• Biodesign
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• v.5 no.3
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• pp.122-125
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• 2017

Receptor for advanced glycation end products (RAGE) is one of the single transmembrane domain containing receptors and causes various inflammatory diseases including diabetes and atherosclerosis. RAGE extracellular domain has three consecutive IgG-like domains (V-C₁-C₂ domain) which interact with various soluble ligands including heparan sulfate or HMGB1. Studies have shown that each ligand induces different oligomeric forms of RAGE which results in a ligand-specific signal transduction. The structure of mouse RAGE bound to heparan sulfate has been previously determined but the electron density map of heparan sulfate was too ambiguous that the exact position of heparin sulfate could not be defined. Furthermore, the complex structure of human RAGE and heparin sulfate still remains elusive. Therefore, to determine the structure, human RAGE was overexpressed using bacterial expression system and crystallized using the sitting drop method in the condition of 0.1 M sodium acetate trihydrate pH 4.6, 8 % (w/v) polyethylene glycol 4,000 at 290 K. The crystal diffracted to 3.6 Å resolution and the space group is C121 with unit cell parameters a= 206.04 Å, b= 68.64 Å, c= 98.73 Å, α= 90.00°, β= 90.62°, γ= 90.00°.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.3
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• pp.169-174
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• 2019

The purpose of this study was to evaluate the inhibitory effects of Juglans regia complex extract(JCE) consisted of Juglans regia, Eucommia ulmoides, Eleutherococcus senticosus and Zingiber officinale on osteoclast differentiation. Cell toxicity test by using CCK-8, TRAP activity and TRAP positive multi-nucleated cell counting were performed to evaluate inhibitory effect on differentiation of osteoclast from bone marrow derived macrophages(BMMs) induced by receptor activator of nuclear $factor-{\kappa}B$ ligand(RANKL). As a result, JCE inhibited RANKL-induced osteoclast differentiation in BMMs dose-dependently without cytotoxicity. These results suggest that JCE may have a potential role for treating bone lytic diseases such as osteoporosis.

• BMB Reports
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• v.54 no.1
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• pp.2-11
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• 2021

Antibody-based therapeutics targeting the inhibitory receptors PD-1, PD-L1, or CTLA-4 have shown remarkable clinical progress on several cancers. However, most patients do not benefit from these therapies. Thus, many efforts are being made to identify new immune checkpoint receptor-ligand pathways that are alternative targets for cancer immunotherapies. Nectin and nectin-like molecules are widely expressed on several types of tumor cells and play regulatory roles in T- and NK-cell functions. TIGIT, CD226, CD96 and CD112R on lymphoid cells are a group of immunoglobulin superfamily receptors that interact with Nectin and nectin-like molecules with different affinities. These receptors transmit activating or inhibitory signals upon binding their cognate ligands to the immune cells. The integrated signals formed by their complex interactions contribute to regulating immune-cell functions. Several clinical trials are currently evaluating the efficacy of anti-TIGIT and anti-CD112R blockades for treating patients with solid tumors. However, many questions still need to be answered in order to fully understand the dynamics and functions of these receptor networks. This review addresses the rationale behind targeting TIGIT, CD226, CD96, and CD112R to regulate T- and NK-cell functions and discusses their potential application in cancer immunotherapy.

• Development and Reproduction
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• v.10 no.2
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• pp.85-92
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• 2006

Progesterone(P4) is an important intermediate in the synthesis of androgens and estrogens. Furthermore, P4 itself plays a crucial role in ovulation, atresia and luteinization, and is essential for the continuation of early pregnancy in all mammalian species. In spite of the hormone's physiological importance, the exact action mechanism(s) of P4 in mammalian ovary has not been fully understood yet. In this context, a decades-long controversy regarding the identity of receptors that mediate non-genomic, transcription-independent cellular responses to P4 is presently attracting huge scientific interests. P4 may exert its action in mammalian ovary by several ways: 1) the well-documented genomic pathway, involving hormone binding to so-called classic cytosolic receptor(PGR) and subsequent modulation of gene expression by the ligand-receptor complex as transcription factor. 2) pathways are operating that do not act on the genome, therefore refered to as non-genomic actions. The prominent characteristics of the non-genomic P4 actions are: (i) rapid, (ii) insensitive to transcription inhibitors, (iii) transduced by membrane associated molecules. In particular, the non-genomic P4 actions could be mediated by: (a) classic genomic P4 receptor(PGR) that localizes at or near the plasma membrane, (b) a family of membrane progestin receptors(MPR $\alpha$, MPR $\beta$ and MPR $\gamma$), (c) progesterone receptor membrane component I(PGRMC1), and (d) a membrane complex composed of serpine I mRNA binding protein(SERBP1). The present review summarized these rapid signaling pathways of P4 in the mammalian ovary.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1209-1213
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• 2005

Nuclear membrane is one of the main barriers in intracellular delivery of genetic materials. The previous report showed that glucocorticoid receptor dilated the nuclear pore to 60 nm in the presence of a ligand. It was also suggested that the transport of genetic material to nucleus might be facilitated by glucocorticoid. In this study, the effect of glucocorticoid preincubation in the polymeric gene delivery was investigated. The cells were preincubated with dexamethasone, a potent glucocorticoid, and transfection assays were performed with polyethylenimine (PEI) and polyamidoamine (PAMAM) dendrimer. As a result, the transfection efficiency of PEI or PAMAM to the cells in the presence of dexamethasone was enhanced, compared to the cells without dexamethasone. This effect was not observed in the cells preincubated with cholesterol. The polymer/DNA complex was stable in the presence of dexamethasone. In addition, the cytotoxicities of the polymeric carriers to the cells were observed in the presence of dexamethasone. In conclusion, dexamethasone enhances the transfection efficiency of polymeric carriers and may be useful in the development of polymeric gene carriers.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.49-49
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• 2001

Sphingosine 1-phosphate is a metabolite of complex sphingolipids that acts as both a second messenger and as a high-affinity ligand for cell surface receptor. Since the possible involvement of sphingosine 1-phosphate has not been investigated in adipocyte, we examined the response of intracellular calcium ([Ca$^{2＋}$]$_{i}$) and intracellular cAMP ([cAMP]$_{i}$ and the effect of sphingosine 1-phosphate on adipocyte function using rat primary adipocyte.(omitted)ted)

• Journal of Life Science
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• v.19 no.12
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• pp.1690-1697
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• 2009

CD11c and costimulatory molecules such as CD80 and CD86 express mainly in dendritic cells (DCs). In this study, we investigated the biologic effects of recombinant Fms-like tyrosine kinase-3 (Flt-3) ligand on the expression of DC surface markers, including CD11c in leukemia cell lines, such as KG-1, HL-60, NB4, and THP-1 cells. The expression of the Flt-3 receptor was found in NB4 and HL-60 cells, as well as KG-1 cells, but not in THP-1 cells. When KG-1 cells were cultured in a medium containing Flt-3 ligand or granulocyte macrophage-colony stimulating factor (GM-CSF) plus tumor necrosis factor (TNF)-$\alpha$, cell proliferation was inhibited and the expression levels of CD11c, major histocompatibility complex (MHC)-I, and MHC-II were increased in the cells. Flt-3 ligand also increased the expression level of CD11c on HL-60 and NB4 cells, but not on THP-1 cells. In comparison with CD11c expression, the expression level of CD11b on KG-1 cells, but not on NB4 and HL-60 cells, was slightly increased by Flt-3 ligand. Flt-3 ligand induced phosphorylation of extracellular signal-regulated kinase-1/2 (ERK-1/2) and p38-mitogen-activated protein kinase (p38-MAPK) in KG-1 cells, and the up-regulation of CD11c expression by Flt-3 ligand in the cells was abrogated by PD98059, an inhibitor of MEK. The results suggest that Flt-3 ligand up-regulates DC surface markers on $CD34^+$ myelomonocytic KG-1 cells, as well as promyelocytic leukemia cells, and that the differentiation of the leukemia cells into DC-like cells by Flt-3 ligand is mediated by ERK-1/2 activity.

• Molecules and Cells
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• v.39 no.4
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• pp.316-321
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• 2016

The receptor activator of nuclear factor ${\kappa}B$ (RANK) and its ligand RANKL are key regulators of osteoclastogenesis and well-recognized targets in developing treatments for bone disorders associated with excessive bone resorption, such as osteoporosis. Our previous work on the structure of the RANK-RANKL complex revealed that Loop3 of RANK, specifically the non-canonical disulfide bond at the tip, performs a crucial role in specific recognition of RANKL. It also demonstrated that peptide mimics of Loop3 were capable of interfering with the function of RANKL in osteoclastogenesis. Here, we reported the structure-based design of a smaller peptide with enhanced inhibitory efficiency. The kinetic analysis and osteoclast differentiation assay showed that in addition to the sharp turn induced by the disulfide bond, two consecutive arginine residues were also important for binding to RANKL and inhibiting osteoclastogenesis. Docking and molecular dynamics simulations proposed the binding mode of the peptide to the RANKL trimer, showing that the arginine residues provide electrostatic interactions with RANKL and contribute to stabilizing the complex. These findings provided useful information for the rational design of therapeutics for bone diseases associated with RANK/RANKL function.

• Toxicological Research
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• v.31 no.1
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• pp.11-16
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• 2015

Our body's immune system has defense mechanisms against pathogens such as viruses and bacteria. Immune responses are primarily initiated by the activation of toll-like receptors (TLRs). In particular, TLR4 is well-characterized and is known to be activated by gram-negative bacteria and tissue damage signals. TLR4 requires myeloid differentiation factor 2 (MD2) as a co-receptor to recognize its ligand, lipopolysaccharides (LPS), which is an extracellular membrane component of gram-negative bacteria. Gambogic acid is a xanthonoid isolated from brownish or orange resin extracted from Garcinia hanburyi. Its primary effect is tumor suppression. Since inflammatory responses are related to the development of cancer, we hypothesized that gambogic acid may regulate TLR4 activation. Our results demonstrated that gambogic acid decreased the expression of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, IL-12, and $IL-1{\beta}$) in both mRNA and protein levels in bone marrow-derived primary macrophages after stimulation with LPS. Gambogic acid did not inhibit the activation of Interferon regulatory factor 3 (IRF3) induced by TBK1 overexpression in a luciferase reporter gene assay using IFN-${\beta}$-PRD III-I-luc. An in vitro kinase assay using recombinant TBK1 revealed that gambogic acid did not directly inhibit TBK1 kinase activity, and instead suppressed the binding of LPS to MD2, as determined by an in vitro binding assay and confocal microscopy analysis. Together, our results demonstrate that gambogic acid disrupts LPS interaction with the TLR4/MD2 complex, the novel mechanism by which it suppresses TLR4 activation.

• Genomics & Informatics
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• v.21 no.2
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• pp.17.1-17.12
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• 2023

Coronavirus has left severe health impacts on the human population, globally. Still a significant number of cases are reported daily as no specific medications are available for its effective treatment. The presence of the CD147 receptor (human basigin) on the host cell facilitates the severe acute respiratory disease coronavirus 2 (SARS-CoV-2) infection. Therefore, the drugs that efficiently alter the formation of CD147 and spike protein complex could be the right drug candidate to inhibit the replication of SARS-CoV-2. Hence, an e-Pharmacophore model was developed based on the receptor-ligand cavity of CD147 protein which was further mapped against pre-existing drugs of coronavirus disease treatment. A total of seven drugs were found to be suited as pharmacophores out of 11 drugs screened which was further docked with CD147 protein using CDOCKER of Biovia discovery studio. The active site sphere of the prepared protein was 101.44, 87.84, and 97.17 along with the radius being 15.33 and the root-mean-square deviation value obtained was 0.73 Å. The protein minimization energy was calculated to be -30,328.81547 kcal/mol. The docking results showed ritonavir as the best fit as it demonstrated a higher CDOCKER energy (-57.30) with correspond to CDOCKER interaction energy (-53.38). However, authors further suggest in vitro studies to understand the potential activity of the ritonavir.