Formononetin attenuates osteoclastogenesis via suppressing the RANKL-induced activation of NF-κB, c-Fos, and nuclear factor of activated T-cells cytoplasmic 1 signaling pathway.
Formononetin (1), a plant-derived phytoestrogen, possesses bone protective properties. To address the potential therapeutic efficacy and mechanism of action of 1, we investigated its antiosteoclastogenic activity and its effect on nuclear factor-kappaB ligand (RANKL)-induced bone-marrow-derived macrophages (BMMs). Compound 1 markedly inhibited RANKL-induced osteoclast differentiation in the absence of cytotoxicity, by regulating the expression of osteoprotegerin (OPG) and RANKL in BMMs and in cocultured osteoblasts. Compound 1 significantly inhibited RANKL-induced tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and macrophage inflammatory protein-1α (MIP-1α) in a concentration-dependent manner. These effects were accompanied by a decrease in RANKL-induced activation of the NF-κB p65 subunit, degradation of inhibitor κBα (IκBα), induction of NF-κB, and phosphorylation of AKT, extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK). NF-κB siRNA suppressed AKT, ERK, JNK, and p38 MAPK phosphorylation. Furthermore, 1 significantly suppressed c-Fos and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), key transcription factors during osteoclastogenesis. SP600125, a specific inhibitor of JNK, reduced RANKL-induced expression of phospho-c-Jun, c-Fos, and NFATc1 and inhibited osteoclast formation. These results suggested that 1 acted as an antiresorption agent by blocking osteoclast activation.
Oriental Medicine Research Center for Bone and Joint Disease, East-West Bone & Joint Research Institute, Kyung Hee University , 149, Sangil-dong, Gangdong-gu, Seoul, Korea.
Jeong-Eun
JE
Huh
Wong In
WI
Lee
Jung Won
JW
Kang
Dongwoo
D
Nam
Do-Young
DY
Choi
Dong-Suk
DS
Park
Sang Hoon
SH
Lee
Jae-Dong
JD
Lee
D018932:Chemokine CCL2; D015850:Interleukin-6 / Q000378:metabolism; D007529:Isoflavones / Q000737:chemistry / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D015394:Molecular Structure; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects; D048789:Phytoestrogens / Q000737:chemistry / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects; D053245:RANK Ligand / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018932:Chemokine CCL2; D015850:Interleukin-6; D007529:Isoflavones; D016328:NF-kappa B; D048789:Phytoestrogens; D016760:Proto-Oncogene Proteins c-fos; D053245:RANK Ligand; C007768:formononetin; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases