• BMB Reports
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• 제46권10호
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• pp.490-494
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• 2013

The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor-suppressing lipid phosphatase that is frequently absent in breast tumors. Thus, the stability of PTEN is essential for tumor prevention and therapy. The ubiquitin-proteasome pathway has an important role in regulating the functions of PTEN. Specifically, carboxyl terminus Hsp70-interacting protein (CHIP), the E3 ubiquitin ligase of PTEN, can regulate PTEN levels. In this study, we report that BCL-2-associated athanogene 5 (BAG5), a known inhibitor of CHIP activity, reduces the degradation of PTEN and maintains its levels via an ubiquitylation-dependent pathway. BAG5 is identified as an antagonist of cell tumorigenicity.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.289-298
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• 2005

Bone morphogenetic protein-7(BMP-7), a member of the transforming growth factor superfamily, stimulates osteoblast differentiation and bone formation. There are lots of evidences supporting a direct participation of periodontal ligament(PDL) cells on periodontal tissue regeneration. The purpose of this study was to evaluate the effect of recombinant human(rh) BMP-7 on primary rat PDL cells in vitro, with special focus on the ability of bone formation. The PDL cells were cultured with rhBMP-7 at the concentration of 0, 10, 25, 50, 100 and 200ng/ml for MTT assay. We evaluated the alkaline phosphatase activity at 3 and 5 days of incubation and the ability to produce mineralized nodules of rat PDL cells at 14 days of cell culture in concentration of 0, 10, 25, 50 and 100ng/ml. The cell activity was not reduced in cells treated with BMP-7 at $10{\sim}100ng/ml$, whereas the cell activity was reduced in the concentration of 200ng/ml than the control at day 1 and 3(p<0.01). At 3 and 5 day, alkaline phosphatase activity was significantly increased in cells treated with BMP-7 at 50ng/ml and 100ng/ml(p<0.05). The area of mineralized bone nodule was greater in cells treated with BMP-7 at 50 and 100 ng/ml than the control(p<0.01). These results suggest that rhBMP-7 stimulate rat PDL cells to differentiate toward osteoblast phenotype and secretion of the extracellular matrix of rat PDL cells.

• The Korean Journal of Physiology
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• 제30권2호
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• pp.209-218
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• 1996

Acetylcholine (ACh) activates the inwardly rectifying muscarinic $K^{+}$ channel in rat atrial cells via pertussis toxin (PTX)-sensitive G-protein ($G_k$) coupled with the muscarinic receptor (mAChR). Although this $K^{+}\;(K_{ACh})$ channel function has reported to be modulated by the phosphorylation process, a kinase and phosphatase involved in these processes are still unclear. Since either PKA or PKC was not effective on this ATP-modulation, the present study examined the possible involvement of the protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP) in the function of the $K_{ACh}$ Channel. In the inside-out (I/O) patch preparation excised from the adult rat atrial cell, when activated by 10 ${\mu}M$ ACh in the pipette and 100 ${\mu}M$ GTP in the bath, the mean open time (${\tau}_{o}$) and the channel activity ($K_{ACh}$) was 1.13 ms (n=5) and 0.19 (n=6), respectively. Following the application of 1 mM ATP into the bath, ${\tau}_{o}$ increased by 34% (1.54 ms, n=5) and $K_{ACh}$ by 66% (0.28, n=6). Channel function elevated by ATP was lasted after washout of ATP. However, this ATP-induced increase in the $K_{ACh}$ channel function did not occur in pretreated cells with genistein ($50{\sim}100 {\mu}M$), a selective PTK inhibitor, but occurred in pretreated cells with equimolar daidzein, a negative control of the genistein. On the contrary, PTP which acts on tyrosine residue conversely reversed both ATP-induced increased ${\tau}_{o}$ by 32% (1.20 ms, n=3) and $K_{ACh}$ by 41% (0.15, n=3), respectively. Taken together, these results suggest that $K_{ACh}$ channel may, at least partly, be regulated by the tyrosyl phosphorylation, although it is unclear where this process exerts on the muscarinic signal transduction pathway comprising the mAChR-$G_{k}$-the $K_{ACh}$ channel.

• The Korean Journal of Physiology and Pharmacology
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• 제17권5호
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• pp.447-453
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• 2013

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권1호
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• pp.7-13
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• 2017

In this study, changes in gene expression after administration of silk fibroin fragments ($size{\approx}30kDa$) were evaluated in MG63 cells using a cDNA microarray assay. In addition, the level of alkaline phosphatase (ALP) activity and cellular proliferation in the group administered moderately sized silk fibroin fragments ($size{\approx}30kDa$) (MSF) were compared to those in the group administered smaller silk fibroin fragments (size < 1 kDa) (SSF). The results of the cDNA microarray assay show increased expression of genes that are related to the cell cycle and inflammation. ALP, bone morphogenetic protein-7, bone morphogenetic protein receptor type IA, and runt-related transcription factor 2 exhibited significantly lower expression compared to control cells (fold ratio < 0.5). Relative ALP activity of the $100{\mu}g/mL$ MSF group was significantly lower than that of the SSF group (P < 0.05). Thus, the MSF group showed increased expression of genes associated with cellular proliferation and inflammation but decreased expression of genes associated with osteogenesis.

• BMB Reports
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• 제43권4호
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• pp.263-267
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• 2010

To characterize the biochemical properties of the PP2A regulatory B subunit, PPP2R5D, we analyzed its phosphorylation sites, stoichiometry and effect on holoenzyme activity. PPP2R5D was phosphorylated on Ser-53, Ser-68, Ser-81, and Ser-566 by protein kinase A, and mutations at all four of these sites abolished any significant phosphorylation in vitro. In HEK293 cells, however, the Ser-566 was the major phosphorylation site after PKA activation by forskolin, with marginal phosphorylation on Ser-81. Inhibitory tyrosine phosphorylation on Tyr-307 of the PP2A catalytic C subunit was decreased after forskolin treatment. Kinetic analysis showed that overall PP2A activity was increased with phosphorylation by PPP2R5D phosphorylation. The apparent Km was reduced from $11.25\;{\mu}M$ to $1.175\;{\mu}M$ with PPP2R5D phosphorylation, resulting in an increase in catalytic activity. These data suggest that PKA-mediated activation of PP2A is enabled by PPP2R5D phosphorylation, which modulates the affinity of the PP2A holoenzyme to its physiological substrates.

• Biomolecules & Therapeutics
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• 제23권2호
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• pp.141-148
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• 2015

Epithelial mesenchymal transition (EMT) is the first step in metastasis and implicated in the phenotype of cancer stem cells. Therefore, understanding and controlling EMT, are essential to the prevention and cure of metastasis. In the present study, we examined, by Western blot, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy, the effects of cardamonin (CDN) on transforming growth factor-${\beta}1$ (TGF-${\beta}1$)-induced EMT of A549 lung adenocarcinoma cell lines. TGF-${\beta}1$ induced expression of N-cadherin and decreased expression of E-cadherin. CDN suppressed N-cadherin expression and restored E-cadherin expression. Further, TGF-${\beta}1$ induced migration and invasion of A549 cancer cells, which was suppressed by CDN. TGF-${\beta}1$ induced c-Jun N-terminal kinase (JNK) activation during EMT, but CDN blocked it. Protein serine/threonine phosphatase 2A (PP2A) expression in A549 cancer cells was reduced by TGF-${\beta}1$ but CDN restored it. The overall data suggested that CDN suppresses TGF-${\beta}1$-induced EMT via PP2A restoration, making it a potential new drug candidate that controls metastasis.

• Journal of Trauma and Injury
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• 제26권3호
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• pp.81-88
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• 2013

Purpose: Among patients with multiple traumatic fractures, a tendency to form more callus exists in groups with multiple fractures combined with traumatic brain injury. This retrospective study evaluated the hematologic factors that might be useful to predict callus formation by comparing serologic tests and clinical and radiologic results in two groups. Methods: From January 2000 to December 2010, patients with femur shaft fractures were divided in two groups: one without traumatic brain injury (control group: 32 cases), and the other with traumatic brain injury (study group: 44 cases). We evaluated routine serologic exams and the amount of callus formation during the follow-up period. Results: Only the alkaline phosphatase level was statistically different between the two groups, not the White blood cell count, C-reactive protein, total calcium, and lactate dehydrogenase level. The amount of callus formation on the antero-posterior radiograph at the last follow up period was 74.9% in the study group and 42.1% in the control group. Then lateral radiograph showed 73.2% callus formation rate in the study group and 31.8% in the control group. Conclusion: In routine serologic exams, the two groups had no significant differences, except for the alkaline phosphatase level. The group with traumatic brain injury had much more callus formation, but there was no reliable factor to predict callus formation on the routine serologic exam.

• International Journal of Oral Biology
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• 제42권2호
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• pp.71-78
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• 2017

BMP-2 is a well-known TGF-beta related growth factor, having a significant role in bone and cartilage formation. It has been employed to promote bone formation in some clinical trials, and to differentiate mesenchymal stem cells into osteoblasts. However, it is difficult to obtain this protein in its soluble and active form. hBMP-2 is expressed as an inclusion body in the bacterial system. To continuously supply hBMP-2 for research, we optimized the refolding of recombinant hBMP-2 expressed in E. coli, and established an efficient method by using detergent and alkali. Using a heparin column, the recombinant hBMP-2 was purified with the correct refolding. Although combinatorial refolding remarkably enhanced the solubility of the inclusion body, a higher yield of active dimer form of hBMP-2 was obtained from one-step refolding with detergent. The refolded recombinant hBMP-2 induced alkaline phosphatase activity in mouse myoblasts, at $ED_{50}$ of 300-480ng/ml. Furthermore, the expressions of osteogenic markers were upregulated in hPDLSCs and hDPSCs. Therefore, using the process described in this study, the refolded hBMP-2 might be cost-effectively useful for various differentiation experiments in a laboratory.

• Molecular & Cellular Toxicology
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• 제5권3호
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• pp.222-229
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• 2009

Our previous finding that pre-initiation treatment of indole-3-carbinol (I3C) represents a chemopreventive effect in dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis has prompted us to test the global expression of genes at an early stage. Rats were continuously fed 300 ppm I3C in their diet at 6 weeks of age and were injected with DMBA at 7 weeks of age, and were sacrificed at 8 weeks of age. Global gene expression analysis using oligonucleotide microarrays was conducted to detect altered genes in DMBA- or DMBA plus I3C-treated mammary glands. Altered genes were identified by fold changes of 1.2 and by t-test (P<0.05) from the log ratios of the hybridization intensity of samples between control (Group 1) and DMBA (Group 2), and from those of samples between DMBA (Group 2) and DMBA plus I3C (Group 3). From these genes, we chose altered genes that were up- or down-regulated by DMBA treatment and recovered to the control level by I3C treatment. For early stage of carcinogenesis, I3C treatment induced the recovery to normal levels of several genes including cell cycle pathway (cyclin B2, cell division cycle 2 homolog A), MAP signaling pathway (fibroblast growth factor receptor 1, platelet derived growth factor receptor, beta polypeptide), and insulin signaling (protein phosphatase 1, regulatory (inhibitor) subunit 3B and flotillin 2), which were up-regulated by DMBA treatment. In addition, I3C treatment induced the recovery to normal levels of several genes including those of MAPK signaling (transforming growth factor, beta receptor 1 and protein phosphatase 3, catalytic subunit, beta isoform), which were down-regulated by DMBA treatment. These results suggest that the targeting of these genes presents a possible approach for chemoprevention in DMBA-induced mammary carcinogenesis.