METHODS: SCAPs were isolated, cultured, and characterized. Cell viability was analyzed by Cell Counting Kit-8 assays (Dojindo, Kumamoto, Japan). Cell migration was investigated by transwell assays. Dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix were assessed by quantitative polymerase chain reaction and Western blots. Alkaline phosphatase (ALP) activity and ALP staining were assessed to determine the in vitro potential for osteogenic differentiation. The involvement of the Akt/Wnt/β-catenin signaling pathway was also studied.
RESULTS: In the 2.5-μg/mL LL-37 -treated group, cell proliferation and migration were up-regulated. Quantitative polymerase chain reaction and Western blot assays both revealed that LL-37 at 2.5 μg/mL up-regulated odonto/osteogenic markers (dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix). LL-37 at 2.5 μg/mL significantly promoted ALP activity and increased the staining in SCAPs. In addition, the p-Akt and p-glycogen synthase kinase-3β levels were increased in LL-37-treated SCAPs. The migratory and odonto/osteogenic differentiation capacities of SCAPs were inhibited after treatment with inhibitors LY294002 and XAV-939.
CONCLUSIONS: Our study showed that LL-37 at 2.5 μg/mL promoted the migration and odonto/osteogenic differentiation of SCAPs by activating the Akt/Wnt/β-catenin signaling pathway.