Deacylcynaropicrin Inhibits RANKL-Induced Osteoclastogenesis by Inhibiting NF-κB and MAPK and Promoting M2 Polarization of Macrophages

Abstract

Inflammation can promote the maturity of osteoclasts and bone resorption in many bone disease such as osteoporosis and arthritis. Here, we aimed to investigate the inhibitory effects of deacylcynaropicrin (DAC) on osteoclastogenesis and bone resorption induced by RANKL. Bone-marrow-derived macrophages were used for assessing the influence of DAC on polarization of macrophages and osteoclastogenesis in vitro . Inducible nitric oxide synthase (iNOS) and CD206, as well as osteoclastogenesis markers, nuclear factor of activated T-cells 1 (NFATc1), and c-Fos, were qualitatively analyzed by immunofluorescence, flow cytometry, reverse transcription polymerase chain reaction, and Western blotting. The results showed that DAC significantly inhibited osteoclastogenesis by suppressing the expression levels of c-Fos and NFATc1 through nuclear factor-κB, c-Jun N-terminal kinase (JNK), and Akt pathway. Moreover, immunohistochemistry and enzyme-linked immunosorbent assays showed that DAC reduced the release of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 in vivo . Finally, DAC also promoted macrophage polarization from M1 to M2 types. In conclusion, these results demonstrated that DAC suppressed RANKL-induced inflammation and osteoclastogenesis and therefore it can be used as a potential treatment for osteoporosis, arthritis, osteolysis, and aseptic loosening of artificial prostheses.

Curcumin has immunomodulatory effects on RANKL‐stimulated osteoclastogenesis in vitro and titanium nanoparticle‐induced bone loss in vivo

“…8 Li et al reported that deacylcynaropicrin inhibited RANKL-mediated osteoclast fusion by promoting M2-type macrophage polarization. 24 A large number of studies have reported that M1-type macrophages were stimulated and induced by wear debris, which is generated from the surface of an implant prosthesis, and released proinflammatory cytokines, creating a proinflammatory microenvironment. 10,43,44 This proinflammatory microenvironment further activates the osteoclastic signalling pathways and promotes the recruitment and differentiation of osteoclast precursor cells.…”

“…8,24 Therefore, the immunomodulatory effects of curcumin on RAW264.7 cells were investigated using flow cytometry, ELISA, and immunofluorescence staining. 8,24 Therefore, the immunomodulatory effects of curcumin on RAW264.7 cells were investigated using flow cytometry, ELISA, and immunofluorescence staining.…”

“…Recent studies have demonstrated the immunomodulatory effect of macrophage polarization on the regulation of inflammation reactions, leading to alterations in wear debris-induced osteolysis and bone loss. 8,24 Therefore, the immunomodulatory effects of curcumin on RAW264.7 cells were investigated using flow cytometry, ELISA, and immunofluorescence staining. The results of flow cytometry (Figure 4) showed that the M1-type macrophages decreased from 66.06% in the TiPs group to 43.04% in the TiPs + Cur group, whereas the percentage of M2-type macrophages was higher in the TiPs + Cur group (40.63%) than in the TiPs group (17.89%) and control group (7.66%).…”

A selected small molecule prevents inflammatory osteolysis through restraining osteoclastogenesis by modulating PTEN activity

“…Many other related reports have noted that M1‐MΦ and M2‐MΦ participated in the inflammatory osteolysis 21,22 . In order to obtain M1‐MΦ, BMMs were stimulated with 50 ng/mL LPS or 20 ng/mL IFN‐γ for another 24 hours.…”

“…Many other related reports have noted that M1-MΦ and M2-MΦ participated in the inflammatory osteolysis. 21,22 In order to obtain M1-MΦ, BMMs were stimulated with 50 ng/mL LPS or 20 ng/mL IFN-γ for another 24 hours. Individually, to generate M2-MΦ, the BMM cells were incubated with 20 ng/mL IL-4 or 20 ng/mL IL-13 in the presence of 30 ng/mL M-CSF for 24 hours.…”