The Role of Autophagy on Osteogenesis of Dental Follicle Cells Under Inflammatory Microenvironment

This study investigated the role of autophagy on osteogenesis of DFCs under inflammatory microenvironment during tooth eruption.

DFCs were isolated and identified. Lipopolysaccharide (LPS) was used to construct the inflammatory microenvironment in vitro and in vivo. Cell viability was examined by CCK-8 assay. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining. The gene and protein levels were examined using qRT-PCR and western blot analysis, respectively. We observed the process of tooth eruption after local LPS injection by micro-CT and HE staining. Osteogenesis and autophagy were monitored through qRT-PCR, western blot and histological staining of specific markers.

LPS at the indicated concentrations did not produce toxic effects on DFCs, and significantly promoted the inflammatory gene expression. LPS inhibited osteogenic differentiation and activated autophagy in DFCs. Blocking autophagy with 3-MA reversed the expression of osteogenic markers in LPS-treated DFCs. Additionally, the eruption of LPS-treated teeth was accelerated and their DFs exhibited an increased expression of TNF-α and Beclin1, and decreased expression of ALP and RUNX2.

Autophagy was involved in the suppression of the DFCs osteogenesis in an LPS-induced inflammatory condition, suggesting the pivotal role of autophagy in inflammation-induced premature tooth eruption.