Upregulation of mmu_circ_0001066 attenuates the inhibitory effect of bisphosphonates on osteoclastogenesis.

OBJECTIVE Medication-related osteonecrosis of the jaw (MRONJ) is the main adverse side effect of bisphosphonates (BPs), mainly owing to the inhibitory effect of BPs on osteoclastogenesis. CircRNAs were identified to be an important factor in regulating cellular processes. The aim of this study was to explore the effect of mmu_circ_0001066 on BP-inhibited osteoclastogenesis. MATERIALS AND METHODS The expression of MRONJ-related miRNA in RANKL-induced RAW264.7 cells treated with BP was analyzed using qRT-PCR analysis. Bioinformatics techniques were applied to screen potential circRNAs. Tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assays were used to examine the effect of mmu_circ_0001066 on osteoclastogenesis. Bioinformatics analysis, luciferase reporter assays, and Western blotting assays were performed to investigate the underlying mechanism. RESULTS Four MRONJ-related miRNAs were upregulated in BP-treated RAW264.7 cells and the expression of mmu_circ_0001066 was negatively correlated with those of MRONJ-related miRNAs. Furthermore, the upregulation of mmu_circ_0001066 partially attenuated the inhibitory effect of BP on osteoclastogenesis in RAW264.7 cells. Mechanistically, upregulated miR-16 suppressed osteoclastogenesis and miR-16 inhibitor increased osteoclastogenesis. Furthermore, we have identified that miR-16 is a downstream effector of mmu_circ_0001066. CONCLUSION Our results suggest that mmu_circ_0001066 played an important role in the BP-mediated suppression of osteoclastogenesis, which lays a foundation for identifying mmu_circ_0001066 as a potential biomarker for MRONJ.