Maslinic acid suppresses osteoclastogenesis and prevents ovariectomy-induced bone loss by regulating RANKL-mediated NF-κB and MAPK signaling pathways

Abstract

Activation of NF-kB and MAPK/activator protein 1 (AP-1) signaling pathways by receptor activator NF-kB ligand (RANKL) is essential for osteoclast activity. Targeting NF-kB and MAPK/AP-1 signaling to modulate osteoclast activity has been a promising strategy for osteoclast-related diseases. In this study we examined the effects of maslinic acid (MA), a pentacyclic triterpene acid that is widely present in dietary plants, on RANKL-induced osteoclastogenesis, osteoclast function, and signaling pathways by in vitro and in vivo assay systems. In mouse bone marrow monocytes (BMMs) and RAW264.7 cells, MA inhibited RANKL-induced osteoclastogenesis in a dosedependent manner within nongrowth inhibitory concentration, and MA decreased osteoclastogenesis-related marker gene expression, including TRACP, MMP9, c-Src, CTR, and cathepsin K. Specifically, MA suppressed osteoclastogenesis and actin ring formation at early stage. In ovariectomized mice, administration of MA prevented ovariectomy-induced bone loss by inhibiting osteoclast activity. At molecular levels, MA abrogated the phosphorylation of MAPKs and AP-1 activity, inhibited the IkBa phosphorylation and degradation, blocked NF-kB/p65 phosphorylation, nuclear translocation, and DNA-binding activity by downregulating RANK expression and blocking RANK interaction with TRAF6. Together our data demonstrate that MA suppresses RANKL-induced osteoclastogenesis through NF-kB and MAPK/AP-1 signaling pathways and that MA is a promising agent in the treatment of osteoclast-related diseases such as osteoporosis. ß

Caffeic acid 3,4-dihydroxy-phenethyl ester suppresses receptor activator of NF-κB ligand–induced osteoclastogenesis and prevents ovariectomy-induced bone loss through inhibition of mitogen-activated protein kinase/activator protein 1 and Ca2+–nuclear factor of activated T-cells cytoplasmic 1 signaling pathways

“…(28) Briefly, BMMs were isolated from femurs and tibias of 4-week-old C57BL/6 mice and cultured in the presence of M-CSF (20 ng/mL) for 3 days. For differentiation into mature osteoclasts, osteoclast precursors were cultured with M-CSF (20 ng/mL) and RANKL (30 ng/mL) in 48-well culture plates for 7 days with media changed every 2 days.…”

“…For RAW264.7 cells, culture was performed as described. (28) 1 hour followed with 4,6-diamidino-2-phenylindole (DAPI) staining for 10 minutes. For pit assay, osteoclasts were cultured on FBS-coated dentin slices as described.…”

“…The second was a mouse osteoclast precursor cell line RAW264.7 with RANKL stimulation. (28) BMMs were incubated with various concentrations of CADPE during differentiation for 7 days, and RAW264.7 cells with CADPE for 3 to 5 days. As shown in Fig.…”

Caffeic Acid 3,4-Dihydroxy-Phenethyl Ester Induces Cancer Cell Senescence by Suppressing Twist Expression

“…A dual-luciferase assay was performed in triplicate as described previ- ously (Li et al, 2011). In brief, 2 ϫ 10 4 cells were placed on 24-well plates 24 h before transfection.…”

Crataegus pinnatifida: Chemical Constituents, Pharmacology, and Potential Applications

“…Additionally, maslinic acid could also regulate the downstream-signalling (MAPK); but it had no effects on calcium flow oscillation. Therefore, the results suggested maslinic acid might be used as a new drug against osteoporosis induced by menopause [103].…”