Inhibitory effects of PLAP-1/asporin on periodontal ligament cells

Plap-1/asporin is an extracellular matrix protein that is predominantly expressed in the human periodontal ligament (pdl) and has an aspartic acid (d) repeat polymorphism in its n-terminal region. in this study,we hypothesized that the d repeat polymorphism of plap-1/asporin may affect the physiological functions of periodontal ligaments. we established periodontal ligament cell lines transfected with the d13- or d14-plap-1 gene. alkaline phosphatase staining and alizarin red staining revealed that the cytodifferentiation of the d14-plap-1-expressing pdl cells was more repressed compared with that of the d13-plap-1-expressing cells. furthermore,the d14-plap-1-expressing cells inhibited bmp-2-induced cytodifferentiation more strongly than did the d13-plap-1-expressing cells. western blotting analysis and luciferase assay revealed that d14-plap-1 suppressed bmp-2 signal transduction more efficiently than did d13-plap-1,and co-immunoprecipitation demonstrated the stronger affinity of the d14-plap-1 protein to bmp-2 compared with the d13-plap-1 protein. analysis of these data suggests that the d repeat polymorphism of plap-1/asporin has a significant influence on the functions of pdl cells. © international & american associations for dental research.