The use of TLR2 modified BMSCs for enhanced bone regeneration in the inflammatory micro-environment.

The repair of periodontal bone tissue defects in patients with periodontitis is one of the major challenges for dentists. Stem cell-based bone regeneration has been considered as a promising strategy to restore the lost periodontal bone tissue. However, the local inflammatory environment of periodontal tissue affects stem cell-based periodontal bone regeneration. Toll-like receptor 2 (TLR2), a member of the TLR family, plays an important role in regulating immunoreaction. Previous studies have shown that the activation of TLR2 signaling pathway is involved in enhancing tissue vascularization and wound healing. However, the mechanisms underlying the therapeutic effects of TLR2 on regulating bone marrow stromal cells (BMSCs) mediated periodontal bone tissue regeneration still need to be further investigated. In this study, we tested the effect of TLR2 on regulating BMSCs mediated alveolar bone regeneration by establishing a TLR2 gene-modified canine BMSCs using a lentivirus. Activation of TLR2 significantly enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and bone morphogenetic protein 2 (BMP-2) and then upregulated the expression of their downstream osteogenic and angiogenic related gene in BMSCs. TLR2-BMSCs mediated bone regeneration in canine tooth extraction sockets under an inflammatory environment demonstrated that activation of the TLR2 signaling pathway significantly stimulated BMSCs meditated angiogenesis and osteogenesis.