RAC1 and periodontitis: During periodontitis progression, CD146/NG2 pericytes are enriched in the periodontal tissue region and can migrate to the alveolar bone surface and co-localize with ALP/OCN osteoblasts, and C-X-C motif chemokine ligand 12 (CXCL12) facilitates pericytes’ migration and increased differentiation towards osteoblasts through CXCL12-CXCR4-Rac1 signaling alveolar bone volume in periodontitis patients [58].