OBJECTIVETo examine the effects of brucine on the invasion, migration and bone resorption of receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis.

METHODSThe osteoclastogenesis model was builded by co-culturing human breast tumor MDA-MB-231 and mouse RAW264.7 macrophages cells. RANKL (50 ng/mL) and macrophage-colony stimulating factor (50 ng/mL) were added to this system, followed by treatment with brucine (0.02, 0.04 and 0.08 mmol/L), or 10 μmol/L zoledronic acid as positive control. The migration and bone resorption were measured by transwell assay and in vitro bone resorption assay. The protein expressions of Jagged1 and Notch1 were investigated by Western blot. The expressions of transforming growth factor-β1 (TGF-β1), nuclear factor-kappa B (NF-κB) and Hes1 were determined by enzyme-linked immunosorbent assay.

RESULTSCompared with the model group, brucine led to a dose-dependent decrease on migration of MDA-MB-231 cells, inhibited RANKL-induced osteoclastogenesis and bone resorption of RAW264.7 cells (P<0.01). Furthermore, brucine decreased the protein levels of Jagged1 and Notch1 in MDA-MB-231 cells and RAW264.7 cells co-cultured system as well as the expressions of TGF-β1, NF-κB and Hes1 (P<0.05 or P<0.01).

CONCLUSIONBrucine may inhibit osteoclastogenesis by suppressing Jagged1/Notch1 signaling pathways.

Animals ; Bone Neoplasms ; metabolism ; prevention & control ; secondary ; Breast Neoplasms ; drug therapy ; metabolism ; pathology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Female ; Humans ; Jagged-1 Protein ; metabolism ; Macrophages ; drug effects ; physiology ; Mice ; Osteoclasts ; drug effects ; physiology ; Receptor, Notch1 ; metabolism ; Signal Transduction ; drug effects ; Strychnine ; analogs & derivatives ; pharmacology ; therapeutic use

OBJECTIVETo study the mechanism underlying the inhibitory effect of Qingluo Tongbi Granule (, QTG) on osteoclast differentiation in rheumatoid arthritis in rats.

METHODSFibroblast and monocyte co-culture were used to induce osteoclast differentiation in adjuvant-induced arthritic (AIA) rats. Serum containing QTG was prepared and added to the osteoclasts, and activation of the tumor necrosis factor receptor-associated factor 6/mitogen-activated protein kinase/nuclear factor of activated T cells, cytoplasmic1 (TRAF6/MAPK/NFATc1) pathways was examined.

RESULTSThe induced osteoclasts were multinucleated and stained positive for tartrate-resistant acid phosphatase (TRAP) staining. Serum containing QTG at 14.4, 7.2 or 3.6 g/kg inhibited the activation of TRAF6, extracellular regulated protein kinase (ERK)1/2, c-Jun N-terminal kinase (JNK) and p38 and decreased the percentage of cells with nuclear NFATc1 in a dose-dependent manner, the high and middle doses exhibited clear inhibitory activity (P<0.01 and P<0.05, respectively). After the addition of MAPK inhibitors, the NFATc1 expression showed no significant difference compared with the control group (P>0.05).

CONCLUSIONSSerum containing QTG could generally inhibit the TRAF6/MAPK pathways and possibly inhibit the NFATc1 pathway. In addition, QTG may regulate other signaling pathways that are related to osteoclast differentiation and maturation.

Adjuvants, Immunologic ; adverse effects ; Animals ; Arthritis, Experimental ; pathology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Coculture Techniques ; Down-Regulation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Fibroblasts ; pathology ; Male ; Monocytes ; pathology ; Osteoclasts ; cytology ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Synovial Membrane ; pathology

Osteoarthritis is recognised to be an interactive pathological process involving the cartilage, subchondral bone and synovium. The signals from the synovium play an important role in cartilage metabolism, but little is known regarding the influence of the signalling from bone. Additionally, the collagenases and stromelysin-1 are involved in cartilage catabolism through mitogen-activated protein kinase (MAPK) signalling, but the role of the gelatinases has not been elucidated. Here, we studied the influence of osteoclastic signals on chondrocytes by characterising the expression of interleukin-1β (IL-1β)-induced gelatinases through MAPK signalling. We found that osteoclast-conditioned media attenuated the gelatinase activity in chondrocytes. However, IL-1β induced increased levels of gelatinase activity in the conditioned media group relative to the mono-cultured chondrocyte group. More specifically, IL-1β restored high levels of gelatinase activity in c-Jun N-terminal kinase inhibitor-pretreated chondrocytes in the conditioned media group and led to lower levels of gelatinase activity in extracellular signal-regulated kinase or p38 inhibitor-pretreated chondrocytes. Gene expression generally correlated with protein expression. Taken together, these results show for the first time that signals from osteoclasts can influence gelatinase activity in chondrocytes. Furthermore, these data show that IL-1β restores gelatinase activity through MAPK inhibitors; this information can help to increase the understanding of the gelatinase modulation in articular cartilage.
3T3 Cells ; Animals ; Cartilage, Articular ; cytology ; Cell Survival ; physiology ; Cells, Cultured ; Chondrocytes ; drug effects ; enzymology ; Coculture Techniques ; Culture Media, Conditioned ; Gelatinases ; drug effects ; Interleukin-1beta ; pharmacology ; JNK Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; MAP Kinase Signaling System ; physiology ; Matrix Metalloproteinase 2 ; drug effects ; Matrix Metalloproteinase 9 ; drug effects ; Mice ; Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; drug effects ; Monocytes ; cytology ; NF-kappa B ; antagonists & inhibitors ; Osteoclasts ; physiology ; Protease Inhibitors ; analysis ; Tissue Inhibitor of Metalloproteinase-1 ; drug effects ; Tissue Inhibitor of Metalloproteinase-2 ; drug effects ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors

OBJECTIVETo evaluate the influence of naringin on PMMA-induced osteoclastic bone resorption using the mouse air sacs model.

METHODSTotal 48 female Balb/c mices with the age of 8 to 10 weeks were chosen in the study. Air were injected into the back in 32 mices and formed the air sacs, 6 d later, the skulls (originated from other 16 mices) were implanted to the air sacs. Thirty-two animals were divided into naringin treatment group (with 2 concentrations of 150 mg/kg and 30 mg/ kg) , DMSO group and PBS blank group, 8 animals in each group. Polymethylmethacrylate (PMMA) particles were injected into the air sacs in naringin treatment groups and DMSO group so as to irritate inflammatory reaction. Naringin with 2 concentrations of 150 mg/kg and 30 mg/kg were dissolved in DMSO of 0.2 ml, and were injected into air sacs, respectively. In PBS black group, no stimulation with PMMA particles, only injected PBS, and in DMSO group, injected DMSO without naringin. Tartrate resistant acid phosphatase (TRAP), Ca2+ release, modified Masson stain and histological analysis were performed on the 7th day after stimulation.

RESULTSCompared with DMSO group, naringin treatment group's cellular infiltration decreased (P < 0.01); concentration of 150 mg/kg was better than that of concentrations of 30 mg/kg (8.90 ± 1.75 vs 15.23 ± 1.86). Naringin can decrease calcium release in the lavage of the air sacs bone resorption model, especially obvious in naringin with concentration of 150 mg/kg. Naringin can ameliorate the inflammatory reaction and the subsequent bone resorption (including bone collagen loss, TRAP positive cells amount and so on) in air sacs with bone implant and PMMA particles. Naringin with concentration of 150 mg/kg appeared to be an optimal dosage to deliver the therapeutic effects.

CONCLUSIONNaringin inhibits PMMA-induced osteoclastogenesis and ameliorates the PMMA-associated inflammatory reaction and the subsequent bone resorption.

Animals ; Disease Models, Animal ; Female ; Flavanones ; therapeutic use ; Mice ; Mice, Inbred BALB C ; Osteoclasts ; drug effects ; physiology ; Osteolysis ; chemically induced ; prevention & control ; Polymethyl Methacrylate ; toxicity

BACKGROUNDNeurofibromatosis type 1 (NF1) is the most common genetic syndrome predisposing patients to various tumors due to dysregulation of the Ras signaling pathway. Recent research has shown NF1 patients also suffer a spectrum of bone pathologies. The pathogenesis of NF1 bone diseases is largely unknown. There is no current treatment. By Nf1 heterozygote (Nf1+/-) mice and Nf1 conditional knockout mice, we and other groups demonstrated abnormal osteoblast and osteoclast function due to dysregulation of Ras signaling. However, the specific downstream effector pathways linked to NF1 abnormal osteoblastogenesis and osteoclastogenesis have not been defined. In this study, we investigated the Ras downstream effector related with NF1 bone disease.

METHODSWe used Nf1+/+ and Nf1+/- mice as normal and NF1 models. Bone stromal cells extracted from Nf1+/+ and Nf1+/- mice were induced osteoclasts. The osteoclast cell was stained by tartrate resistant acid phosphatase staining. The osteoclast cell number was counted and the surface area of osteoclast cells was calculated under the microscope. The mRNA of mammalian target of rapamycin (mTOR) was determined by quantitative reverse-transcription-polymerase chain reaction. The presence of ribosomal protein S6 kinase was determined by Western blotting.

RESULTSCompared with Nf1+/+ mice, Nf1+/- mice had about 20% more of osteoclast cells. These osteoclast cells were larger in size with more nuclei. Hyperactive mTOR was detected in Nf1+/- osteoclast cells. Inhibition of mTOR signaling by rapamycin in Nf1+/- osteoclasts abrogated abnormalities in cellular size and number.

CONCLUSIONmTOR pathway inhibition may represent a viable therapy for NF1 bone diseases.

Animals ; Male ; Mice ; Neurofibromatosis 1 ; drug therapy ; Osteoclasts ; drug effects ; physiology ; Osteogenesis ; drug effects ; Sirolimus ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; physiology

Platinum nanoparticles (PtNP) exhibit remarkable antioxidant activity. There is growing evidence concerning a positive relationship between oxidative stress and bone loss, suggesting that PtNP could protect against bone loss by modulating oxidative stress. Intragastric administration of PtNP reduced ovariectomy (OVX)-induced bone loss with a decreased level of activity and number of osteoclast (OC) in vivo. PtNP inhibited OC formation by impairing the receptor activator of nuclear factor-kappaB ligand (RANKL) signaling. This impairment was due to a decreased activation of nuclear factor-kappaB and a reduced level of nuclear factor in activated T-cells, cytoplasmic 1 (NFAT2). PtNP lowered RANKL-induced long lasting reactive oxygen species as well as intracellular concentrations of Ca2+ oscillation. Our data clearly highlight the potential of PtNP for the amelioration of bone loss after estrogen deficiency by attenuated OC formation.
Animals ; Metal Nanoparticles/*administration & dosage ; Mice ; Mice, Inbred C57BL ; NFATC Transcription Factors/metabolism ; *Osteoclasts/drug effects/physiology ; Osteoporosis/drug therapy ; Ovariectomy/adverse effects ; Oxidative Stress/drug effects ; Platinum/*administration & dosage ; *RANK Ligand/genetics/metabolism ; Reactive Oxygen Species/metabolism ; Signal Transduction

BACKGROUND/AIMS: The present study was performed to determine the effects of the ethyl acetate extract of Cudrania tricuspidata (EACT) on interleukin (IL)-1beta-stimulated receptor activator of NF-kappaB ligand (RANKL)-mediated osteoclast differentiation. METHODS: Bone marrow cells were harvested from 6-week-old male imprinting control region mice, and the differentiation of osteoclasts from these cells was evaluated by tartrate-resistant acid phosphatase and resorption pit formation assay. Phosphorylated extracellular signal regulated kinase (p-ERK), phosphorylated p38, phosphorylated c-Jun amino-terminal kinase, NF-kappaB (p65), IkappaBalpha, c-Fos, and nuclear factor of activated T-cells c1 (NFATc1) expression was examined by immunoblotting and quantitative reverse transcription-polymerase chain reaction. RESULTS: EACT inhibits IL-1beta-stimulated RANKL-mediated osteoclast differentiation. EACT also inhibits IL-1beta-stimulated RANKL-mediated phosphorylation of ERK 1/2, p38 mitogen activated protein kinase, and expression of c-Fos and NFATc1. CONCLUSIONS: These results suggest that EACT may be involved in the inhibition of bone loss by preventing osteoclast formation and may be used to manage bone destruction in inflammatory diseases, such as rheumatoid arthritis.
*Acetates ; Animals ; Bone Marrow Cells/cytology/drug effects/metabolism ; Cell Differentiation/drug effects/physiology ; Cell Survival/drug effects/physiology ; Cells, Cultured ; Down-Regulation/drug effects ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Interleukin-1beta/*pharmacology ; MAP Kinase Signaling System/*drug effects/physiology ; Male ; Mice ; Mice, Inbred ICR ; *Moraceae ; NFATC Transcription Factors/metabolism ; *Osteoclasts/cytology/drug effects/metabolism ; Plant Extracts/*pharmacology ; Proto-Oncogene Proteins c-fos/metabolism ; RANK Ligand/metabolism ; Stem Cells/cytology/drug effects/metabolism ; p38 Mitogen-Activated Protein Kinases/metabolism

This study was designed to investigate the effects of some Traditional Chinese Medicine (TCM) agents on bone resorption and morphometric features of osteoclasts as well as their relationships. TCM ShengGuZaiZaoSan and XianLingGuBao, were used to treat the experimental fracture. Thirty 6-month-old Chinchilla rabbits were used for the establishment of animal models each with a 3 mm bone defect in the middle of left radius as well as of right radius. These models were divided randomly into 3 groups : ShengGuZaiZaoSan Group (Group A), XianLingGuBao groups (Group B) and control-group (Group C). Every group was further divided into 2 subgroups: a former sacrificed group (14 days after operation) and a latter sacrificed group (31 days after operation). After the rabbits being killed, the samples of their undecalcified calli were subjected to the morphometry study of bone resorption and osteoclasts. Group A had more bone resorption, compared with Group B and C. Both Groups A and B exhibited some changed morphometric features of osteoclasts as compared with Group C (P < 0.05). Simple correlation analysis indicated that bone resorption is mainly correlated with osteoclast numbers, and that in individual group, bone resorption is correlated with osteoclast form factor, area and mean photodensity (P < 0.05). These allow us to conclude that ShengGuZaiZaoSan can increase bone resorption and accelerate bone remodeling by increasing osteoclast numbers at the former stage and can enhance osteoclast function at the latter stage. These changes are beneficial to fracture healing.
Animals ; Bone Remodeling ; drug effects ; Bone Resorption ; physiopathology ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Fracture Healing ; drug effects ; physiology ; Male ; Osteoclasts ; drug effects ; pathology ; Phytotherapy ; Rabbits ; Radius Fractures ; drug therapy ; pathology ; physiopathology ; Random Allocation

The recent identification of receptor activator of nuclear factor-kappaB ligand (RANKL)/RANK/osteoprotegerin (OPG) cytokine system has led to a new molecular perspective on osteoclast biology and bone homeostasis. Specifically, the interaction between RANKL and RANK is responsible for osteoclast differentiation. In the present study, we evaluated whether soluble RANK (sRANK) could act as an antagonist of RANKL and down-regulate osteoclastogenesis and bone resorption in vitro. The prokaryotic expression vector coding for sRANK was constructed. Then the construct was introduced into E. coli Origami B (DE3) competent cells and recombinant sRANK was successfully produced and purified through affinity chromatography. sRANK reduced osteoclast-like cell (OLC) formation and resorption pit formation induced by parathyroid hormone (PTH) in a dose-dependent manner. In addition, sRANK significantly inhibited PTH-induced mRNA expression of carbonic anhydrase II and tartrate-resistant acid phosphatase in murine bone marrow cells as confirmed by using semi-quantitative RT-PCR. The down-regulation was highly correlated with the effect of sRANK on OLC formation from marrow cells. These data demonstrate the anti-resorptive effects of sRANK in vitro and highlight the potential of sRANK as a novel therapeutic approach to bone disorders characterized by enhanced bone resorption.
Animals ; Bone Marrow Cells ; cytology ; Bone Resorption ; prevention & control ; Cell Differentiation ; drug effects ; Cells, Cultured ; Escherichia coli ; genetics ; metabolism ; Humans ; Mice ; Osteoclasts ; cytology ; Osteoprotegerin ; physiology ; Parathyroid Hormone ; antagonists & inhibitors ; physiology ; RANK Ligand ; physiology ; Receptor Activator of Nuclear Factor-kappa B ; biosynthesis ; genetics ; physiology ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology

OBJECTIVETo express human osteoprotegerin (OPG) in E. Coli and analyze its bioactivity in vitro.

METHODSSynthetic oligonucleotides were used to amplify human OPG gene by RT-PCR from total RNA of human osteosarcoma cell line MG63. The OPG cDNA coding for 380 amino acid residues was inserted into prokaryotic expression vector pRSET-A, transformed into competent E. Coli BL21, and induced by 0.1 mmol/l IPTG. SDS-PAGE and Western blot were performed to identify OPG-6His fusion protein. After purified by affinity chromatography, 1,000 microg/L or 1,500 microg/L of OPG-6His were added into the mouse bone marrow cells culture medium. The number of tartrate-resistant acid phophatase (TRAP)-positive multinucleated cells and resorption pits were counted to assess the bioactivity of expression products.

RESULTSThe sequence of OPG mature peptide encoding cDNA obtained in this experiment was as same as reported. SDS-PAGE showed 24% of total bacterial protein was of OPG-6His fusion protein. Western blot assay demonstrated that the molecular weight of recombinant protein was about 46 KD and could react specifically with human anti-OPG antibody. The mouse bone marrow cells were induced by 1alpha, 25-dihydroxyvitaminD3 (10(-8) mol/L) and Dexamethasone (10(-7) mol/L) to form osteoclastic-like multinucleated cells. 1,500 microg/L of purified OPG-6His protein could decrease the number of resorption pits and TRAP-positive multinucleated cells in vitro (P < 0.05), but it didn't show the same effects when the concentration of OPG-6His fusion protein was of 1,000 microg/L.

CONCLUSIONSHuman OPG-6His fusion protein is expressed and purified in E. Coli. The expression products have moderate inhibitory effects on osteoclast differentiation and bone resorption in vitro only when excessive amount of proteins are added into the culture medium, indicating that prokaryotic expression of fuctionalal OPG protein awaits further investigation.

Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cloning, Molecular ; Escherichia coli ; genetics ; Glycoproteins ; biosynthesis ; genetics ; Humans ; Osteoclasts ; drug effects ; physiology ; Osteoprotegerin ; Receptors, Cytoplasmic and Nuclear ; biosynthesis ; genetics ; Receptors, Tumor Necrosis Factor ; Recombinant Fusion Proteins ; biosynthesis ; pharmacology