• Journal of Life Science
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• v.25 no.5
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• pp.585-593
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• 2015

Stress fiber (SF) alteration is mediated by cellular receptors, which, upon interaction with the extracellular counterpart, signal to the actin cytoskeleton for remodeling. This association is mediated by a variety of scaffold and signaling factors, which control the mechanical and signaling activities of the interaction site. The heterotrimeric transmembrane lymphotoxin α1β2 (LTα1β2), a member of the tumor necrosis factor (TNF) family of cytokines, including soluble homotrimeric lymphotoxin (LT α), plays an important role in lymphoid tissue architecture. Ligation between LTα1β2 and the lymphotoxin β receptor (LTβR) activates signal-cascade in fibroblastic reticular cells (FRCs). We found LTβR stimulation using an agonistic anti-LTβR antibody alone or combined with LTα or TNFα induced changes in the actin and plasticity of cells. To clarify the involvement of myosin underlying the alteration, we analyzed the effect of myosin light chain kinase (MLCK) with an MLCK inhibitor (ML7), the phosphorylation level of myosin light chains (MLC), and the level of phospho-myosin phosphatase target subunit 1 (MYPT1) after treatment with an agonistic anti-LTβR antibody for cytoskeleton reorganization in FRCs. The inhibition of MLCK activity induced changes in the actin cytoskeleton organization and cell morphology in FRC. In addition, we showed the phosphorylation of MLC and MYPT1 was reduced by LTβR stimulation in cells. A DNA chip revealed the LTβR stimulation of FRC down-regulated transcripts of myosin and actin components. Collectively, these results suggest LTβR stimulation is linked to myosin regarding SF alteration in FRC.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.505-509
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• 2002

In the course of screening program for VHR DS-PTPase (dual-specificity protein tyrosine phosphatase) from natural sources, Gastrodia elata was selected. One compound showing potent inhibitory activity was isolated by the solvent extraction and column chromatography including silica gel, ODS RP-18, Sephades LH-20, and HPLC. This compound was identified as baicalein by several NMR techniques such as $^1H-NMR$, $^{13}C-NMR$, and DEPT. Baicalein showed selective inhibitory activity against VHR DS-PTPase with $IC_{50}=2.4\;{\mu}M$, and showed cytotoxicity against several human cancer cell lines with an $GI_{50}$ of $5.26{\sim}12.93\;{\mu}g/mL$ range, including, melanoma (LOX-IMVI), lung cancer (NCI H23 and A549), colon cancer (HCT 116 and SW 620), prostate cancer (PC-3), and leukemia (MOLT 4F).

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.4
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• pp.417-426
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• 2023

The TRPM4 gene encodes a Ca²⁺-activated monovalent cation channel called transient receptor potential melastatin 4 (TRPM4) that is expressed in various tissues. Dysregulation or abnormal expression of TRPM4 has been linked to a range of diseases. We introduced the hemagglutinin (HA) tag into the extracellular S6 loop of TRPM4, resulting in an HA-tagged version called TRPM4-HA. This TRPM4-HA was developed to investigate the purification, localization, and function of TRPM4 in different physiological and pathological conditions. TRPM4-HA was successfully expressed in the intact cell membrane and exhibited similar electrophysiological properties, such as the current-voltage relationship, rapid desensitization, and current size, compared to the wild-type TRPM4. The presence of the TRPM4 inhibitor 9-phenanthrol did not affect these properties. Furthermore, a wound-healing assay showed that TRPM4-HA induced cell proliferation and migration, similar to the native TRPM4. Co-expression of protein tyrosine phosphatase, non-receptor type 6 (PTPN6 or SHP1) with TRPM4-HA led to the translocation of TRPM4-HA to the cytosol. To investigate the interaction between PTPN6 and tyrosine residues of TRPM4 in enhancing channel activity, we generated four mutants in which tyrosine (Y) residues were substituted with phenylalanine (F) at the N-terminus of TRPM4. The YF mutants displayed properties and functions similar to TRPM4-HA, except for the Y256F mutant, which showed resistance to 9-phenanthrol, suggesting that Y256 may be involved in the binding site for 9-phenanthrol. Overall, the creation of HA-tagged TRPM4 provides researchers with a valuable tool to study the role of TRPM4 in different conditions and its potential interactions with other proteins, such as PTPN6.

• International Journal of Oral Biology
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• v.33 no.1
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• pp.33-43
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• 2008

In the process of bone remodeling, mineral phase of bone is dissolved by osteoclasts, resulting in elevation of calcium concentration in micro-environment. This study was performed to explore the effect of high extracellular calcium ($Ca{^{2+}}_e$) on mineralized nodule formation and on the expression of progressive ankylosis (Ank), plasma cell membrane glycoprotein-1 (PC-1) and osteopontin by primary cultured mouse calvarial cells. Osteoblastic differentiation and mineralized nodule formation was induced by culture of mouse calvarial cells in osteoblast differentiation medium containing ascorbic acid and ${\beta}$-glycerophosphate. Although Ank, PC-1 and osteopontin are well known inhibitors of mineralization, expression of these genes were induced at the later stage of osteoblast differentiation during when expression of osteocalcin, a late marker gene of osteoblast differentiation, was induced and mineralization was actively progressing. High $Ca{^{2+}}_e$(10 mM) treatment highly enhanced mRNA expression of Ank, PC-1 and osteopontin in the late stage of osteoblast differentiation but not in the early stage. Inhibition of p44/42 MAPK activation but not that of protein kinase C suppressed high $Ca{^{2+}}_{e^-}$induced expression of Ank, PC-1 and osteopontin. When high $Ca{^{2+}}_e$(5 mM or 10 mM) was present in culture medium during when mineral deposition was actively progressing, matrix calcifiation was significantly increased by high $Ca{^{2+}}_e$. This stimulatory effect was abolished by pyrophosphate (5 mM) or levamisole (0.1-0.5 mM), an alkaline phosphatase inhibitor. In addition, probenecid (2mM), an inhibitor of Ank, suppressed matrix calcification in both control and high $Ca{^{2+}}_{e^-}$treated group, suggesting the possible role of Ank in matrix calcification by osteoblasts. Taken together, these results showed that high $Ca{^{2+}}_e$ stimulates expression of Ank, PC-1 and osteopontin as well as matrix calcification in late differentiation stage of osteoblasts and that p44/42 MAPK activation is involved in high $Ca{^{2+}}_{e^-}$induced expression of Ank, PC-1 and osteopontin.

• The Korea Journal of Herbology
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• v.22 no.3
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• pp.27-37
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• 2007

Objectives: Hepatocellular carcinoma is the most common primary malignant tumor of the liver worldwide. In-Jin-Ho-Tang(IJHT) has been used as a traditional Chinese herbal medicine since ancient time. and today it is widely applied as a medication for jaundice which is associated with inflammation in liver. In this study, I investigated whether methanol extract of IJHT induced HepG2 cancer cell death. Methods: Cytotoxic activity of IJHT on HepG2 cells was using XTT assay. Apoptosis induction by Ros A in HCT116 cells was verified by the induction of cleavage of poly ADP-ribose polymerase (PARP). and activation of caspase-3, -8 and -9. The release of cytochrome c from mitochondria to cytosol. the level of Bcl-2 and Bax and the expression of p53 and p21 were examined by western blotting analysis. Furthermore, MAPKs activation was analyzed by western blotting analysis. Results: IJHT induced apoptosis in HepG2 cells. And treatment of IJHT resulted in the release of cytochrome c into cytosol, decreased anti-apoptotic Bcl-2, and increased pri-apoptotic Bax expression. IJHT markedly inactivated extracellular signal-regulated kinase (ERK1/2), and activated p38 mitogen-activated protein (MAP) kinase. Sodium orthovanadate (SOV), a phosphatase inhibitor, to reverse IJHT-induced ERK1/2 inactivation and SB203580, a specific p38 MAP Kinase inhibitor efficiently blocked apoptosis of HepG2. Thus, IJHT induces apoptosis in HepG2 cells via MAP kinase modulation. Conclusion: These results indicated that IJHT has some potential for use as an anti-cancer agent.

• Journal of Life Science
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• v.18 no.9
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• pp.1219-1224
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• 2008

The embryonic zebrafish (Danio rerio) is rapidly becoming an important model organism for studies of early events in vertebrate development. Neural crest-derived pigment cell precursors of the embryonic zebrafish give rise to melanophores, xanthophores, and/or iridophores. Cell-signaling mechanisms related to the development of pigmentation and pigment pattern formation remain obscure. In this study, zebrafish embryos were treated with various signaling-related molecules - LiCl (an inositol-phosphatase inhibitor), forskolin (a protein kinase-A activator), a combination of LiCl/forskolin, and LiCl/heparin (an IP3 inhibitor) in order to identify the mechanisms involved in pigmentation. LiCl treatment resulted in ultrastructural and morphological alterations of melanophores. To identify the possible proteins responsible for this ultrastructural and morphological change, phosphorylation patterns in vitro and in vivo were analyzed. LiCl and LiCl/forskolin treatment elicited dramatic increases in the phosphorylation of a 55-kDa protein which was inhibited by heparin treatment. LiCl treatment also induced phosphorylation of a 55-kDa protein in melanophores purified from adult zebrafish. Collectively these results suggest that a LiCl-induced 55-kDa phosphoprotein plays a role in melanophore morphology and ultrastructure and ultimately effects gross pigmentation.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.224-234
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• 2006

We employed human SK-MEL-28 cells as a model system to identify cellular proteins that accompany N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate (MMTC)-induced apoptosis based on a proteomic approach. Cell viability tests revealed that SK-MEL-28 skin cancer cells underwent more cell death than normal HaCaT cells in a dose-dependent manner after treatment with MMTC. Two-dimensional electrophoresis in conjunction with matrixassisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis or computer matching with a protein database further revealed that the MMTC-induced apoptosis is accompanied by increased levels of caspase-1, checkpoint suppressor-1, caspase-4, NF-kB inhibitor, AP-2, c-Jun-N-terminal kinase, melanoma inhibitor, granzyme K, G1/S specific cyclin D3, cystein rich protein, Ras-related protein Rab-37 or Ras-related protein Rab-13, and reduced levels of EMS (oncogene), ATP synthase, tyrosine-phosphatase, Cdc25c, 14-3-3 protein or specific structure of nuclear receptor. The migration suppressing effect of MMTC on SK-MEL-28 cell was tested. MMTC suppressed the metastasis of SK-MEL-8 cells. It was also identified that MMTC had little angiogenic effect because it did not suppress the proliferation of HUVEC cell line. These results suggest that MMTC is a novel chemotherapeutic and metastatic agents against the SK-MEL-28 human melanoma cell line.

• IMMUNE NETWORK
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• v.6 no.1
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• pp.33-42
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• 2006

Background: Calcineurin plays a crucial role in T cell activation, cell growth, apoptosis, and angiogenesis, and its over-expression has been implicated in the pathogenesis of cardiomyopathy and stroke. However, the expression and function of calcineurin in the pathologic lesion of chronic inflammatory diseases, like rheumatoid synovium, remain to be defined. This study was aimed to determine the role of calcineurin in inflammatory arthritis and investigate the expression and function of calcineurin in the rheumatoid synovium and synoviocytes, the actual site of chronic inflammation. Methods: Immuno-histochemical staining using specific antibody to calcineurin was perfomed in the synovium of rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLS) from RA and osteoarthritis (OA) patients were isolated from RA and OA patients, and cultured with IL-1${\beta}$ and TNF-${\alpha}$ in the presence or absence of cyclosporin A, a calcineurin inhibitor. The calcineurin expression was assessed by phosphatase assay and Western blotting analysis. IL-6, -10, -17, matrix metalloproteinase (MMP)-1, -2, -3, and -9 released into the culture supernatants were measured by ELISA. After transfection with GFP-Cabin 1 gene into synoviocytes, the levels of IL-6 and MMPs were measured by ELISA. Results: Calcineurin was highly expressed in the lining layer of synovium and cultured synoviocytes of RA patients. The elevated calcineurin activity in the rheumatoid synoviocytes was triggered by proin flammatory cytokines such as IL-1${\beta}$ and TNF-${\alpha}$. In contrast, IL-10, an anti-inflammatory cytokine, failed to increase the calcineurin activity. The targeted inhibition of calcineurin by the over-expression of Cabin 1, a natural calcineurin antagonist, inhibited the production of IL-6 and MMP-2 by rheumatoid synoviocytes in a similar manner to the calcineurin inhibitor, cyclosporin A. Conclusion: These data suggest that abnormal activation of calcineurin in the synoviocytes may contribute to the pathogenesis of chronic arthritis, and thus provide a potential target for controlling inflammatory arthritis.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.2
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• pp.111-118
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• 2015

Osteoprotegerin (OPG), receptor activator of NF-${\kappa}B$ ligand (RANKL)/receptor activator of NF-${\kappa}B$ (RANK) axis, and TNF-related apoptosis-inducing ligand (TRAIL) participate in vascular calcification process including atherosclerosis, but their contributions under high glucose (HG) and phosphate (HP) condition for a long-term period (more than 2 weeks) have not been fully determined. In this study, we evaluated the effects of HG and HP levels over 2 or 4 weeks on the progression of vascular calcification in rat vascular smooth muscle cells (VSMCs). Calcium deposition in VSMCs was increased in medium containing HG (30 mmol/L D-glucose) with ${\beta}$-glycerophosphate (${\beta}$-GP, 12 mmol/L) after 2 weeks and increased further after 4 weeks. OPG mRNA and protein expressions were unchanged in HG group with or without ${\beta}$-GP after 2 weeks. However, after 4 weeks, OPG mRNA and protein expressions were significantly lower in HG group with ${\beta}$-GP. No significant expression changes were observed in RANKL, RANK, or TRAIL during the experiment. After 4 weeks of treatment in HG group containing ${\beta}$-GP and rhBMP-7, an inhibitor of vascular calcification, OPG expressions were maintained. Furthermore, mRNA expression of alkaline phosphatase (ALP), a marker of vascular mineralization, was lower in the presence of rhBMP-7. These results suggest that low OPG levels after long term HG and phosphate stimulation might reduce the binding of OPG to RANKL and TRAIL, and these changes could increase osteo-inductive VSMC differentiation, especially vascular mineralization reflected by increased ALP activity during vascular calcification.

• Parasites, Hosts and Diseases
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• v.58 no.3
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• pp.249-255
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• 2020

Toxoplasma gondii, a ubiquitous, intracellular parasite of the phylum Apicomplexa, infects an estimated one-third of the human population as well as a broad range of warm-blooded animals. We have observed that some tyrosine kinase inhibitors suppressed the growth of T. gondii within host ARPE-10 cells. Among them, afatinib, human epithermal growth factor receptor 2 and 4 (HER2/4) inhibitor, may be used as a therapeutic agent for inhibiting parasite growth with minimal adverse effects on host. In this report, we conducted a proteomic analysis to observe changes in host proteins that were altered via infection with T. gondii and the treatment of HER2/4 inhibitors. Secreting proteins were subjected to a procedure of micor basic reverse phase liquid chromatography, nano-liquid chromatography-mass spectrometry, and ingenuity pathway analysis serially. As a result, the expression level of heterogeneous nuclear ribonucleoprotein K, semaphorin 7A, a GPI membrane anchor, serine/threonine-protein phosphatase 2A, and calpain small subunit 1 proteins were significantly changed, and which were confirmed further by western blot analysis. Changes in various proteins, including these 4 proteins, can be used as a basis for explaining the effects of T. gondii infections and HER2/4 inhibitors.