Pigment epithelium-derived factor modulates periodontal homeostasis in mice and induces osteogenic differentiation of human periodontal ligament fibroblasts

ABSTRACT

Aim

The aim of this study was to investigate the influence of pigment epithelium-derived factor (PEDF) on periodontal homeostasis in mice and the osteogenic differentiation of human periodontal ligament fibroblasts (PDLFs).

Materials and Methods

Micro-computed tomography and histology were performed to compare the alveolar bone volume, density, and bone-related markers between PEDF-deficient (PEDF^−/−) and wild-type (WT) mice. Furthermore, after recombinant human PEDF treatment, the PDLF viability and osteogenic differentiation were examined using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay, Von Kossa staining, Alizarin red staining, real-time quantitative polymerase chain reaction (qRT-PCR), and immunoblotting.

Results

The alveolar bone volume and density of PEDF^−/− mice were significantly lower than those of the WT mice. Higher receptor activator for nuclear factor-κB ligand (RANKL) expression and lower osteoprotegerin (OPG) expression levels were observed in the PEDF^−/− group. Moreover, PEDF treatment did not affect the PDLF proliferation. PEDF dose-dependently improved mineral deposition. Compared with the control group, 250 ng/mL PEDF promoted OPG mRNA expression in PDLFs on Day 3 but inhibited RANKL, Wnt5a, GSK3b mRNA, and non-phosphorylated β-catenin protein expression. However, 250 ng/mL PEDF had no significant effect on the expression of Wnt3a. On Day 7, after culture with 250 ng/mL PEDF in osteogenic medium, the ALP and RUNX2 protein levels were upregulated. VEGF protein expression was reduced in a dose-dependent manner after PEDF stimulation. The PEDF protein expression increased as the osteogenic induction time increased.

Conclusion

PEDF gene knockout suppresses periodontal homeostasis in mice, and PEDF treatment induces PDLF osteogenic differentiation in vitro.

KEYWORDS:

• Pigment epithelium-derived factor
• periodontal homeostasis
• periodontal ligament fibroblasts
• osteogenesis
• osteogenic differentiation

Acknowledgments

We appreciate all the participants who provide support for the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the National Natural Science Foundation of China (No. 81700957, No.81500838), the Natural Science Foundation of Guangdong Province under Grant Natural Science Foundation of Guangdong Province for Distinguished Young Scholars 2016a030310197 and the Young Teacher Training Program of Sun Yat-sen University under Grant 20ykpy76.