• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.67-73
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• 2015

The microcystin is a cyclic heptapeptide from metabolites of cyanobacteria in the genera mycrocystis, anabaeba as a result of eutrophication. It has been known that microcystin-LR is a potent inhibitor of the catalytic subunits of protein phosphatase-1 (PP-1) as well as powerful tumor promoter. The active site of microcystin actually has two metal ions $Fe^{2+}/Zn^{2+}$ close to the nucleophilic portion of PP-1-microcystin complex. We report the isolation and purification of this microcystin-LR from cyanobacteria (blue-green algae) obtained from Daechung Dam in Chung-cheong Do, Korea. Microcystin-LR was extracted from solid-phase extraction (SPE) sample preparation using a CN cartridge. The cyanobacteria extract was purified to obtain microcystin-LR by HPLC method and identified by LC/MS. The detail structural studies that can elucidate the possible role of monovalent and divalent metal ions in PP-1-microcystin complexation were carried out by utilizing molecular dynamics. Conformational changes in metal binding for ligands were monitored by molecular dynamic computation and potential of mean force (PMF) using the method of the free energy perturbation. The microcystin-metal binding PMF simulation results exhibit that microcystin can have very stable binding free energy of -10.95 kcal/mol by adopting the $Mg^{2+}$ ion at broad geometrical distribution of $0.5{\sim}4.5{\AA}$, and show that the $K^+$ ion can form a stable metal complex rather than other monovalent alkali metal ions.

• Molecules and Cells
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• v.38 no.7
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• pp.604-609
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• 2015

The active metabolite of vitamin D such as $1{\alpha}$,25-dihydroxyvitamin ($D_3(1{\alpha},25(OH)_2D_3)$ is a well-known key regulatory factor in bone metabolism. However, little is known about the potential of vitamin D as an odontogenic inducer in human dental pulp cells (HDPCs) in vitro. The purpose of this study was to evaluate the effect of vitamin $D_3$ metabolite, $1{\alpha},25(OH)_2D_3$, on odontoblastic differentiation in HDPCs. HDPCs extracted from maxillary supernumerary incisors and third molars were directly cultured with $1{\alpha},25(OH)_2D_3$ in the absence of differentiation-inducing factors. Treatment of HDPCs with $1{\alpha},25(OH)_2D_3$ at a concentration of 10 nM or 100 nM significantly upregulated the expression of dentin sialophosphoprotein (DSPP) and dentin matrix protein1 (DMP1), the odontogenesis-related genes. Also, $1{\alpha},25(OH)_2D_3$ enhanced the alkaline phosphatase (ALP) activity and mineralization in HDPCs. In addition, $1{\alpha},25(OH)_2D_3$ induced activation of extracellular signal-regulated kinases (ERKs), whereas the ERK inhibitor U0126 ameliorated the upregulation of DSPP and DMP1 and reduced the mineralization enhanced by $1{\alpha},25(OH)_2D_3$. These results demonstrated that $1{\alpha},25(OH)_2D_3$ promoted odontoblastic differentiation of HDPCs via modulating ERK activation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4393-4398
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• 2013

Background: Chromosomal translocations are genetic aberrations associated with specific non-Hodgkin lymphoma (NHL) subtypes. This study investigated the differential gene expression profile of Egyptian NHL cases based on a microarray approach. Materials and Methods: The study included tissue samples from 40 NHL patients and 20 normal lymph nodes used as controls. Total RNA was extracted and used for cDNA microarray assays. The quantitative real time polymerase chain reaction was used to identify the aberrantly expressed genes in cancer. Results: Significant associations of 8 up-regulated and 4 down-regulated genes with NHL were observed. Aberrant expression of a new group of genes not reported previously was apparent, including down-regulated NAG14 protein, 3 beta hydroxy-delta 5-c27 steroid oxi-reductase, oxi-glutarate dehydrogenase (lipo-amide), immunoglobulin lambda like polypeptide 3, protein kinase x linked, Hmt1, and caveolin 2 Tetra protein. The up-regulated genes were Rb binding protein 5, DKFZP586J1624 protein, protein kinase inhibitor gamma, zinc finger protein 3, choline ethanolamine phospho-transferase CEPT1, protein phosphatase, and histone deacetylase-3. Conclusions: This study revealed that new differentially expressed genes that may be markers for NHL patients and individuals who are at high risk for cancer development.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.488-494
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• 2015

A recent report showed that nuclear factor of activated T cell (NFATc) 1 is a member of the NFAT family and is strictly implicated osteoblast differentiation and bone formation. Furthermore, the precise expression and function of NFATc1 in periodontal tissue remains unclear. Therefore, the purpose of this study was to investigate the function of NFATc1 in osteoblastic differentiation, and the underlying mechanism regulating periodontal regeneration in human periodontal ligament cells (hPDLCs). NFATc1 messenger RNA (mRNA) and protein levels were accessed by reverse transcription-polymerase chain reaction (RT-PCR) and western blot assay, respectively. Cell proliferation determined using MTT assay. Differentiation was evaluated by alkaline phosphatase activity and formation of calcium nodule with alizarin red S staining. The mRNA expression of osteoblastic differentiation related genes were examined by RT-PCR. Marked upregulation of NFATc1 mRNA and protein was observed in cells grown in osteogenic medium (OS). NFATc1 transactivation was detected in hPDLCs that had been incubated in OS for 14 days. Treatment with $10{\mu}M$ cyclosporine A (CsA), a known calcineurin inhibitor, reduced the proliferation of hPDLCs, while $5{\mu}M$ CsA had no effect. Inhibition of the calcineurin/NFATc1 pathway by CsA, attenuated OS-induced osteoblastic differentiation in hPDLCs. In summary, this study demonstrates for the first time that NFATc1 plays a key role in osteoblastic differentiation of hPDLCs and activation of NFATc1 could provide a novel mechanism for periodontal bone regeneration.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.995-1005
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• 1999

Alveolar bone destruction is a character-istic of periodontal disease. Treponema denticola are found in significantly increased numbers in the sites affected with periodontal disease. In order to clarify the role of T. denticola in destruction of alveo-lar bone in periodontal disease, this study was undertaken to determine the effect of sonicated extract of T. denticola on osteo-clast differentiation in co-culture system of mouse bone marrow cells and calvaria cells. The ability of osteoclast formation was estimated by counting the number of tar-tartrate resistant acid phosphatase(TRAP) positive cells. Sonicated extract of this bacteria stimulated osteoclast formation in a dose dependent manner(p<0.05). Indomathacin, an inhibitor of prostaglandin synthesis, decreased osteoclast formation induced by sonicated extract of this bacte-bacteria(p<0.05). Extract-induced osteoclast formation was decreased, when sonicated extract of bacteria was heated(p<0.05). These findings suggest that T. denticola induces osteoclast differentiation, and protein component of this bacteria and $PGE_2$ may play an important role in this process.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.342-346
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• 2008

Aurintricarboxylic acid (ATA) prevents apoptosis in a wide range of cell types, including PC12 cells. ATA is known to increase the phosphorylation level of IGF-1 receptor (IGF-1R) and downstream signaling proteins. ATA can translocate across the plasma membrane of PC12 cells and inhibit protein tyrosine phosphatases (PTPs) and, therefore, it is not clear whether ATA exerted its antiapoptotic effect through activation of IGF-1R or by inhibition of cytosolic PTPs. When PC12 cells, deprived of serum, were treated with Fab fragment of anti-IGF-1R antibody to prevent the binding of ATA to the extracellular domain of IGF-1R, ATA was found to penetrate into the cytosolic space of the cells. Under these conditions, the survival-promoting effects of ATA were abolished, and the increase of phosphorylation and characteristic cleavage of IGF-1R were not observed. These results indicate that the antiapoptotic effect of ATA in PC12 cells is due to the binding of ATA to the extracellular domain of IGF-1R and subsequent activation of the IGF-1R, not inhibition of cytosolic PTP(s).

• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.400-403
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• 2012

A 10-year-old, intact male, toy poodle was presented with abdominal distension, truncal alopecia, hepatomegaly, and sustained elevation of alkaline phosphatase. Vacuolar hepatopathy and glycogen deposition in hepatocytes were confirmed by liver biopsy and ultrasound-guided fine-needle aspiration with periodic acid-Schiff (PAS) staining of mass lesion respectively. Cortisol and some sex hormones associated with adrenal gland were analyzed at IDEXX Reference Laboratories before and 1 hour after ACTH stimulation. The results of analysis confirmed elevation of some sex hormones including androstenedione, progesterone and 17 hydroxyprogesterone, not cortisol concentration, before and 1 hour after ACTH stimulation. The dog was diagnosed as atypical form of hyperadrenocorticism associated with sex steroids excess. The treatment was initiated with trilostane (0.5 mg/kg, PO, q12hr) that is an adrenal steroid synthesis inhibitor. Trilostane was administered for 8 weeks and the clinical sign including truncal alopecia was improved.

• Molecules and Cells
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• v.24 no.2
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• pp.224-231
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• 2007

$H_2O_2$, as an example of oxidative stress, induces cardiac myocyte apoptosis. Bcl-2 family proteins are key regulators of the apoptotic response while their functions can be regulated by post-translational modifications including phosphorylation, dimerization or proteolytic cleavage. In this study, we examined the role of various protein kinases in regulating total BAD protein levels in adult rat cardiac myocytes undergoing apoptosis. Stimulation with 0.1 mM $H_2O_2$, which induces apoptosis, resulted in a marked down-regulation of BAD protein, which is attributed to cleavage by caspases since it can be restored in the presence of a general caspase inhibitor. Inhibition of PKC, p38-MAPK, ERK1/2 and PI-3-K did not influence the reduced BAD protein levels observed after stimulation with $H_2O_2$. On the contrary, inhibition of PKA or specifically $PKC{\delta}$ resulted in up-regulation of BAD. Decreased caspase 3 activity was observed in $H_2O_2$ treated cells after inhibition of PKA or $PKC{\delta}$ whereas inhibition of PKA also resulted in improved cell survival. Furthermore, addition of okadaic acid to inhibit selected phosphatases resulted in enhanced BAD cleavage. These data suggest that, during oxidative stress-induced cardiac myocyte apoptosis, there is a caspase-dependent down-regulation of BAD protein, which seems to be regulated by coordinated action of PKA, $PKC{\delta}$ and phosphatases.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.463-472
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• 2020

Direct reprogramming, also known as a trans-differentiation, is a technique to allow mature cells to be converted into other types of cells without inducing a pluripotent stage. It has been suggested as a major strategy to acquire the desired type of cells in cell-based therapies to repair damaged tissues. Studies related to switching the fate of cells through epigenetic modification have been progressing and they can bypass safety issues raised by the virus-based transfection methods. In this study, a protocol was established to directly convert fully differentiated fibroblasts into diverse mesenchymal-lineage cells, such as osteoblasts, adipocytes, chondrocytes, and ectodermal cells, including neurons, by means of DNA demethylation, immediately followed by culturing in various differentiating media. First, 24 h exposure of 5-azacytidine (5-aza-CN), a well-characterized DNA methyl transferase inhibitor, to NIH-3T3 murine fibroblast cells induced the expression of stem-cell markers, that is, increasing cell plasticity. Next, 5-aza-CN treated fibroblasts were cultured in osteogenic, adipogenic, chondrogenic, and neurogenic media with or without bone morphogenetic protein 2 for a designated period. Differentiation of each desired type of cell was verified by quantitative reverse transcriptase-polymerase chain reaction/western blot assays for appropriate marker expression and by various staining methods, such as alkaline phosphatase/alizarin red S/oil red O/alcian blue. These proposed procedures allowed easier acquisition of the desired cells without any transgenic modification, using direct reprogramming technology, and thus may help make it more available in the clinical fields of regenerative medicine.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.68-76
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• 2004

Mistletoe lectin has been reported to induce apoptosis in different cancer cell lines in vitro and to show antitumor activity against a variety of tumors in animal models. We previously demonstrated the Korean mistletoe lectin (Viscum album var. coloratum, VCA)-induced apoptosis by down-regulation of Bcl-2 and telomerase activity and by up-regulation of Bax through p53- and p21-independent pathway in hepatoma cells. In the present study, we observed the induction of apoptotic cell death through activation of caspase-3 and the inhibition of telomerase activity through transcriptional down-regulation of hTERT in the VCA-treated A253 cells. We also observed the inhibition of telomerase activity and induction of apoptosis resulted from dephosphorylation of Akt in the survival signaling pathways. In addition, combining VCA with the inhibitors of phosphatidylinositol 3-kinase (PI3-kinase) upstream of Akt, wortmannin and LY294002 showed an additive inhibitory effect of telomerase activity. In contrast, the inhibitor of protein phosphatase 2A (PP2A), okadaic acid inhibited VCA-induced dephosphorylation of Akt and inhibition of telomerase activity. Taken together, VCA induces apoptotic cell death through Akt signaling pathway in correlated with the inhibition of telomerase activity and the activation of caspase-3. From these results, together with our previous studies, we suggest that VCA triggers molecular changes that resulting in the inhibition of cell growth and the induction of apoptotic cell death of cancer cells, which suggest that VCA may be useful as chemotherapeutic agent for cancer cells.