The Role of Pericyte Migration and Osteogenesis in Periodontitis.

A ligature-induced periodontitis model was established in wild-type and CD146^CreERT2; Rosa^tdTomato mice to explore the function of pericytes in alveolar bone formation. We found that during periodontitis progression and periodontal wound healing, CD146⁺/NG2⁺ pericytes were enriched in the periodontal tissue areas, which could migrate to the alveolar bone surface and colocalize with ALP⁺/OCN⁺ osteoblasts. Chemokine C-X-C motif receptor 4 (CXCR4) inhibition using AMD3100 blocked CD146-Cre⁺ pericyte migration and osteogenesis, as well as further exacerbated periodontitis-associated bone loss. Next, primary pericytes were sorted out by magnetic-activated cell sorting and demonstrated that C-X-C motif chemokine ligand 12 (CXCL12) promotes pericyte migration and osteogenesis via CXCL12-CXCR4-Rac1 signaling. Finally, the local administration of an adeno-associated virus for Rac1 overexpression in NG2⁺ pericytes promotes osteoblast differentiation of pericytes and increases alveolar bone volume in periodontitis. Thus, our results provided the evidence that pericytes may migrate and osteogenesis via the CXCL12-CXCR4-Rac1 axis during the pathological process of periodontitis.