Notch signaling induces root resorption via RANKL and IL-6 from hPDL cells

Abstract

In this study, we first investigated the expressions of Jagged1, Notch2, the receptor activator of nuclear factor–kappa B ligand (RANKL), and interleukin (IL)-6 in areas of root resorption during experimental tooth movement in rats in vivo. We then assessed the effects of compression force (CF) with or without GSI (an inhibitor of Notch signaling) on Jagged1, RANKL, and IL-6 release from human periodontal ligament (hPDL) cells. Twelve male 6-wk-old Wistar rats were subjected to an orthodontic force of 50 g to induce mesially tipping movement of the upper first molars for 7 d. The expression levels of tartrate-resistant acid phosphatase, Jagged1, Notch2, IL-6, and RANKL proteins in the dental root were determined using an immunohistochemical analysis. Furthermore, the effects of the CF on Jagged1, IL-6, and RANKL production were investigated using hPDL cells in vitro. The effects of the cell-conditioned medium obtained from the hPDL cells subjected to CF (CFM) and Jagged 1 on osteoclastogenesis of human os...