Maslinic acid suppresses osteoclastogenesis and prevents ovariectomy‐induced bone loss by regulating RANKL‐mediated NF‐κB and MAPK signaling pathways |
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Authors: | Zhenxi Li Yu Ma Lipeng Zhang Chunbing Zheng Wenwei Qiu Xian Wu Xiu Wang Hui Li Jie Tang Min Qian Dali Li Ping Wang Jian Luo Mingyao Liu |
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Affiliation: | 1. Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China;2. Institute of Medicinal Chemistry and Department of Chemistry, East China Normal University, Shanghai, China;3. Alkek Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA |
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Abstract: | Activation of NF‐κB and MAPK/activator protein 1 (AP‐1) signaling pathways by receptor activator NF‐κB ligand (RANKL) is essential for osteoclast activity. Targeting NF‐κB 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 dose‐dependent 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 IκBα phosphorylation and degradation, blocked NF‐κB/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‐κB and MAPK/AP‐1 signaling pathways and that MA is a promising agent in the treatment of osteoclast‐related diseases such as osteoporosis. © 2011 American Society for Bone and Mineral Research. |
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Keywords: | NF‐κ B NFATC1 MAPK OSTEOCLAST MASLINIC ACID |
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