Functional analysis of core binding factor a1 and its relationship with related genes expressed by human periodontal ligament cells exposed to mechanical stress.

Mechanical stress induces human periodontal ligament (PDL) cells to express an osteoblastic phenotype in vitro. Core binding factor a1 (CBFA1) is a key regulator of osteoblast differentiation. This study was designed to investigate the role of CBFA1 in alveolar bone remodelling, specifically the expression of CBFA1 messenger RNA (mRNA) in human PDL cells under mechanical stress and its up- and downstream relationships with other bone remodelling markers. Cultured human PDL cells were exposed to mechanical stress. The expressions of CBFA1 and alkaline phosphatase (ALP), osteopontin (OPN), osteoprotegrin (OPG), and receptor activator nuclear factor kappa B ligand (RANKL) were detected before and after RNA interference (RNAi) of CBFA1. The data were analysed using a t-test and one-way analysis of variance. After mechanical stress loading, CBFA1 mRNA expression was raised initially, followed by an increased expression of ALP and RANKL, decreased expression of OPG, and a change in OPN expression. After CBFA1 knock-down in human PDL cells by small hairpin (sh) RNA, the expression of ALP, OPN, OPG, and RANKL also changed. These findings suggest that in the present model system CBFA1 may play an important role in PDL-mediated bone remodelling in response to mechanical stimulation. Mechanical stress: CBFA1-ALP and OPG-PDL homeostasis may be one of the signal transduction pathways of human PDL cell differentiation under mechanical stress without exclusion of the involvement of other pathways.