Cyclolinopeptide F, a cyclic peptide from flaxseed inhibited RANKL-induced osteoclastogenesis via downergulation of RANK expression
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Previously, we reported that cyclolinopeptides (CLs) extracted from flaxseed inhibited receptor activator of nuclear factor κ-B ligand (RANKL)-induced osteoclastogenesis from mouse bone marrow cells in vitro. However, mode of action involved in CLs-inhibited osteoclastogenesis has been yet unknown. Therefore, in this study, we investigated the details of inhibitory activity of cyclolinopeptide-F (CL-F) in osteoclastogenesis, as a representative of CLs. CL-F dose-dependently inhibited RANKL-induced osteoclastogenesis (IC50 0.58 µM) without cytotoxic effects. The inhibition by CL-F was mainly observed in macrophage colony-stimulating factor (M-CSF)-induced proliferation/differentiation phase from M-CSF responsive immature myeloid cells to monocyte/macrophage (M/Mϕ) lineage. Additionally, CL-F also slightly inhibited RANKL-induced differentiation phase from M/Mϕ to mature osteoclasts. Expression of RANKL receptor, RANK, in M-CSF-induced M/Mϕ, i.e. osteoclast progenitor cells, was decreased by CL-F treatment. Furthermore, RT-PCR analysis revealed that CL-F inhibited c-fos gene expression, which is reported to be crucial for RANK expression in osteoclast progenitor cells induced with M-CSF from myeloid lineage cells. These results suggested that CL-F inhibits osteoclastogenesis via down regulation of c-fos expression, which leads to the down-regulation of RANK expression in M-CSF-induced osteoclast progenitors.
KeywordsFlaxseed Cyclic peptide Cyclolinopeptide Osteoclastogenesis Bone marrow macrophage Osteoclast
This work was partly supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
- 18.Kaneda T, Nojima T, Nakagawa M, Ogasawara A, Kaneko H, Sato T, Mano H, Kumegawa M, Hakeda Y (2000) Endogenous production of TGF-beta is essential for osteoclastogenesis induced by a combination of receptor activator of NF-kappa B ligand and macrophage-colony-stimulating factor. J Immunol 165:4254–4263CrossRefPubMedGoogle Scholar
- 19.Hayashi T, Kaneda T, Toyama Y, Kumegawa M, Hakeda Y (2002) Regulation of receptor activator of NF-kappa B ligand-induced osteoclastogenesis by endogenous interferon-beta (INF-beta) and suppressors of cytokine signaling (SOCS). The possible counteracting role of SOCSs-in IFN-beta-inhibited osteoclast formation. J Biol Chem 277:27880–27886CrossRefPubMedGoogle Scholar
- 23.Sato N, Sawada K, Kannonji M, Tarumi T, Sakai N, Ieko M, Sakurama S, Nakagawa S, Yasukouchi T, Krantz SB (1991) Purification of human marrow progenitor cells and demonstration of the direct action of macrophage colony-stimulating factor on colony-forming unit-macrophage. Blood 78:967–974PubMedGoogle Scholar