Alisol-B, a novel phyto-steroid, suppresses the RANKL-induced osteoclast formation and prevents bone loss in mice.
Osteoclasts, bone-resorbing multinucleated cells, are differentiated from hemopoietic progenitors of the monocyte/macrophage lineage. Bone resorption by osteoclasts is considered a potential therapeutic target to the treatment of erosive bone diseases, including osteoporosis, rheumatoid arthritis, and periodontitis. In the present study, we found that alisol-B, a phyto-steroid from Alisma orientale Juzepczuk, exhibited inhibitory effects on osteoclastogenesis both in vitro and in vivo. Although RT-PCR analysis showed that alisol-B did not affect the 1alpha,25(OH)(2)D(3)-induced expressions of RANKL, OPG and M-CSF mRNAs in osteoblasts, addition of alisol-B to co-cultures of mouse bone marrow cells and primary osteoblasts with 10(-8)M 1alpha,25(OH)(2)D(3) caused significant inhibition of osteoclastogenesis. We further examined the direct effects of alisol-B on osteoclast precursors. Alisol-B strongly inhibited RANKL-induced osteoclast formation when added during the early stage of cultures, suggesting that alisol-B acts on osteoclast precursors to inhibit RANKL/RANK signaling. Among the RANK signaling pathways, alisol-B inhibited the phosphorylation of JNK, which are upregulated in response to RANKL in bone marrow macrophages, alisol-B also inhibited RANKL-induced expression of NFATc1 and c-Fos, which are key transcription factors for osteoclastogenesis. In addition, alisol-B suppressed the pit-forming activity and disrupted the actin ring formation of mature osteoclasts. In a hypercalcemic mouse model induced by 2-methylene-19-nor-(20S)-1alpha,25(OH)(2)D(3) (2MD), an analog of 1alpha,25(OH)(2)D(3), administration of alisol-B significantly suppressed 2MD-induced hypercalcemia as resulting from the inhibition of osteoclastogenesis. Taken together, these findings suggest that alisol-B may be a potential novel therapeutic molecule for bone disorders by targeting the differentiation of osteoclasts as well as their functions.
Lee
Ji-Won
JW
Institute for Oral Science, Matsumoto Dental University, Shiojiri, Nagano, Japan. jwlee@isc.chubu.ac.jp
Kobayashi
Yasuhiro
Y
Nakamichi
Yuko
Y
Udagawa
Nobuyuki
N
Takahashi
Naoyuki
N
Im
Nam-Kyung
NK
Seo
Hwa-Jeong
HJ
Jeon
Won Bae
WB
Yonezawa
Takayuki
T
Cha
Byung-Yoon
BY
Woo
Je-Tae
JT
D000818:Animals; D001862:Bone Resorption / Q000473:pathology / Q000517:prevention & control*; D002783:Cholestenones / Q000494:pharmacology* / Q000627:therapeutic use; D018920:Coculture Techniques; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects* / Q000502:physiology; D053245:RANK Ligand / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D013256:Steroids / Q000494:pharmacology / Q000627:therapeutic use
D002783:Cholestenones; D053245:RANK Ligand; D013256:Steroids; C457232:alisol B