Stauntonia hexaphylla (Lardizabalaceae) leaf methanol extract inhibits osteoclastogenesis and bone resorption activity via proteasome-mediated degradation of c-Fos protein and suppression of NFATc1 expression.
BACKGROUND
Natural plants, including common vegetables and fruits, have been recognized as essential sources for drug discovery and the development of new, safe, and economical medicaments. Stauntonia hexaphylla (Lardizabalaceae) is widely distributed in Korea, Japan, and China, and is a popular herbal supplement in Korean and Chinese folk medicine owing to its analgesic, sedative, and diuretic properties. However, the exact pharmacological effects of S. hexaphylla extract, particularly its effect on osteoclastogenesis, are not known.


METHODS
Osteoclast differentiation and function were identified with tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assay, and the underling mechanisms were determined by real-time RT-PCR and western blot analysis.


RESULTS
S. hexaphylla was found to inhibit early-stage receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation in bone marrow macrophages (BMMs) without cytotoxicity and bone-resorbing activity in mature osteoclasts in a dose-dependent manner. This S. hexaphylla-mediated blockade of osteoclastogenesis involved abrogation of the NF-κB, ERK, and c-Src-Btk-PLCγ2 calcium signal pathways. Interestingly, we found that S. hexaphylla down-regulated RANKL-associated c-Fos protein induction by suppressing its translation. Furthermore, ectopic overexpression of c-Fos and NFATc1 rescued the inhibition of osteoclast differentiation by S. hexaphylla. Furthermore, S. hexaphylla inhibited the c-Fos- and NFATc1-regulated expression of genes required for osteoclastogenesis, such as TRAP, OSCAR, β3-integrin, ATP6v0d2, and CtsK.


CONCLUSIONS
These findings suggest that S. hexaphylla might be useful for the development of new anti-osteoporosis agents.
Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.|Center for Metabolic Function Regulation, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.
Yoon-Hee
YH
Cheon
Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.
Jong Min
JM
Baek
Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.
Sun-Hyang
SH
Park
Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.
Sung-Jun
SJ
Ahn
Division of Rheumatology, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.|Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea.|Imaging Science based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, 570-749, Republic of Korea.
Myeung Su
MS
Lee
Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea. jmoh@wku.ac.kr.|Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk, 570-749, Republic of Korea. jmoh@wku.ac.kr.|Imaging Science based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, 570-749, Republic of Korea. jmoh@wku.ac.kr.
Jaemin
J
Oh
Imaging Science based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, 570-749, Republic of Korea. kimjy1014@gmail.com.
Ju-Young
JY
Kim
D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D001862:Bone Resorption / Q000378:metabolism / Q000517:prevention & control*; D002454:Cell Differentiation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects; D019684:Magnoliopsida; D008297:Male; D008813:Mice, Inbred ICR; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism*; D010010:Osteoclasts / Q000187:drug effects* / Q000502:physiology; D010024:Osteoporosis / Q000378:metabolism / Q000517:prevention & control; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects
D016328:NF-kappa B; D050778:NFATC Transcription Factors; C494005:Nfatc1 protein, mouse; D010936:Plant Extracts; D016760:Proto-Oncogene Proteins c-fos; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505689:Tnfsf11 protein, mouse; D046988:Proteasome Endopeptidase Complex