Secreted osteoclastogenic factor of activated T cells (SOFAT), a novel osteoclast activator, in chronic periodontitis

A novel activated human T cell-secreted cytokine, referred as secreted osteoclastogenic factor of activated T cells (SOFAT), that induce osteoclastogenesis in a RANKL-independent manner was recently described. This study evaluated the role of SOFAT in periodontal tissues and periodontitis. Gingival biopsies were harvested from systemically healthy non-periodontitis (n = 15) and chronic periodontitis patients (n = 15). The mRNA and protein levels of SOFAT were measured by qPCR and by enzyme-linked immunosorbent assay, respectively. Moreover, RAW 264.7 cells were cultured with SOFAT or Receptor activator of nuclear factor-kB ligand (RANKL) and stained for tartrate-resistant acid phosphatase (TRAP). Also, mice received a palatal injection between the first and second upper molar of SOFAT (100 ng/ml) or saline solution (0.9%). The upper jaw was removed, histologically processed and stained with hematoxilin and eosin to observe the presence of osteoclast-like cells. The mRNA and protein levels of SOFAT were significantly higher in the gingival tissue of the periodontitis group when compared to non-periodontitis one (p < 0.05). In addition, SOFAT potently induced TRAP-positive multinucleated cell formation by RAW 264.7 cells as well as induced the formation of osteoclast-like cells in the periodontal ligament in mice. The present study demonstrated that SOFAT may play an important role in periodontitis.