Periodontal ligament stem cells (PDLSCs) play an important role in periodontal tissue regeneration and are expected to have future applications in cellular therapies for periodontitis. Porphyromonas gingivalis LPS inhibited the alkaline phosphatase activity, collagen type 1 Alpha 1, and osteocalcin production and mineralization in the PDLSCs which are positive for STRO-1 and SSEA-4. Porphyromonas gingivalis LPS also promoted cell proliferation and produced IL-1β, IL-6, and IL-8 [35]. Here, IL6 is linked to periodontitis.