMP1 is co-expressed in various tissues and has overlapping activities with the closely related proteinase mammalian tolloid-like 1 (TLL1). In this study we investigated whether removing the overlapping activities of BMP1 and TLL1 affects the mineralization of tooth root dentin. METHODS: Floxed alleles of the BMP1 and TLL1 genes were excised via ubiquitously expressed Cre induced by tamoxifen treatment beginning at 3 days of age (harvested at 3 weeks of age) or beginning at 4 weeks of age (harvested at 8 weeks of age). Multiple techniques, including x-ray analysis, double-labeling with calcein and alizarin red stains for measurement of dentin formation rate, and histologic and immunostaining assays, were used to analyze the dentin phenotype. RESULTS: BMP1/TLL1 double knockout mice displayed short and thin root dentin, defects in dentin mineralization, and delayed tooth eruption. Molecular mechanism studies revealed accumulation of collagens in dentin and a sharp reduction in non-collagenous proteins such as dentin matrix protein 1 and dentin sialophosphoprotein. Furthermore, we found a strong reduction in tartrate-resistant acid phosphatase, which is likely caused by defects in bone cells. CONCLUSIONS: BMP1/TLL1 appear to play crucial roles in maintaining extracellular matrix homeostasis essential to root formation and dentin mineralization.

altmetric score

  • 0.25

author list (cited authors)

  • Wang, J., Muir, A. M., Ren, Y., Massoudi, D., Greenspan, D. S., & Feng, J. Q.

citation count

  • 11

publication date

  • November 2016