Abstract: Objective · To investigate the crosstalk between receptor activator of nuclear factor-κB ligand (RANKL) / receptor activator of nuclear factorκB (RANK) system and Notch signaling pathways. Methods · Moosteoclast precursor cell line RAW264.7 was cultured and stimulatedRANKL (35 ng/L). Real-time PCR and Western blotting analysis were used to determine the s of Notch signaling molecules in RANKL-stimulated RAW264.7 cells. Small interfering RNA (siRNA) transfection was used to inhibit the of Notch1, Dll1 and Dll3 in Notch signaling pathways, then the mRNA and protein s of Rank were detected using real-time PCR and Western blotting analysis, respectively. Results · The s of Notch1, Jagged1 and Jagged2 were down-regulated while the of Dll4 was up-regulated after RANKL stimulation. The stimulation also inhibited the of Hes1 and Hey1. After siRNA transfection, the mRNA s of Notch1, Dll1 and Dll3 were suppressed71% (P0.000), 53% (P0.015) and 70% (P0.000), respectively. The mRNA and protein s of Rank were up-regulated after Notch1 inhibition (P0.003, P0.000). Conclusion · The data infers that the impact of Notch1 on RANKL/RANK system might play a key role in bone resorption conductedosteoclast.

Key words: osteoclast, bone resorption, Notch pathway, RANKL/RANK system