Exopolysaccharide of Enterococcus faecium L15 promotes the osteogenic differentiation of human dental pulp stem cells via p38 MAPK pathway

Abstract

Background Bone has important functions in the body. Several researchers have reported that the polysaccharides and lipopolysaccharide derived from microbes can promote osteogenic differentiation of stem cells. Enterococcus faecium, a lactic acid bacterium (LAB), produces several bioactive metabolites and has been widely applied in the food and nutraceutical industries. The exopolysaccharide (EPS) from LAB has also been extensively examined for its postbiotic effects and for its in vivo and in vitro functionalities. However, studies on promoting bone differentiation using polysaccharides from LAB are lacking. Therefore, the purpose of this study was to investigate the effect of E. faecium L15 extract and EPS on osteogenic differentiation of human dental pulp stem cells (hDPSCs) and to identify the underlying mechanisms. Methods hDPSCs were obtained from dental pulp tissue, and L15 extract and EPS were isolated from L15. Gene and protein expression of the osteogenic differentiation markers were analyzed with qPCR and western blotting and the possible signaling pathways were also investigated using western blotting. Osteogenic differentiation potential was examined by alkaline phosphatase (ALP) staining and alizarin red s (ARS) staining. In addition, osteogenic differentiation potential of L15 EPS was explored in ex vivo culture of neonate murine calvaria. Results The calcium deposition and ALP activity were enhanced by addition of L15 extract or EPS. The expression levels of RUNX2, ALP, and COL1A1 mRNA and the protein expression levels of RUNX2, ALP, and BMP4 were increased in hDPSCs treated with the L15 extract or EPS. The L15 EPS treatment enhanced phosphorylation of the p38 mitogen-activated protein kinase (MAPK). The L15 EPS-induced increases in RUNX2, ALP, and BMP4 expression were suppressed by the p38 MAPK inhibitor SB203580. The promoting effect of L15 EPS on osteogenic differentiation was not only seen in hDPSCs, but also in osteoblast precursors. ALP activity and the expression of RUNX2, ALP, and COL1A1 increased in the L15 EPS-treated osteoblast precursors. In addition, L15 EPS increased bone thickness of neonate murine calvaria in ex vivo culture. Conclusions The stimulatory effect of L15 extract and EPS on osteogenic differentiation occurred through the p38 MAPK pathway, and L15 EPS enhanced new bone formation in neonate murine calvaria. These data suggest that L15 EPS has therapeutic potential applicable to bone regeneration.

Potential probiotic Lactobacillus delbrueckii subsp. lactis KUMS-Y33 suppresses adipogenesis and promotes osteogenesis in human adipose-derived mesenchymal stem cell

“…It has also been shown that L. rhamnosus GG rescues the proliferation and osteogenic differentiation of mandible‐derived mesenchymal stem cells (MMSCs) and thereby protects against mandibular bone loss (induced by tenofovir) in mice. The Kim et al study demonstrated that Enterococcus faecium L15 exopolysaccharide enhances the osteogenesis of human dental pulp stem cells through the p38 MAPK signaling pathway 76 .…”

TAZ reverses the inhibitory effects of LPS on the osteogenic differentiation of human periodontal ligament stem cells through the NF-κB signaling pathway

“…However, LPS at a concentration of 10 µg/ml significantly inhibited the osteogenic differentiation of hPDLSCs, which was in line with the findings of several previous studies [ 16 , 26 , 27 ]. Notably, the effects of LPS on cell osteogenic differentiation could differ based on the concentration of LPS because several previous studies reported that low concentrations of LPS (less than 1 µg/ml) had a positive effect on the osteogenesis of stem cells in vitro [ 24 , 25 , 28 – 30 ]. Considering that there may be a large amount of residual LPS in the periodontal tissues of patients with periodontitis, it is still necessary to protect hPDLSCs from the potential negative effects of LPS on osteogenic differentiation.…”

Resistin targets TAZ to promote osteogenic differentiation through PI3K/AKT/mTOR pathway

“…Firstly, although we identified that resistin targeted TAZ to induce OD through PI3K/AKT/mTOR pathway, the crosstalk with other signaling pathways cannot be ruled out, and the interaction between resistin and the OD-related genes remains to be further revealed. We next sought to explore other possible pathways, including Wnt/β-catenin pathway 42 , 43 and MAPK pathway, 44 , 45 and carry out relevant clinical studies. Secondly, bone defect remodeling is a dynamic process involving osteogenesis (bone formation) and osteoclastogenesis (bone resorption).…”