Kaempferol promotes proliferation and osteogenic differentiation of periodontal ligament stem cells via Wnt/β-catenin signaling pathway

Aims: Kaempferol, a type of flavonoid, is widely present in fruits, vegetables and medicinal herbs. This study was designed to investigate the effects of kaempferol on proliferation and osteogenesis of periodontal ligament stem cells (PDLSCs) and to identify the related pathway.

Materials and methods: PDLSCs were isolated from extracted premolars and cultured in vitro. Cell-counting kit-8 (CCK-8) and colony formation assays were performed to determine the effect of kaempferol, at various concentrations, on the proliferation of PDLSCs. Alkaline Phosphatase (ALP) activity was analyzed both quantitatively and qualitatively, and extracellular matrix mineralization was examined by alizarin red-S staining. In addition, the mRNA and protein expression levels of ALP, RUNX Family Transcription Factor 2 (RUNX2), Sp7 Transcription Factor (SP7; Osterix), Bone Gamma-Carboxyglutamate Protein (BGLAP; osteocalcin) and catenin beta 1 (CTNNB1; β-catenin) were monitored by qPCR and Western blot analysis. Additionally, the tankyrase inhibitor, XAV939, was used to determine the role of the Wnt/β-catenin pathway.

Key findings: The results illustrated that 10^-6 M kaempferol markedly promoted the proliferation, ALP activity and mineral deposition of PDLSCs (P < 0.05). The expression levels of ALP, RUNX2, SP7, BGLAP and β-catenin were all upregulated (P < 0.05). After blocking the Wnt/β-catenin pathway with XAV939, the effects of kaempferol were apparently reversed.

Significance: kaempferol enhanced proliferation and osteogenesis of PDLSCs by activating the Wnt/β-catenin signaling, which suggests the potential application of kaempferol for periodontal tissue regeneration.