Animals ; Apoptosis ; Cell Differentiation ; Cell Proliferation ; Fluoride Poisoning ; metabolism ; pathology ; Fluorosis, Dental ; metabolism ; pathology ; Hedgehog Proteins ; genetics ; metabolism ; Humans ; Osteoblasts ; cytology ; metabolism ; Osteoclasts ; cytology ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Signal Transduction ; Stomach Neoplasms ; metabolism ; pathology

We hypothesized that the formation and differentialtion of osteoclasts are accelerated and the potential of bone resorption is increased in the hemiplegic bone marrow in the early stage of stroke. We randomly divided white female Sprague-Dawley (SD) rats (n = 30) into two groups, stroke (n = 15) and sham group (n = 15). On the 7th day after stroke, after cutting away the epiphyses of the femurs and tibias, diaphyseal channels were flushed using alpha-minimum essential medium (alpha-MEM) and bone marrow cells were collected. Bone marrow stem cells, which were extracted from the femur and tibia, were cultured on the 7th day after middle cerebral artery occlusion. We then estimated the ratio of non-adherent cells to total bone marrow cells that included osteoclast precursor cells. After culturing these cells separately, cells that tested positive on the tartrate resistant acid phosphatase (TRAP) were counted and bone resorption was evaluated by using the OAAS(TM) plate. In comparison to the control group, the stroke group showed a higher increase of non-adherent cells in the hemiplegic side bone marrow. In addition, after the primary culture, the stroke group showed an increased number of TRAP positive cells and a higher degree of bone resorption estimated by OAAS(TM) plate. As a result, osteoclastogenesis and osteoclast differentiation are accelerated and the potential of bone resorption is increased in the hemiplegic bone marrow and these changes are detected as early as within the first week after middle cerebral artery occlusion in SD rats.
Animals ; Bone Marrow Cells/cytology/drug effects ; Bone Resorption/*physiopathology ; Cell Differentiation ; Cell Separation ; Cells, Cultured ; Female ; Femur/cytology ; Osteoclasts/cytology ; Rats ; Rats, Sprague-Dawley ; Stem Cells/cytology/metabolism ; Stroke/*metabolism/pathology ; Tartrates/pharmacology ; Tibia/cytology

Animals ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Cell Differentiation ; Humans ; Mouth Neoplasms ; metabolism ; pathology ; Oral Medicine ; Osteoblasts ; cytology ; Osteoclasts ; cytology ; Tooth ; metabolism ; Wnt Proteins ; metabolism ; physiology ; Wnt Signaling Pathway ; physiology ; beta Catenin ; metabolism

Adseverin is a Ca2+-dependent actin filament-severing protein that has been reported to regulate exocytosis via rearrangements of the actin cytoskeleton in secretory cells. However, the role of adseverin in bone cells has not yet been well characterized. Here, we investigated the role of adseverin in osteoclastogenesis using primary osteoclast precursor cells. Adseverin expression was upregulated during RANKL (receptor activator of nuclear factor-kappaB ligand)-induced osteoclast differentiation. Moreover, genetic silencing of adseverin decreased the number of osteoclasts generated by RANKL. Adseverin knockdown also suppressed the RANKL-mediated induction of nuclear factor of activated T-cell c1 (NFATc1), which is a key transcription factor in osteoclastogenesis. In addition, adseverin knockdown impaired bone resorption and the secretion of bone-degrading enzymes from osteoclasts. These effects were accompanied by decreased NFATc1 expression and the activation of nuclear factor-kappaB. Collectively, our results indicate that adseverin has a crucial role in osteoclastogenesis by regulating NFATc1.
Active Transport, Cell Nucleus ; Animals ; Bone Resorption/genetics/metabolism/pathology ; Cell Differentiation ; Cells, Cultured ; Female ; Gelsolin/genetics/*metabolism ; Gene Knockdown Techniques ; Humans ; Mice, Inbred ICR ; NF-kappa B/metabolism ; NFATC Transcription Factors/*metabolism ; Osteoclasts/*cytology/metabolism/pathology ; RANK Ligand/*metabolism

The OPG/RANKL/RANK system plays an important role in osteoclastogenesis and represents a great progress in bone biology. RANKL, which expresses on the surface of osteoblast/stromal cells and activated T cells, binds to RANK on the osteoclastic precursors or mature osteoclasts, and promotes osteoclastogenesis and bone resorption. While osteoprotegerin (OPG), which is expressed by osteoblasts/stromal cells, strongly inhibits bone resorption by binding to its ligand RANKL and thereby blocks the interaction between BANKL and RANK. A number of cytokines and hormones exert their effects on bone metabolism by regulating the OPG/RANKL ratio in the bone marrow microenvironment. RANK is also expressed on mammary epithelial cells and RANKL expression in these cells is induced by pregnancy hormones, RANKL and RANK are essential for the formation of the lactating mammary gland and the transmission of maternal calcium to neonates in mammalian species. Modulation of these systems provides a unique opportunity to develop novel therapeutics to inhibit bone loss in osteoporosis, rheumatoid arthritis, and bone metastasis of cancer. Further research should be focused on the cooperation of OPG/RANKL/RANK system with other signal pathways and the interactions among bone remodeling, immune system and endocrinology system. Currently, the development of OPG analogues or compounds which may stimulate OPG expression is becoming an attractive industry which may be profitable to both patients and manufacturers.
Animals ; Bone Resorption ; immunology ; metabolism ; Humans ; Osteoclasts ; cytology ; metabolism ; pathology ; Osteogenesis ; drug effects ; genetics ; immunology ; Osteoprotegerin ; metabolism ; physiology ; RANK Ligand ; metabolism ; physiology ; Receptor Activator of Nuclear Factor-kappa B ; metabolism ; pharmacology ; physiology ; T-Lymphocytes ; drug effects ; immunology

OBJECTIVETo investigate the effects of myeloma cells on the differentiation of osteoclast precursors (pOCs) into OCs in different culture systems in vitro and the interaction between OCs and myeloma cells.

METHODSMyeloma cell lines 8226, XG1 and XG7 and pOCs were cocultured in different culture system. OCs was examined by TRAP staining. RT-PCR was used to evaluate the expression of receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) of myeloma cells and the effects of myeloma cells on RANKL/OPG expression in coculture. The role of OCs in myeloma cells cycle was measured by FCM with PI staining. The supportive effects of OCs on myeloma cells survival were determined by FCM with double staining for annexin V and PI.

RESULTS8226 and XG1 cells could directly stimulate the differentiation of pOCs into TRAP+ multinuclear mature OCs. Myeloma cells, which expressed neither RANKL nor OPG, upregulated RANKL expression and decreased OPG expression in mouse primary bone marrow stromal cells (pBMSC). When OCs were co-cultured with myeloma cells, all OCs apparently remained alive after 7 days while devoid of sRANKL and M-CSF. OCs stimulated the proliferation of myeloma cells in co-culture systems,the cell number increased to (3.8 +/- 0.1) x 10(5)/well, (3.9 +/- 0.1) x 10(5)/well, (4.0 +/- 0.1) x 10(5)/well, and to (8.7 +/- 0.1) x 10(5)/well, (9.1 +/- 0.1) x 10(5)/well, (9.0 +/- 0.1 ) x 10(5)/well after co-culture for 3 days and 7 days for XG1 cells, XG7 cells and 8226 cells, respectively (P <0.01). However, OCs could counteract cytotoxic effects of dexamethasone. The proportion of Annexin V-/PI- cells were 57.71%, 82.18% and 90.92% for 8226 cells, XG1 and XG7 cells after co-culture with OCs (P <0.01).

CONCLUSIONMyeloma cells stimulated the differentiation of pOCs into TRAP+ multinuclear mature OCs by directly and/or indirectly disrupting the balance of RANKL/OPG, OCs promoted MM cells growth and survival, thus maintaining a vicious circle between myeloma cells and osteoclasts.

Animals ; Bone Marrow Cells ; metabolism ; Cell Communication ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; Coculture Techniques ; Humans ; Mice ; Multiple Myeloma ; pathology ; Osteoclasts ; cytology ; metabolism ; Osteoprotegerin ; metabolism ; RANK Ligand ; metabolism ; Stromal Cells ; metabolism

This study is to observe the effects of methopterin on the activation and bone resorption function of murine osteoclasts, which were obtained by induction from bone marrow cell and purified to the purity of 70%-80%. The mechanism underlying the inhibitory effects of methopterin on inflammatory bone destruction was explored. MTT method was used to determine the effect of methopterin on the proliferation of osteoclasts. Flow cytometric analysis was used to determine the effect of methopterin on the apoptosis of osteocalsts. TRAP stain, bone resorption lacuna stain and measurement of lacuna area were executed to determine the effects of methopterin on the activation and function of osteoclasts. ELISA method was used to determine the effect of methopterin on the MMP-9 secretion from osteoclasts. RT-PCR method was used to determine the effect of methopterin on the mRNA expression of RANK and MMP-9 in osteoclasts. The results showed that methopterin (0.1-10 micromol x L(-1)) inhibited the proliferation of osteoclasts, methopterin (0.1-10 micromol x L(-1)) could inhibit the activation and bone resorption function of osteoclasts and induced the apoptosis of osteoclasts. Methopterin (0.01-10 micromol x L(-1)) also decreased the mRNA expression of RANK, but only at 1-10 micromol x L(-1) decreased the mRNA expression of MMP-9. These results indicated that there were intense relation between the inhibitory effects on the activation and function of osteoclasts and the inhibition of inflammatory bone destruction by methopterin.
Animals ; Antirheumatic Agents ; pharmacology ; Apoptosis ; drug effects ; Bone Resorption ; pathology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Male ; Matrix Metalloproteinase 9 ; genetics ; metabolism ; Methotrexate ; pharmacology ; Mice ; Mice, Inbred C57BL ; Osteoclasts ; cytology ; metabolism ; RANK Ligand ; genetics ; metabolism ; RNA, Messenger ; metabolism

This study was aimed to investigate the role of bone marrow microenvironment in the regulation of activator protein 1 (AP-1) expression in multiple myeloma (MM) cells. The primary myeloma cells (CD138(+) cells) from 8 patients with MM were sorted by using immunomagnetic beads and were cocultured with osteoclasts in alpha-MEM supplemented with 10% fetal bovine serum, antibiotics, RNAKL (50 ng/ml) and macrophage colony-stimulating factor (25 ng/ml) for 10 to 14 days at 2.5 x 10(6) cells/ml. The expression levels of genes c-jun, junD fos and fosB were detected by real-time PCR. The results showed that the osteoclasts were observed after coculture of mononuclear cells in peripheral blood of MM patients with osteoclasts for 10 - 14 days. As compared with control (without coculture with osteoclasts), the viability of MM cells cocultured with osteoclasts obviously increased, the expression levels of c-jun, junD, fos and fosB decreased to 25.7% - 1.66%, 68.49% - 8.54%, 10.35% - 0.19% and 36.63% - 3.44% of the control respectively. It is concluded that the bone marrow microenvironment can inhibit the expression of c-jun, junD, fos and fosB promote myeloma cell proliferation and maintain cell survival.
Aged ; Bone Marrow ; metabolism ; pathology ; Coculture Techniques ; Female ; Gene Expression ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; Multiple Myeloma ; genetics ; metabolism ; pathology ; Osteoclasts ; cytology ; Transcription Factor AP-1 ; genetics ; Tumor Cells, Cultured

Osteoclast-like cells are known to inhibit arterial calcification. Receptor activator of NF-κB ligand (RANKL) is likely to act as an inducer of osteoclast-like cell differentiation. However, several studies have shown that RANKL promotes arterial calcification rather than inhibiting arterial calcification. The present study was conducted in order to investigate and elucidate this paradox. Firstly, RANKL was added into the media, and the monocyte precursor cells were cultured. Morphological observation and Tartrate resistant acid phosphatase (TRAP) staining were used to assess whether RANKL could induce the monocyte precursor cells to differentiate into osteoclast-like cells. During arterial calcification, in vivo and in vitro expression of RANKL and its inhibitor, osteoprotegerin (OPG), was detected by real-time PCR. The extent of osteoclast-like cell differentiation was also assessed. It was found RANKL could induce osteoclast-like cell differentiation. There was no in vivo or in vitro expression of osteoclast-like cells in the early stage of calcification. At that time, the ratio of RANKL to OPG was very low. In the late stage of calcification, a small amount of osteoclast-like cell expression coincided with a relatively high ratio of RANKL to OPG. According to the results, the ratio of RANKL to OPG was very low during most of the arterial calcification period. This made it possible for OPG to completely inhibit RANKL-induced osteoclast-like cell differentiation. This likely explains why RANKL had the ability to induce osteoclast-like cell differentiation but acted as a promoter of calcification instead.
Acid Phosphatase ; genetics ; metabolism ; Animals ; Aorta ; drug effects ; metabolism ; pathology ; Cell Differentiation ; Coculture Techniques ; Gene Expression Regulation ; Isoenzymes ; genetics ; metabolism ; Male ; Monocytes ; cytology ; drug effects ; metabolism ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; pathology ; Osteoclasts ; drug effects ; metabolism ; pathology ; Osteoprotegerin ; genetics ; metabolism ; RANK Ligand ; genetics ; metabolism ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Tartrate-Resistant Acid Phosphatase ; Vascular Calcification ; genetics ; metabolism ; pathology

OBJECTIVETo compare the effects of pamidronate and ibandronate on orthodontic root resorption.

METHODSSeventy-two 6-week-old female specific pathogen free (SPF) Wistar rats were selected to establish models for orthodontic tooth movement. The rats were randomly divided into three groups: the control group (C group), pamidronate group (Pm group) and ibandronate group (Ib group). 0.9% normal saline,0.5 mmol/L pamidronate and 0.5 mmol/L ibandronate were injected every 3 days. The rats were executed in batch on the 3rd, 7th and 14th day to make tissue sections. All statistical analysis was performed using the PASW Statistics 18 software package.

RESULTSOn the 7th and 14th day, the amount of cementoclast, the expression of osteoclast differentiation factor (ODF) and root resorption index were significantly lower in Pm group [the 7th day: (2.675 ± 0.002), (0.1683 ± 0.0007), (0.103 ± 0.003); the 14th day: (3.886 ± 0.048), (0.1873 ± 0.0014), (0.283 ± 0.001)] and Ib groups[the 7th day: (2.601 ± 0.001), (0.1634 ± 0.0010), (0.099 ± 0.002); the 14th day: (3.754 ± 0.019), (0.1818 ± 0.0016), (0.281 ± 0.001)] than in C group[the 7th day: (2.810 ± 0.001), (0.1792 ± 0.0008), (0.120 ± 0.001); the 14th day: (4.800 ± 0.001), (0.2060 ± 0.0007), (0.401 ± 0.001)] (P < 0.05). However, no significant difference was found between Pm and Ib groups on the 3rd, 7th and 14th day (P > 0.05).

CONCLUSIONSBoth pamidronate and ibandronate could inhibit orthodontic root resorption.

Animals ; Bone Density Conservation Agents ; pharmacology ; Cell Count ; Diphosphonates ; pharmacology ; Female ; Osteoclasts ; cytology ; drug effects ; metabolism ; RANK Ligand ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Root Resorption ; pathology ; prevention & control ; Tooth Movement Techniques