Inhibition of Osteoclast Differentiation and Bone Resorption by Poria cocos Wolf Extract / 대한골다공증학회지

OBJECTIVES: Osteoclast differentiation and bone resorption are considered a potential therapeutic target to the treatment of erosive bone diseases, including osteoporosis and rheumatoid arthritis. Poria cocos Wolf (PCW), commonly used herbal medicine, has previously been reported to induce anti-inflammatory effect and anti-cancer effect, and to modulate immunologic responses. However, the effects of PCW on osteoclasts, and its detailed mechanisms are not proven. Therefore, we examined the inhibitory mechanism of PCW on osteoclast differentiation and bone resorption. MATERIALS AND METHODS: To analyze the effects of PCW on osteoclast differentiation, we examined osteoclast differentiation in bone marrow macrophages (BMMs) treated with or without of PCW by TRAP staining. The expression of c-Fos, NFATc1, TRAP and OSCAR mRNA was determined by RT-PCR and the protein levels of c-Fos, NFATc1, p38, ERK, JNK, Akt and IkappaB were assessed by western blot. Also, we evaluated the effect of PCW on bone resorption using hydroxyapatite plate. RESULTS: PCW significantly inhibited RANKL-mediated osteoclast differentiation without any evidence of cytotoxicity. We founded that PCW strongly inhibited RANKL-induced osteoclast formation when added during the early stage of cultures, suggesting that PCW acts on osteoclast precursors to inhibit RANKL/RANK signaling. Among the RANK signaling pathways, PCW inhibited the phosphorylation of p38 and JNK, also inhibited RANKL-induced expression of c-Fos, NFATc1, TRAP and OSCAR. In addition, PCW suppressed the bone resorption of mature osteoclasts. CONCLUSIONS: These findings suggest that PCW may be a potential novel drug for bone disorders by targeting the differentiation of osteoclasts as well as their functions.

Effect of Cornus Officinalis on Receptor Activator of Nuclear Factor-kappaB Ligand (RANKL)-induced Osteoclast Differentiation

OBJECTIVES: Osteoporosis is a disease of bones that is thought to result from an imbalance between bone resorption and bone formation. Although osteoporosis itself has no symptoms, osteoporosis caused by osteoclasts leads to an increased risk of fracture. Here we examined the effects of cornus officinalis on receptor activator of nuclear factor-kappaB ligand (RANKL)-mediated osteoclast differentiation. METHODS: We evaluated the effects of cornus officinalis on RANKL-induced osteoclast differentiation from bone marrow-derived macrophages (BMMs) and performed a cytotoxicity assay, reverse transcriptase-polymerase chain reaction (RT-PCR), and Western blot analysis. RESULTS: Cornus officinalis significantly inhibits RANKL-mediated osteoclast differentiation in a dose-dependent manner, but without cytotoxicity against BMMs. The mRNA expression of tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), c-Fos, and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) in BMMs treated with RANKL was considerably inhibited by cornus officinalis treatment. Also, cornus officinalis inhibits the protein expression of c-Fos and NFATc1. Cornus officinalis greatly inhibits RANKL-induced phosphorylation of p38 and c-JUN N-terminal kinase (JNK). Also, cornus officinalis significantly suppresses RANKL-induced degradation of I-kappaB. CONCLUSIONS: Taken together, our results suggest that cornus officinalis may be a useful the treatment of osteoporosis.

Inhibitory Effects of 1',2'-Dihydrorotenone on Osteoclast Differentiation and Bone Resorption In Vitro and In Vivo / 체질인류학회지

It is important to identify therapeutic compounds with no adverse effects for use in the chemotherapy of patients with bone-related diseases. The aim of this study was to identify a new compound that inhibits osteoclast differentiation and bone resorption. Herein, we examined the effects of 1',2'-dihydrorotenone on osteoclast differentiation and bone resorption in vitro and in vivo. 1',2'-dihydrorotenone inhibited receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast differentiation of cultured bone marrow macrophages (BMMs) in a dose-dependent manner. However, 1',2'-dihydrorotenone did not exert cytotoxic effect on BMMs. 1',2'-dihydrorotenone suppressed the expression of c-fos and NFATc1 as well as osteoclast-specific genes in BMMs treated with RANKL. Treatment with RANKL inhibited the expression of inhibitors of differentiation/DNA binding (Id)1, 2, and 3; however, in the presence of 1',2'-dihydrorotenone, RANKL did not suppress the expression of Id1, 2, and 3. Furthermore, 1',2'-dihydrorotenone inhibited bone resorption and considerably attenuated the erosion of trabecular bone induced by lipopolysaccharide treatment. Taken together, these results suggest that 1',2'-dihydrorotenone has the potential to be applied in therapies for bone-related diseases.

Amorphigenin inhibits Osteoclast differentiation by suppressing c-Fos and nuclear factor of activated T cells / 대한해부학회지

Among the several rotenoids, amorphigenin is isolated from the leaves of Amopha Fruticosa and it is known that has anti-proliferative effects and anti-cnacer effects in many cell types. The main aim of this study was to investigate the effects of amorphigenin on osteoclast differentiation in vitro and on LPS treated inflammatory bone loss model in vivo. We show here that amorphigenin inhibited RANKL-induced osteoclast differentiation from bone marrow macrophages in a dose dependent manner without cellular toxicity. Anti-osteoclastogenic properties of amorphigenin were based on a down-regulation of c-fos and NFATc1. Amorphigenin markedly inhibited RANKL-induced p38 and NF-kappaB pathways, but other pathways were not affected. Micro-CT analysis of the femurs showed that amorphigenin protected the LPS-induced bone loss. We concluded that amorphigenin can prevent inflammation-induced bone loss. Thus we expect that amorphigenin could be a treatment option for bone erosion caused by inflammation.

Effect of Water Extract of Papaya on RANKL-induced Osteoclast Differentiation / 대한해부학회지

Balance between bone-resorbing osteoclats and bone-forming osteoblasts is important in bone homeostasis. In particular, increased osteoclast formation and activity are responsible for bone diseases such as osteoporosis, rheumatoid arthritis, periodontal disease. Natural metabolites of plants have recently received much attention as lead compounds for the development of novel therapeutic strategy. The purpose of this study was to search the natural products to inhibition osteoclast differentiation. Water extract of papaya significantly inhibited receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclast differentiation in bone marrow macrophages (BMMs) in a dose dependent manner. However, water extract of papaya did not affect cytotoxicity when compared with control. Water extract of papaya inhibited the phosphorylation of p38 and JNK induced by RANKL. The mRNA expression of c-Fos, NFATcl, TRAP and OSCAR induced by RANKL was inhibited by water extract of papaya treatment. Also, water extract of papaya suppressed the protein expression of c-Fos and NFATc1 in BMMs treated with RANKL. Taken together, these results suggest that papaya may be a useful drug in the treatment of bone-related disease.

Roles of Sphingosine-1 Phosaphate During Pathogenesis of Bone Destruction and Inflammation in Rheumatoid Arthritis Mice Model / 대한해부학회지

Sphingosine 1-phosphate (S1P) is a bioactive lipid molecule that mediates cell proliferation, differentiation, migration, and angiogenesis in vivo. However, the roles of S1P on pathogenesis of arthritis have been not completely understood. This study was designed to determine the effects of S1P modulation on collageninduced arthritis (CIA) model. DBA/1J mice were injected with collagen into the tail for induction of CIA model. S1P was administered into the peritoneal cavity every other days from day 1 to day 42 after collagen injection. To determine the degree of damage in CIA, we examined macroscopic findings of CIA. The inflammation and bone destruction of CIA mice were evaluated by histo-patholigy and radiography (CT and microradiography). The expressions of TNF-alpha, IL-6, and RANKL which have important roles in pathogenesis of rheumatoid arthritis and bone destruction were observed by immuno-histochemical staining. After injection with collagen in the DBA/1J mice, CIA was induced by swelling in the knee and ankle joint. Administration of S1P suppressed damages and incidence of arthritis elicited by collagen. In histologic and radiographic studies, S1P strongly suppressed the infiltration of inflammatory cells, the swelling of synovial membrane, erosion, and the destruction of bone on CIA mice. Injection of S1P resulted in down-regulation of the expression of the pro-inflammatory and bone destruction mediators such as TNF-alpha, IL-6, and RANKL on CIA mice. Furthermore, S1P suppressed the differentiation of bone marrow cells into osteoclasts by RANKL. In conclusion, this study suggest that S1P has protective effects on inflammation and bone destruction during pathogenesis of CIA, which indicates S1P can be a new possible therapeutic strategy for rheumatoid arthritis

Tanshinone IIA inhibits osteoclast differentiation through down-regulation of c-Fos and NFATc1

Bone is a dynamic tissue that is regulated by the activity of bone-resorbing osteoclasts and bone-forming osteoblasts. Excessive osteoclast formation causes diseases such as osteoporosis and rheumatoid arthritis. Natural substances may be useful as therapeutic drugs to prevent many diseases in humans because they avoid the many side effects of treatment with chemical compounds. Here we show that tanshinone IIA isolated from Salvia miltiorrhiza Bunge inhibits the receptor activator of NF-kappaB ligand (RANKL)-mediated osteoclast differentiation of osteoclast precursors. Tanshinone IIA suppressed the expression levels of c-Fos and NFATc1 induced by RANKL. However, retrovirus-mediated overexpression of c-Fos induced the expression of NFATc1 despite the presence of tanshinone IIA and reversed the inhibitory effect of tanshinone IIA on osteoclast differentiation. Also, the introduction of osteoclast precursors with the NFATc1 retrovirus led to osteoclast differentiation in the presence of tanshinone IIA. Our results suggest that tanshinone IIA may have a role as a therapeutic drug in the treatment of bone disease such as osteoporosis.

Lipid rafts are important for the association of RANK and TRAF6

Rafts, cholesterol- and sphingolipid-rich membrane microdomains, have been shown to play an important role in immune cell activation. More recently rafts were implicated in the signal transduction by members of the TNF receptor (TNFR) family. In this study, we provide evidences that the raft microdomain has a crucial role in RANK (receptor activator of NF-kappaB) signaling. We found that the majority of the ectopically expressed RANK and substantial portion of endogenous TRAF2 and TRAF6 were detected in the low-density raft fractions. In addition, TRAF6 association with rafts was increased by RANKL stimulation. The disruption of rafts blocked the TRAF6 translocation by RANK ligand and impeded the interaction between RANK and TRAF6. Our observations demonstrate that proper RANK signaling requires the function of raft membrane microdomains.