• The Journal of the Korean dental association
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• v.46 no.10
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• pp.623-632
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• 2008

Purpose : The purpose of this study is to identify the effect of zoledronate(Zometa(R)), which is most common nitrogen containing bisphosphonate, on survival, proliferation, and differentiation of osteoblast. Material & Methods: Twenty four cell culture plates containing essential medium were seeded with UMR-106 cell lines, at density of 5 x $10^4 cells per plates. Each plates were incubated with 5% $CO^2 incubator at $37^{\circ}C$. Starting from 2 days after incubation, cell culture medias were replaced, and added with osteogenesis induction media and 0, 0.01, 0.1, 0.5, 1, $3\muM$ of zoledronate(Zometa(R)), every 2 days, for 12 days. Control group was plates not added with zoledronate($0\muM$), and experiment group were plates added with different concentration of zoledronates(0, 0.01, 0.1, 0.5, 1, $3\muM$). Mature osteoblasts were identified with Alizarine Red staining, and protein samples were collected. Optical density was determined at wavelength of 405nm with ELISA reader. For viability analysis, cells were harvested and incubated with propidium iodide, and analysed with flow cytometry. Western blot technique was used to analyse Runx2 protein of osteoblast. Results : Secretion of bone matrix decreased as zoledronate concentration increased, and zoledronate did not effect survival rate of UMR-106 cells when measured with flow cytometer. Expression of Runx2 protein was inhibited as zoledronate concentration increased. Conclusion : From the results, we were able to identify that increase of zoledronate concentration inhibited differentiation of UMR-106 cell to osteoblast, without effecting quantity or survival rate.

• Biomolecules & Therapeutics
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• v.24 no.6
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• pp.589-594
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• 2016

Insulin is a peptide hormone of the endocrine pancreas and exerts a wide variety of physiological actions in insulin sensitive tissues, such as regulation of glucose homeostasis, cell growth, differentiation, learning and memory. However, the role of insulin in osteoblast cells remains to be fully characterized. In this study, we demonstrated that the insulin (100 nM) has the ability to stimulate the phosphorylation of protein kinase B (Akt/PKB) and extracellular signal-regulated kinase (ERK) and the levels of inhibin-${\beta}E$ in the osteoblast-like UMR-106 cells. This insulin-stimulated activities were abolished by the PI3K and MEK1 inhibitors LY294002 and PD98059, respectively. This is the first report proving that insulin is a potential candidate that enables the actions of inhibin-${\beta}E$ subunit of the TGF-${\beta}$ family. The current investigation provides a foundation for the realization of insulin as a potential stimulator in survival signaling pathways in osteoblast-like UMR-106 cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.79-79
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• 2003

Recently diabetes has been found to be associated with metabolic bone diseases such as osteoporosis. In the present study, attempts have been made-to explore the effect of high glucose in bone formation. Osteoblast-like UMR 106 cells were treated with high glucose (22mM, 33mM, 44mM) for 1 or 2 days. High glucose significantly inhibited proliferation of UMR106 cells in a time- and dose- dependent manner as evidenced by MTT assay. For the evaluation of collagen synthesis, UMR 106 cells were cultured in high glucose media (44mM) for 24 h and the ratio of collagen content to total protein was measured. In addition, gene expression pattern of type I collagen was assessed by RT-PCR. The high concentration of glucose inhibited a collagen synthesis, a marker of bone formation activity. JNK, c- Jun N-terminal Kinase, is known to play an important role in stress-associated cell death. In this regard, we tested to determine whether high glucose has any effect on JNK activity. It has been found that treatment of high glucose induced phosphorylation of JNK. On the other hand, ERK phosphorylation was inhibited by high glucose in a dose-dependent manner. Taken together, Therefore these results indicate that inhibition of proliferation in UMR 106 cells following high glucose is related to JNK/ERK containing signal pathways. This study showed high glucose concentration could alter the bone metabolism leading to defective bone formation, suggesting that high glucose due to diabetes may playa significant role in the development of metabolic bone disease.

• The Journal of the Korean dental association
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• v.46 no.9
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• pp.563-573
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• 2008

Purpose : The purpose of this study is to investigate the effects of Simvastain, which is HMG-CoA reductase inhibitor, on proliferation and differentiation of osteoblast. Materials & Methods : Twenty-four cell culture plates containing essential medium were seeded with UMR-106 cell lines, at density of 5 x $10^4$ cells per plate. Each plates were incubated with 5% $CO^2$incubator $37^{\circ}C$. Starting from 2 days after incubation, cell culture medias were replaced with Osteogenesis induction media every 2 days, for 12 days. In some plates, 0.01, 0.1, 1, 10, $100\muM$ of Simvastatin were added with Osteogenesis induction media, and classified as "test group". Those not added with Simvastatin were classified as "control group". Results : 1. When Alrizarin Red staining was observed with naked eye, control group showed normal deep red color, but test group show rapid decrease of red color as Simvastatin concentration increased more than $0.1\muM$. 2, When observed with microscope, compared to control group, amount of osteo matrix stained with Alrizarin Red decreased rapidly in Simvastatin concentration more than $0.1\muM$. 3. In optical density analysis, regarding control group as a basis, mineral deposition decreased rapidly when Simvastatin concentration increased more than $0.1\muM$. 4. In flow cytometry analysis, survival rate of UMR-106 cell showed no changes in both control group and test group. Conclusion : From the above results, we were able to identify that Simvastatin inhibited osteogenesis without effecting survival or cell number of osteoblasts.

• Biomolecules & Therapeutics
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• v.11 no.2
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• pp.81-84
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• 2003

Recently, diabetes has been found to be associated with osteoporosis. Specially in IDDM. In both type I and type II diabetes, glucose levels are elevated. Thus, a linkage between high glucose and osteoporosis can not be ruled out. In this study, an attempt has been made to observe the effect of high glucose on bone formation; osteoblast like UMR 106 cells were treated with high glucose (22 mM, 33 mM) for 1, 3 or 7 days. The high concentration of glucose inhibited markers. of bone formation activity such as alkaline phosphatase and collagen synthesis. In addition, reduction in the level of total cellular protein in response to high glucose was also observed. This study showed high glucose concentration could alter the bone metabolism leading to a defective bone formation and thus paving the linkage of such situation to diabetic complications.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.145-145
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• 1998

In the present study, we have demonstrated that taurine could stimulate the production of nitric oxide and the activity of ERK2 (extracellular signal regulated protein kinase or pp42 MAP kinase). Nitric oxide(NO), the product of inducible nitric oxide synthase(iNOS), is known to be implicated in the metabolism of bone. ERK cascade plays a key role in the gene expression of iNOS in osteoblastic cell. We investigated whether taurine (l-20mM) could stimulate ERK2 activity, nitric oxide production, and inducible nitric oxide synthase in osteoblast-like UMR-106 cells. Nitric oxide was measured spectophotometrically as nitrite and the activation of ERK2 and iNOS was studied using Western 145 blot analysis. Taurine increased the production of nitric oxide in a dose-dependent manner and the effect was reached to a maximum at 10 mM. The activation of iNOS were consistent with NO levels. The tyrosine phosphorylation of ERK2 was increased by taurine in a time-dependent manner. The these result suggest that taurine might stimulate the production of nitric oxide in osteoblast-like cells by the activation of ERK2 and could regulate the metabolism of bone via nitric oxide.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.119-123
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• 1999

Parathyroid hormone (PTH) treatment of bone and kidney-derived cells not only activates adenyly cyclase buy also increases intracellular free calcium, and translocates protein kinase C (PKC) from cytosol to plasma membranes. We have found that acute phorbol ester pretreatment significantly decreases PTH-induced calcium transients and the effect of phorbol ester was antagonized by staurosporine (ST). Although the major effect of ST in that study was the reversal of the action of phorbol ester, it appeared that ST may also have promoted the effect of PTH directly. To further investigate the observation, we examined the effect of ST on the intracellular calcium transients induced by PTH and $\alpha$-thrombin ($\alpha$-TH). For calcium transient experiments, UMR-106 cells were loaded with 2 mM fluo-acetoxymethylester for 30 min at room temperature. The cells were then washed and suspended in buffer containing 1 mM calcium. Fluorescence was detected at 530 nm, with excitation at 505 nm. ST alone did not cause calcium transients, but enhanced the transients elicited by PTH response. added 5 min before the hormone. Another protein kinase inhibitor H-7 likewise enhanced the calcium responses elicited by PTH, while genistein did not affect PTH response. Calcium transients elicited by $\alpha$-TH were also enhanced by ST. The results suggest that there might be tonically activated endogenous protein kinase(s) which inhibit calcium signaling of some calcemic agents.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.125.1-125.1
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• 2003

Diabetes is complex in nature but it gets further complicated in associating with number of other diseases like hypertension, ratinal disintegration, renal failure and many others. The latest addition to diabetic-complication is its association with bone degeneration disease:osteoporosis, which is a form of bone loss. In both the types of primary diabetes, the insulin dependent diabetes militus (IDDM) as well in insulin independent diabetes millitus (IIDM) the glucose metabolism is altered. (omitted)

• Biomolecules & Therapeutics
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• v.26 no.6
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• pp.584-590
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• 2018

Osteoporosis development is closely associated with oxidative stress and reactive oxygen species (ROS). Taurine has potential antioxidant effects, but its role in osteoblasts is not clearly understood. The aim of this study was to determine the protective effects and mechanisms of actions of taurine on hydrogen peroxide ($H_2O_2$)-induced oxidative stress in osteoblast cells. UMR-106 cells were treated with taurine prior to $H_2O_2$ exposure. After treatment, cell viability, apoptosis, intracellular ROS production, malondialdehyde content, and alkaline phosphate (ALP) activity were measured. We also investigated the protein levels of ${\beta}-catenin$, ERK, CHOP and NF-E2-related factor 2 (Nrf2) along with the mRNA levels of Nrf2 downstream antioxidants. The results showed that pretreatment of taurine could reverse the inhibition of cell viability and suppress the induced apoptosis in a dose-dependent manner: taurine significantly reduced $H_2O_2$-induced oxidative damage and expression of CHOP, while it induced protein expression of Nrf2 and ${\beta}-catenin$ and activated ERK phosphorylation. DKK1, a Wnt/${\beta}-catenin$ signaling inhibitor, significantly suppressed the taurine-induced Nrf2 signaling pathway and increased CHOP. Activation of ERK signaling mediated by taurine in the presence of $H_2O_2$ was significantly inhibited by DKK1. These data demonstrated that taurine protects osteoblast cells against oxidative damage via Wnt/${\beta}-catenin$-mediated activation of the ERK signaling pathway.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.101-101
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• 2001

In the present study, we explored to determine if insulin has any effect on the nuclear translocation of insulin receptor and tyrosine phosphoryaltion of nuclear proteins in the UMR-106 cells. Significant amount of insulin receptors and IRS-1 proteins were detected in the nucleus. IRS-1 and PI$_3$-Kinase appeared to translocate to the nucleus in a time dependent manner. Tyrosine phosphorylation of a number of proteins including 180 KDa, 85 KDa protein in the nucleus was significantly stimulated by insulin, suggesting IRS-1 and PI$_3$-Klnase was activated in the nucleus by insulin treatment. In addition, p70 S6 Kinase, a downstream target of PI3-Kinase was transiently appeared in the nucleus by insulin and its activity was stimulated by insulin. These results suggest that the insulin signaling system containing insulin receptor, IRS-1, PI$_3$-Kinase and p70 S6 Kinase operates in the nucleus of osteoblast cells. The nuclear insulin-mediated tyrosine phosphorylation may play an essential role in the gene expression, differentiation and growth of osteoblast cells.